JP4114618B2 - Antenna and manufacturing method thereof - Google Patents

Description

  The present invention relates to an antenna suitable for an ultra-wide band transmission system and the like and a manufacturing method thereof.

In recent years, a communication technique called an ultra wide band (UWB) transmission method has attracted attention.
The UWB transmission system transmits information by transmitting an impulse signal having a very short pulse width (for example, 1 nsec or less) at a predetermined repetition period. Accordingly, the occupied frequency bandwidth is very wide compared to the bandwidth normally used in mobile phones and wireless LAN communications, and the value obtained by dividing the occupied bandwidth by the center frequency (for example, 1 to 10 GHz) is approximately 1 for example. It becomes.
Since the UWB transmission system has the feature of ultra-wide bandwidth of the order of GHz as described above, it is promising as a transmission system capable of realizing ultra-high-speed wireless transmission of the order of 100 Mbps in a wireless personal area network (wireless PAN).

In the wireless PAN, wireless communication is performed by mounting a short-range wireless communication device on a wireless communication terminal such as a portable information terminal device or a notebook computer.
As such a short-range wireless communication device, a broadband antenna characterized by forming a plurality of element antennas having different center frequencies on a printed circuit board has been proposed (see Patent Document 1). The element antenna looks like a narrow band dipole pattern antenna.
On the other hand, a PC card type wireless LAN card that can be attached to and detached from a card slot of a notebook computer has been proposed as such a short-range wireless communication device in wireless LAN, although it is not a wireless PAN (see Patent Document 2). The size of the wireless LAN card is approximately 85 mm in the length in the card slot (hereinafter simply referred to as length), and the width in the card slot (hereinafter sometimes simply referred to as width). It is described as about 57 mm.

Japanese Patent Laying-Open No. 2003-101342 (FIG. 1) Japanese Patent Laying-Open No. 2003-273632 (FIG. 13)

  Since the wideband antenna described in Patent Document 1 seems to use a dipole pattern antenna, its length should be λ / 2 where λ is a communication wavelength, and at a typical center frequency of 3 GHz The length is 50 mm. Therefore, the length of the broadband antenna that must be formed by arranging at least two such dipole pattern antennas is typically 100 mm or more, and the size is not necessarily small.

The wireless LAN card described in Patent Document 2 can be regarded as an antenna mounted on a PC card (length: 85.6 mm, width: 54 mm). The specific bandwidth described later is estimated to be about 1 to 2%, so that it is difficult to use in the UWB transmission system.
An object of the present invention is to provide an antenna that can solve the above problems and a method for manufacturing the antenna.

  In the present invention, an axially symmetric planar radiating conductor whose both surfaces are covered with a dielectric is on one surface of an insulating substrate, and a ground conductor is on the inside of the substrate or on the other surface where the radiating conductor is not formed. Provided is an antenna (hereinafter referred to as antenna A of the present invention) having a dielectric constant or effective dielectric constant at 1 MHz of a dielectric formed and covering both surfaces of the radiation conductor of 8 to 18.

  An axially symmetric planar radiating conductor whose both surfaces are covered with a dielectric is formed on one surface of the insulating substrate, and a ground conductor is formed on the inside of the substrate or on the other surface where the radiating conductor is not formed. Provided is an antenna (hereinafter referred to as the antenna B of the present invention) in which the length of the ground conductor in the symmetry axis direction of the ground conductor is 35 mm or less and the relative bandwidth at 1 to 30 GHz is 10% or more.

  Further, at least one of the dielectrics covering both surfaces of the axially symmetric planar radiating conductor is composed of two or more dielectric layers having a relative dielectric constant of 5 to 40 at 1 MHz and different relative dielectric constants. And providing the antenna having a relative dielectric constant of a dielectric layer closer to the radiating conductor of adjacent dielectric layers larger than a dielectric constant of a dielectric layer further away from the radiating conductor.

  Each of the dielectrics covering both surfaces of the axially symmetric planar radiating conductor is composed of two dielectric layers, and a dielectric layer closer to the radiating conductor has a relative dielectric constant at 1 MHz of 11 to 35, The method for manufacturing an antenna according to claim 1, wherein a dielectric layer further away from the radiation conductor has a relative dielectric constant at 1 MHz of 5 to 15 and is fired to become a dielectric layer having a relative dielectric constant of 11 to 35 A powder-containing high dielectric constant green sheet (hereinafter simply referred to as a high dielectric constant green sheet) and a glass powder-containing low dielectric constant green sheet (hereinafter simply referred to as a low dielectric constant green sheet) to be fired to become a dielectric layer having a relative dielectric constant of 5 to 15. The required number of dielectric constant green sheets) is prepared and fired to form a conductor paste pattern to be an axially symmetric planar radiation conductor on one surface of each of the green sheets. Then, these green sheets are laminated and fired to produce a dielectric-covered axisymmetric planar radiating conductor, and the dielectric-covered axisymmetric planar radiating conductor has a ground conductor formed inside or on one side. Provided is a method for manufacturing an antenna, which is fixed to a surface of an insulating substrate where a ground conductor is not formed.

  According to the present invention, a small-sized and wide-band antenna can be obtained. For example, in one aspect, a wide-band antenna that can be used in the UWB transmission system is a compact flash card (length) smaller than that of a PC card. : 42.8 mm, width: 36.4 mm, hereinafter referred to as a CF card).

The antenna of the present invention is suitable for an antenna in a frequency range of 1 to 100 GHz, typically 1 to 30 GHz used for communication, ranging or broadcasting.
The specific bandwidth (Δf) at 1 to 30 GHz of the antenna B of the present invention is 10% or more. If it is less than 10%, it becomes difficult to use the UWB transmission system. Preferably it is 35% or more, more preferably 80% or more, particularly preferably 90% or more, and most preferably 100% or more.
Δf of the antenna A of the present invention is preferably 10% or more, more preferably 35% or more, still more preferably 80% or more, particularly preferably 90% or more, and most preferably 100% or more.

Δf (unit:%) is obtained from the frequency characteristics of VSWR (Voltage Standing Wave Ratio) at 1 to 30 GHz. That is, Δf is expressed by the following equation, where f _H and f _L are the maximum and minimum frequencies at which VSWR is 2 or less in the frequency range of 1 to 30 GHz.
Δf = 2 × [(f _H −f _L ) / (f _H + f _L )] × 100.

  VSWR is an index indicating whether or not the impedance matching between the radiation conductor and the transmission line connected to the radiation conductor is satisfactorily performed, and is a ratio between the maximum value and the minimum value of the voltage signal that appears as a standing wave. is there. When impedance matching is completely performed, VSWR is 1. However, when impedance matching is incomplete, a part of the transmission signal traveling wave is reflected and receded due to discontinuity at the connection portion between the transmission line and the radiation conductor. A standing wave is generated by the coexistence of both waves. As VSWR increases beyond 1, the return loss in the antenna increases and the antenna characteristics deteriorate.

The antennas A and B of the present invention (sometimes collectively referred to as the antenna of the present invention) will be described below with reference to FIGS. 1 and 2, but the present invention is not limited thereto.
FIG. 2 is a plan view of the antenna 1 of the present invention, and FIG. 1 is a cross-sectional view of the antenna 1 shown in FIG.

The antenna element 10 and the signal line 19 are formed on one surface (upper surface) of the insulating substrate 17, and the ground conductor 18 is formed on the other surface (bottom surface). The ground conductor 18 is formed on the bottom surface of the insulating substrate 17. The portion where no is formed is the exposed portion 24.
The insulating substrate 17 is a substrate made of a material that can be used as a circuit substrate, and is usually a resin substrate having a relative dielectric constant of 3 to 6 at 1 MHz, 1 GHz, or 1 MHz to 10 GHz, such as a substrate such as FR4 or BT resin. The typical dimensions are 0.1 to 2.0 mm in thickness, 20 to 40 mm in width, and 20 to 50 mm in length.

The ground conductor 18 is formed on the bottom surface of the insulating substrate 17.
The length L (described later) L of the ground conductor 18 in the radial conductor axis direction is 35 mm or less in the antenna B of the present invention. Since it is difficult to make the size of the antenna element 10 less than 8 mm, it is difficult to mount the antenna A of the present invention on a CF card (length: 42.8 mm) if L is more than 35 mm. L is preferably 30 mm or less.
L of the antenna A of the present invention is preferably 35 mm or less, more preferably 30 mm or less.

The length of the ground conductor 18 in the direction orthogonal to the radial conductor axial direction, that is, the width of the ground conductor 18 is preferably 36 mm or less. If it exceeds 36 mm, for example, the antenna of the present invention cannot be mounted on a CF card (width: 36.4 mm).
Although the ground conductor 18 is formed on the bottom surface of the insulating substrate 17 in FIGS. 1 and 2, it may be formed inside the insulating substrate 17 so as to be parallel to the surface of the substrate. Even in this case, the length of the ground conductor 18 in the radial conductor axial direction is determined in the same manner as L.

  The signal line 19 is a signal line of a microstrip line transmission line, and its typical width is 0.1 to 5.0 mm. The signal line 19 is not limited to the one formed on a surface different from the surface on which the ground conductor 18 is formed in this way. For example, the signal line may be formed on the same surface as the ground conductor to form a coplanar line.

The antenna element 10 is usually provided on a portion of the upper surface of the insulating substrate 17 facing the exposed portion 24, that is, the antenna element 10 and the ground conductor 18 are not overlapped. Even when the antenna element 10 and the ground conductor 18 are overlapped, the overlapping length is, for example, 5 mm or less.
The length of the antenna element 10 in the radial conductor axial direction is preferably 20 mm or less. If it exceeds 20 mm, the antenna of the present invention may not be mounted on the CF card. More preferably, it is 15 mm or less.
The length of the antenna element 10 in the direction orthogonal to the radial conductor axis direction, that is, the width of the antenna element 10 is typically 15 mm or less.

  The antenna element 10 is an element that essentially includes an axially symmetric planar radiating conductor (hereinafter simply referred to as a radiating conductor) 11 and dielectrics 12 and 13 that respectively cover the lower surface and the upper surface thereof.

Although the planar pattern of the radiation conductor 11 has at least one symmetry axis, it is preferable that the symmetry axis is one.
The axis of symmetry of the radiation conductor 11 is normally orthogonal to the boundary line between the ground conductor 18 and the exposed portion 24. Hereinafter, the direction of the symmetry axis is referred to as a radiation conductor axial direction.

The plane pattern of the radiation conductor 11 is such that a circle and a semi-ellipse (the original ellipse divided into two at right angles to the major axis direction or the minor axis direction) are overlapped so that the line connecting their centers becomes the axis of symmetry. is there. The center of the semi-ellipse is the center of the original ellipse.
In such a plane pattern, typically, the diameter of the circle is 4 to 9.5 mm, the major axis radius of the original ellipse is 1 to 7 mm, the minor axis radius is 0.2 to 3 mm, and the major axis radius / minor axis. The radius is 0.3 to 35, and the ratio of the circle diameter to the length of the planar pattern in the radial conductor axis direction is 0.5 to 0.9.
The planar pattern of the radiating conductor 11 is not limited to this, and examples include an ellipse in place of the circle and / or a trapezoid or rectangle in place of the semi-ellipse, a simple ellipse, and a simple circle. Is done.

The dielectric 12 is composed of two dielectric layers 12a and 12b, and the dielectric 13 is composed of two dielectric layers 13a and 13b. The effective permittivity (ε _eff ) of the dielectrics 12 and 13 at 1 MHz is the present invention. It is 8-18 in the antenna A. For example, ε _eff of the dielectric ₁₂ is (ε _12a × t _12a + ε _12b × t _12b ) / (t, where ε _12a and ε _12b and the thicknesses t _12a and t _12b are ε of the dielectric layers 12a and 12b _12a + t _12b ), and when the dielectric 12 is a single dielectric layer unlike FIG. 1, ε _eff is equal to the relative dielectric constant (ε) of the dielectric layer at 1 MHz.
When ε _{eff of the} dielectrics 12 and 13 is less than 8, Δf becomes small. Preferably it is 10 or more. Even if it exceeds 18, Δf becomes small. Preferably it is 17 or less.
In the antenna B of the present invention, ε _{eff of the} dielectrics 12 and 13 is preferably 8-18. More preferably, it is 10 or more and 17 or less.

When it is desired to increase Δf or the like, at least one of the dielectrics 12 and 13 is composed of two or more dielectric layers having ε of 5 to 40 and ε different from each other. It is preferable that ε of the dielectric layer closer to the radiating conductor 11 is larger than ε of the dielectric layer further away from the radiating conductor. In the case of FIG. 1, ε _12a and ε _12b are 5 to 40 and ε _12a > ε _12b and / or ε _13a and ε _13b are 5 to 40 and ε _13a > ε _13b . . Here, ε _13a and ε _13b are ε of the dielectric layers 13a and 13b.

Each of the dielectrics 12 and 13 is composed of two or more dielectric layers having ε of 5 to 40 and different from each other, and ε of the dielectric layer closer to the radiating conductor 11 of the adjacent dielectric layers. Is larger than ε of the dielectric layer farther away from the radiating conductor, the number of dielectric layers having different ε in the dielectrics 12 and 13 is typically equal, and is in contact with the radiating conductor 11. By counting the first layer, the second layer,... From the layer, the ε and the thickness of each of the nth dielectric layers of the dielectrics 12 and 13 are equal. In the case of FIG. 1, the thicknesses of the dielectric layers 13a and 13b are typically _t13a and _t13b , and typically _ε12a = _ε13a , _ε12b = _ε13b , _t12a = _t13a , and _t12b = _t13b. It is.

As shown in FIG. 1, when the dielectric 12 and the dielectric 13 are each composed of two dielectric layers 12a and 12b and dielectric layers 13a and 13b, ε of the dielectric layers 12a and 13a closer to the radiating conductor 11, that is, ε _12a, epsilon _13a is 11 to 35 both, the dielectric layer 12b which is more remote from the radiation conductor 11, 13b of epsilon that epsilon _12b, that epsilon _13b is 5-15 either to increase the Δf Therefore, it is preferable (hereinafter, this preferable mode is referred to as the present antenna). In FIG. 1, the dielectric layers 12a and 13a are made of different substances (dielectrics), and their interfaces are clearly shown.
At least one of ε _12a and ε _13a is 15 to 30, and ε _13b is more preferably 6 to 10.

From the three layers in which the dielectric 12 is laminated in the order of the dielectric layers 12a, 12b, and 12c from the side close to the radiation conductor 11, the dielectric 13 is in the order of the dielectric layers 13a, 13b, and 13c from the side near the radiation conductor 11. Ε _12a and ε _13a are 16 to 40, ε _12b and ε _13b are 10 to 16, and ε _12a and ε _13a are expressed as subscripts attached to each layer name. preferably _12c and epsilon _13c are 5-10, typically this _{case, ε 12a = ε 13a, ε} 12b = ε 13b, are epsilon _12c = epsilon _13c.

The radiation conductor 11 is connected to the signal line 19 through the feeder line 14 and the via 20. The method of connecting the radiation conductor 11 and the signal line 19 is not limited to this, and for example, a signal line pattern may be formed on the end faces of the dielectrics 12 and 13 to replace the via 20.
Further, in order to perform impedance matching of the radiating conductor 11, ground patterns 15 and 15 are formed on the left and right sides of the feeder line 14 on the surface to be in contact with the insulating substrate 17 of the antenna element 10 so that the potential is zero. The ground patterns 15 and 15 are both connected to the ground conductor 18 via a bonding pad (not shown) and a via in the insulating substrate 17.

Next, the manufacturing method of the antenna, that is, the manufacturing method of the antenna of the present invention will be described.
The green sheet in the present invention comprises an inorganic component and an organic component. In addition to glass powder, which is an essential component, the inorganic component is exemplified by ceramic powder as an optional component, and as the organic component, plasticizer is exemplified in addition to the organic binder, which is an essential component.

  One or a plurality of low dielectric constant green sheets containing the first glass powder, one or more high dielectric constant green sheets containing the first glass powder, and a second high dielectric constant green sheet thereon One or a plurality of sheets, and one or a plurality of second low dielectric constant green sheets are laminated thereon, and the unfired dielectric layers 12β to be baked to become the dielectric layers 12b, 12a, 13a, 13b, A green sheet layer made of 12α, 13α, and 13β is prepared.

The layer made of the second high dielectric constant green sheet (unfired dielectric layer 13α) faces the first high dielectric constant green sheet layer (unfired dielectric layer 12α) and is fired and radiated. A conductor paste pattern to be the conductor 11 and the feeder 14 is usually formed by screen printing using silver paste.
Also, a hole is made in the lower green sheet layer made of the unfired dielectric layers 12α and 13α, and a conductor paste filling hole to be the via 20 is usually formed by filling a silver paste there.
Also, a conductor paste pattern to be the ground pattern 15 is formed on the surface of the first low dielectric constant green sheet that is the lower surface of the lower green sheet.
In addition, processing for forming an auxiliary pattern, a conductor paste pattern to be a bonding via, a conductor paste filling hole, and the like is performed.

The green sheet layer composed of the unfired dielectric layers 12β, 12α, 13α, and 13β is thermocompression-bonded, decomposed and removed from the binder in the green sheet, fired, and cut into desired dimensions as necessary to form the antenna element 10. .
The thermocompression bonding is performed by pressing the green sheet layer typically at 80 ° C. for 5 minutes.
Decomposition and removal of the binder is typically performed by holding the thermocompression-bonded green sheet layer at 550 ° C. for 5 hours.
The calcination is typically performed at a temperature of 950 ° C. or lower. Above 950 ° C., silver melts when silver paste is used as the conductor paste. In this case, the firing temperature is preferably 900 ° C. or lower, typically 800 to 900 ° C., more typically 830 to 870 ° C.

  On the other hand, a double-sided copper-clad resin substrate (for example, R-1766T manufactured by Matsushita Electric Works) is etched to produce the insulating substrate 17 having the ground conductor 18 and the exposed portion 24 on the bottom surface and the signal line 19 on the top surface. . Two bonding pads (not shown) to be in contact with the ground patterns 15, 15 are provided on the upper surface of the insulating substrate 17, and bonding vias (not shown) for electrically connecting the pads and the ground conductor 18. Are formed inside the insulating substrate 17.

  The lead-free cream solder is printed using a metal mask so as to cover the bonding pads, and the antenna element 10 is placed thereon so that the antenna patterns 15 and 15 are placed thereon, and then heated to, for example, 250 ° C. to insulate the insulating substrate 17. The antenna element 10 is fixed to the upper surface of the substrate.

It is preferable that the glass transition point (T _G ) of the glass powder contained in the high dielectric constant green sheet and the low dielectric constant green sheet is 800 ° C. or less. If it exceeds 800 ° C., dense dielectric layers 12 a and 13 a may not be obtained when baked at a temperature of 950 ° C. or lower. Preferably it is 700 degrees C or less, More preferably, it is 650 degrees C or less. _TG is typically 550 ° C. or higher. Normally, the conductive paste pattern to be the radiation conductor 11 is formed using a silver paste as a conductive paste, and is fired simultaneously with a high dielectric constant green sheet and a low dielectric constant green sheet at a temperature of 950 ° C. or lower. If _TG exceeds 800 ° C., such co-firing may be difficult in practice.

The glass powder preferably has a mass average particle diameter (D ₅₀ ) of 1 to 10 μm. If it is less than 1 μm, it is difficult to uniformly disperse the glass powder in the green sheet. More preferably, it is 1.5 micrometers or more, Most preferably, it is 2 micrometers or more. If it exceeds 10 μm, it becomes difficult to obtain a dense fired body (dielectric layer). More preferably, it is 5 micrometers or less, Most preferably, it is 3.5 micrometers or less.

The glass powder contained in the high dielectric constant green sheet and low dielectric constant green sheet is intended to suppress the chemical reaction between the high dielectric constant green sheet and low dielectric constant green sheet glass during firing. In the case where it is desired to make the _TG of the green sheet glass equal to reduce the mismatch in the firing shrinkage behavior of both green sheets and to reduce the deformation and warpage of the dielectric layer, it is preferable to have the same composition.

It is preferable that both the high dielectric constant green sheet and the low dielectric constant green sheet consist essentially of glass powder of 30 to 90% and ceramic powder of 10 to 70% in terms of mass percentage.
The _{D 50} of the ceramic powder is preferably 0.5 to 15 m. If it exceeds 15 μm, it becomes difficult to obtain a dense fired body. More preferably, it is 10 micrometers or less, Most preferably, it is 5 micrometers or less. Typically 1 to 2 μm.

  When the glass powder of the high dielectric constant green sheet is desired to reduce the dielectric loss of the dielectric layers 12a and 13a or increase the mechanical strength, for example, cercian crystals and hexacells when fired at 900 ° C. It is preferable to deposit at least one of cyan crystals.

The glass powder of the high dielectric constant green sheet is expressed in terms of mol% based on the following oxides: SiO ₂ 20 to 75%, B ₂ O ₃ + MgO + ZnO 3 to 60%, Al ₂ O ₃ + CaO + SrO + BaO + TiO ₂ + ZrO ₂ + SnO ₂ 5 It preferably consists essentially of ˜60%, Y ₂ O ₃ + RE ₂ O ₃ + Nb ₂ O ₅ + Ta ₂ O ₅ 0-30%. Here, RE is a rare earth element. In the following, the glass composition is expressed as mol%, and mol% is simply expressed as%.

The said preferable aspect of the glass powder of a high dielectric constant green sheet is demonstrated.
SiO ₂ is a glass network former and is essential. If it is less than 20%, the glass becomes unstable. Preferably it is 25% or more. If it exceeds 75%, _TG becomes high. Preferably it is 65% or less, More preferably, it is 40% or less.
B ₂ O ₃ , MgO, and ZnO are components that lower the melting temperature or _TG of the glass, and must contain at least one of them. If the total content of these three components is less than 3%, it becomes difficult to obtain glass or _TG becomes high. Preferably it is 5% or more, More preferably, it is 15% or more. If it exceeds 60%, the glass becomes unstable. Preferably it is 45% or less.

Al ₂ O ₃ , CaO, SrO, BaO, TiO ₂ , ZrO ₂ and SnO ₂ are components that stabilize the glass or increase the chemical durability, and must contain at least one of them. If the total content of these seven components is less than 5%, the glass becomes unstable or the chemical durability becomes low. Preferably it is 8% or more. If it exceeds 60%, it becomes difficult to obtain glass. Preferably it is 40% or less.
Y ₂ O ₃ , RE ₂ O ₃ , Nb ₂ O ₅ and Ta ₂ O ₅ are not essential, but may be contained up to 30% in total in order to increase ε. If it exceeds 30%, the glass becomes unstable. Preferably it is 20% or less.

The glass powder of this preferred embodiment consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired. When such components are contained, the total content is preferably 10% or less, more preferably 5% or less.
Examples of the other components include components for reducing the glass melting temperature such as P ₂ O ₅ , Li ₂ O, Na ₂ O, K ₂ O, etc., CuO, CoO, Bi ₂ O ₃ , WO _{3 and the} like. Examples of the glass coloring component or the crystallization control component.
In _the case of containing Li 2 O, Na ₂ O or _{K 2} O, it is preferable that the total content of these components is less than 1%. If it is 1% or more, the dielectric loss may increase, or the electrical insulation property may decrease. It is preferable not to contain these alkali metal oxides when it is desired to further reduce the dielectric loss or increase the electrical insulation.
Moreover, it is preferable not to contain PbO substantially.

When it is desired to increase ε of the dielectric layers 12a and 13a, the ceramic powder of the high dielectric constant green sheet is a composite oxide containing Ba and Ti and having a Ti / Ba molar ratio of 3.5 to 5.5. It is preferable to contain this powder. Examples of the composite oxide include BaTi ₄ O ₉ and Ba ₂ Ti ₉ O _20, but it is preferable to use a BaTi ₄ O ₉ powder in order to obtain a denser fired body.

As a preferable aspect of the inorganic content of the high dielectric constant green sheet, it is essentially composed of 25 to 75% lead-free glass powder and 25 to 75% BaTi ₄ O ₉ powder in mass percentage, and the lead-free glass powder is based on the following oxide standards SiO ₂ 20-40%, B ₂ O ₃ 5-37%, Al ₂ O ₃ 2-15%, CaO + SrO 1-15%, BaO 5-25%, ZnO 0-35%, TiO Examples thereof include glass ceramic compositions consisting essentially of ₂ + ZrO ₂ + SnO ₂ 0 to 10%, and B ₂ O ₃ + ZnO of 15 to 45%.

The components of the lead-free glass powder will be described.
SiO ₂ is a glass network former and is essential. If it is less than 20%, it is difficult to obtain a stable glass. Preferably it is 25% or more, more preferably 30% or more. If it exceeds 40%, _TG may be too high, or ε may be small. Preferably it is 38% or less, More preferably, it is 35% or less.

B ₂ O ₃ is a component that lowers _TG or stabilizes glass, and is essential. If it is less than 5%, the glass tends to be unstable. Preferably it is 10% or more, More preferably, it is 15% or more. If it exceeds 37%, the chemical durability of the glass powder decreases. Preferably it is 30% or less, More preferably, it is 25% or less, More preferably, it is 22% or less.

ZnO is not essential, but may be contained up to 35% in order to lower _TG . If it exceeds 35%, the chemical durability, particularly acid resistance, of the glass is lowered. Preferably it is 20% or less. When ZnO is contained, the content is preferably 2% or more. If it is less than 2%, the effect may be insufficient. Preferably it is 5% or more, More preferably, it is 10% or more.
_Further, it is preferable that B ₂ O 3 + ZnO is 15 to 45%. If B ₂ O ₃ + ZnO is less than 15%, _TG may increase. If it exceeds 45%, the chemical durability decreases.

Al ₂ O ₃ is a component that increases the stability or chemical durability of glass and is essential. If it is less than 2%, the glass becomes unstable. Preferably it is 5% or more. If it exceeds 15%, _TG becomes too high. Preferably it is 10% or less.

BaO is a component that stabilizes the glass and is essential. If it is less than 5%, the glass becomes unstable, or the BaTi ₄ O ₉ crystal reacts with the glass powder during firing to reduce the content of the BaTi ₄ O ₉ crystal in the fired body, thereby reducing ε. . Preferably it is 10% or more, more preferably 13% or more. If it exceeds 25%, the glass may become unstable.
CaO and SrO are components that stabilize the glass and lower the tan δ of the fired body, and need to be 1% or more alone or in total. If it is less than 1%, the tan δ of the fired product may increase. Preferably it is 5% or more. If it exceeds 15%, the ε of the fired product decreases. Preferably it is 10% or less.

TiO ₂ , ZrO _2, and SnO ₂ are not essential, but may be contained up to 10% in total for the purpose of increasing the chemical durability of glass, accelerating the precipitation of crystals, increasing the amount of precipitation, etc. . If it exceeds 10%, _TG may be increased, or the denseness of the fired product may be decreased.
The lead-free glass powder consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired. When other components are contained, the total content is preferably 10% or less, more preferably 5% or less. PbO is not contained.

The glass ceramic composition consists essentially of the lead-free glass and BaTi ₄ O ₉ powder. In addition, for example, Ba ₂ Ti ₉ O ₂₀ , MgO, BaWO ₄ , ZrO ₂ , MgTiO ₃ , CaTiO ₃ , SrTiO _3. One or more crystal (ceramics) powders selected from the group consisting of TiO ₂ and 0.1 to 10% in total may be contained. These powders are contained for the purpose of reducing the temperature dependence of the relative dielectric constant of the fired body, and hence the temperature dependence of the antenna characteristics, adjusting the precipitated crystals, and adjusting the expansion coefficient of the fired body.

  When it is desired to increase the mechanical strength of the dielectric layers 12b and 13b, the glass powder of the low dielectric constant green sheet, for example, celsian, hexacelsian, garnite, forsterite, enstar when fired at 900 ° C. It is preferable to deposit one or more types of crystals (ceramics) selected from the group consisting of tight, diopside and ananosite. When it is desired to further reduce the dielectric loss, it is more preferable to deposit one or more kinds of crystals selected from the group consisting of celsian, forsterite, enstatite and diopside.

The glass powder of the low dielectric constant green sheet is SiO ₂ 20 to 75%, B ₂ O ₃ + MgO + ZnO 3 to 60%, Al ₂ O ₃ + CaO + SrO + BaO + TiO ₂ + ZrO ₂ + SnO ₂ 5-60 in terms of mol% based on the following oxides. %, Preferably consisting essentially of
This preferred composition is described below.
SiO ₂ is a glass network former and is essential. If it is less than 20%, the glass becomes unstable. Preferably it is 25% or more. If it exceeds 75%, _TG becomes high. Preferably it is 65% or less, More preferably, it is 55% or less.

B ₂ O ₃ , MgO, and ZnO are components that lower the melting temperature or _TG of the glass, and must contain at least one of them. If the total content of these three components is less than 3%, it becomes difficult to obtain glass or _TG becomes high. Preferably it is 5% or more, More preferably, it is 15% or more. If it exceeds 60%, the glass becomes unstable. Preferably it is 45% or less.
Al ₂ O ₃ , CaO, SrO, BaO, TiO ₂ , ZrO ₂ and SnO ₂ are components for stabilizing the glass or increasing the chemical durability, and must contain at least one of them. Don't be. If the total content of these seven components is less than 5%, the glass becomes unstable or the chemical durability becomes low. Preferably it is 8% or more. If it exceeds 60%, the glass is rather unstable. Preferably it is 40% or less.

Although the glass powder of the said preferable composition consists essentially of the said component, you may contain another component in the range which does not impair the objective of this invention. When such components are contained, the total content is preferably 10% or less, more preferably 5% or less.
Examples of the other components include MgO, P ₂ O ₅ , Li ₂ O, Na ₂ O, K ₂ O and other components intended to lower the glass melting temperature, CuO, CoO, Bi ₂ O ₃ , WO ₃ , glass coloring components such as CeO ₂ , Y ₂ O ₃ , La ₂ O ₃ , Nd ₂ O ₃ , Sm ₂ O ₃ or the like, and crystal precipitation control components.

In _the case of containing Li 2 O, Na ₂ O or _{K 2} O, it is preferable that the total content of these components is less than 1%. If it is 1% or more, the dielectric loss may increase, or the electrical insulation property may decrease. It is preferable not to contain these alkali metal oxides when it is desired to further reduce the dielectric loss or increase the electrical insulation.
Moreover, it is preferable not to contain PbO substantially.

When it is desired to increase the mechanical strength of the dielectric layers 12b and 13b, or to adjust the expansion coefficient of the fired body (dielectric layer), the ceramic powder of the low dielectric constant green sheet is composed of alumina, mullite, silica, One or more ceramic powders selected from the group consisting of forsterite, spinel and cordierite are preferred. From the viewpoint of improving the mechanical strength, it is preferable to use alumina powder.
_{D 50} of the powder of the one or more ceramics is preferably 1～12Myuemu. If it is less than 1 μm, it may be difficult to uniformly disperse the powder in the green sheet, or the mechanical strength of the fired body (dielectric layer) may be reduced. More preferably, it is 1.5 μm or more. If it exceeds 12 μm, it becomes difficult to obtain a dense fired product. More preferably, it is 10 μm or less, particularly preferably 5 μm or less, and most preferably 3.5 μm or less.

As a preferred embodiment of the inorganic content of the low dielectric constant green sheet, it is essentially composed of 35 to 65% lead-free glass powder and 35 to 65% alumina powder in terms of mass percentage, and the lead-free glass powder is mol% based on the following oxides. in _{view, SiO 2 20~40%, B 2} O 3 5~37%, Al 2 O 3 2~15%, CaO + SrO 1~20%, BaO 5~25%, ZnO 0~35%, TiO 2 + ZrO 2 A glass ceramic composition consisting essentially of + SnO ₂ 0 to 5% and B ₂ O ₃ + ZnO of 15 to 45% is exemplified. For example, ε and tan δ of a fired body (dielectric) obtained by firing the glass ceramic composition at 900 ° C. are 5 to 8 and 0.0010 to 0.0030, respectively.

The components of the lead-free glass powder will be described.
SiO ₂ is a glass network former and is essential. If it is less than 20%, it is difficult to obtain a stable glass. Preferably it is 25% or more, more preferably 30% or more. If it exceeds 40%, _TG may be too high. Preferably it is 38% or less, More preferably, it is 35% or less.
B ₂ O ₃ is a component that stabilizes the glass and is essential. If it is less than 5%, the glass tends to be unstable. Preferably it is 10% or more, More preferably, it is 15% or more. If it exceeds 37%, the chemical durability of the glass powder decreases. Preferably it is 30% or less, More preferably, it is 25% or less, More preferably, it is 22% or less.

ZnO is not essential, but may be contained up to 35% in order to lower _TG . If it exceeds 35%, the chemical durability, particularly acid resistance, of the glass is lowered. Preferably it is 20% or less. When ZnO is contained, the content is preferably 2% or more. If it is less than 2%, the effect may be insufficient. Preferably it is 5% or more, More preferably, it is 10% or more.
_Further, it is preferable that B ₂ O 3 + ZnO is 15 to 45%. If B ₂ O ₃ + ZnO is less than 15%, _TG may increase. If it exceeds 45%, the chemical durability decreases.

Al ₂ O ₃ is a component that increases the stability or chemical durability of glass and is essential. If it is less than 2%, the glass becomes unstable. Preferably it is 5% or more. If it exceeds 15%, _TG becomes too high. Preferably it is 10% or less.
BaO is a component that stabilizes the glass and is essential. If it is less than 5%, the effect is insufficient. Preferably it is 10% or more, more preferably 13% or more. If it exceeds 25%, the glass may become unstable.

CaO and SrO are not essential, but are components that stabilize the glass and lower the tan δ of the fired body, and need to be 1% or more alone or in total. If it is less than 1%, the tan δ of the fired product may increase. Preferably it is 5% or more. If it exceeds 20%, the glass is rather unstable. Preferably it is 15% or less, More preferably, it is 10% or less.
TiO ₂ , ZrO ₂ , and SnO ₂ are not essential, but may be incorporated up to a total of 5% in order to increase the chemical durability of the glass, accelerate the precipitation of crystals, increase the amount of precipitation, and the like. . If it exceeds 5%, ε or _TG may be increased, or the compactness of the fired product may be reduced.

The lead-free glass powder consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired. When other components are contained, the total content is preferably 10% or less, more preferably 5% or less.
Examples of the other components include MgO, P ₂ O ₅ , Li ₂ O, Na ₂ O, K ₂ O and other components intended to lower the glass melting temperature, CuO, CoO, Bi ₂ O ₃ , WO ₃ , glass coloring components such as CeO ₂ , Y ₂ O ₃ , La ₂ O ₃ , Nd ₂ O ₃ , Sm ₂ O ₃ or the like, and crystal precipitation promoting components.

In _the case of containing Li 2 O, Na ₂ O or _{K 2} O, it is preferable that the total content of these components is less than 1%. If it is 1% or more, the dielectric loss may increase, or the electrical insulation property may decrease. It is preferable not to contain these alkali metal oxides when it is desired to further reduce the dielectric loss or increase the electrical insulation.
Moreover, PbO is not contained.

  The glass ceramic composition consists essentially of the lead-free glass and alumina powder. In addition, for example, ceramics such as celsian, hexacelsian, cordierite, and magnesium titanate are used for controlling the thermal expansion coefficient. In order to prevent color development of the powder and the portion in contact with the silver conductor, cerium oxide powder, etc. may be contained in a total range of 0.1 to 15%.

As another preferred embodiment of the low dielectric constant green sheet inorganic content in the case where it is desired to increase the mechanical strength, to reduce the firing shrinkage rate or the dimensional variation in the plane direction, etc., a lead-free glass powder having a mass percentage display of 40 to 90% And lead-free glass powder in terms of mol% based on the following oxide standards, SiO ₂ 35 to 55%, B ₂ O ₃ 0 to 5%, Al ₂ O ₃ 5 to 5%. A glass ceramic composition consisting essentially of 20%, MgO 20-40%, CaO 0-20%, BaO 0-10%, ZnO 0-10%, TiO ₂ + ZrO ₂ + SnO ₂ 0-10% is exemplified. The
For example, ε and tan δ of a fired body (dielectric) obtained by firing the glass ceramic composition at 900 ° C. are 5 to 8 and 0.0010 to 0.0030, respectively.

When the low dielectric constant green sheet having the inorganic content of this preferred embodiment and the high dielectric constant green sheet having the inorganic content of the preferred embodiment are used as the low dielectric constant green sheet and the high dielectric constant green sheet, respectively, the low dielectric constant green sheet preferably higher than T _G is T _G of a glass powder having a high dielectric constant green sheet of glass powder, the difference between the two T _G is preferably 50 ° C. or higher, more preferably 100 ° C. or higher, particularly preferably 120 ° C. or higher It is.

Next, the components of the lead-free glass powder will be described.
SiO ₂ is a glass network former and is essential. If it is less than 35%, it is difficult to obtain a stable glass. Preferably it is 40% or more, more preferably 42% or more. If it exceeds 55%, _TG may be too high. Preferably it is 52% or less.
B ₂ O ₃ is not essential, but may be incorporated up to 5% in order to lower the melting temperature or _TG of the glass. If it exceeds 5%, the tan δ of the fired product may be increased, or the chemical durability may be lowered.

MgO is a component that stabilizes the glass, lowers the melting temperature of the glass, or promotes crystal precipitation from the glass, and is essential. If it is less than 20%, the effect is insufficient. Preferably it is 25% or more. If it exceeds 40%, the glass becomes unstable. Preferably it is 38% or less.
ZnO is not essential, but may be contained up to 10% in order to reduce _TG . If it exceeds 10%, the chemical durability, particularly acid resistance, of the glass is lowered. Preferably it is 8% or less. When ZnO is contained, the content is preferably 2% or more. If it is less than 2%, the effect may be insufficient. Preferably it is 5% or more.
Al ₂ O ₃ is a component that increases the stability or chemical durability of glass and is essential. If it is less than 5%, the glass becomes unstable. Preferably it is 6% or more. If it exceeds 20%, _TG becomes too high. Preferably it is 10% or less, More preferably, it is 8.5% or less.

  CaO is not essential, but it is a component that stabilizes the glass and lowers tan δ of the fired body, and can be contained up to 20%. Further, it is a constituent component of diopside and anorthite, and when it is desired to precipitate these crystals, it is preferably at least 5%, more preferably at least 7%. When it is desired to precipitate anorthite, it is preferably 14% or more. If it exceeds 20%, the glass may become unstable. Preferably it is 18% or less. When it is not desired to deposit anorthite, it is preferably 12% or less.

BaO is not essential, but is a component that stabilizes the glass, and can be contained up to 10%. If it exceeds 10%, the tan δ of the fired product may be increased.
TiO ₂ , ZrO ₂ , and SnO ₂ are not essential, but may be contained up to a total of 10% in order to increase the chemical durability of the glass or the crystallization rate of the fired body. If it exceeds 10%, the softening point of the glass tends to be high, or the denseness of the fired product may be reduced.

This lead-free glass powder consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired. When other components are contained, the total content is preferably 10% or less.
For example, components such as P ₂ O ₅ , Li ₂ O, Na ₂ O, and K ₂ O are used for the purpose of lowering the glass melting temperature, and CuO and CoO are used for the purpose of coloring the glass and increasing the crystallization rate. , CeO ₂ , Y ₂ O ₃ , La ₂ O ₃ , Nd ₂ O ₃ , Sm ₂ O ₃ , Bi ₂ O ₃ , WO _{3 and the} like can be contained. When it contains any of Li ₂ O, Na ₂ O, and K ₂ O, the total content of these components is preferably less than 1%.
Moreover, PbO is not contained.

(Example 1)
The mol% display composition is SiO ₂ 31.7%, B ₂ O ₃ 21.5%, ZnO 15.4%, Al ₂ O ₃ 6.5%, CaO 7.4%, BaO 14.7%, ZrO. ₂ Raw materials were prepared and mixed so that a glass (T _G = 603 ° C.) that was 2.0% and SnO ₂ 0.6% was obtained, and the mixed raw materials were placed in a platinum crucible and heated at 1550 ° C. for 60%. After melting for a minute, the molten glass was poured out and cooled.
The obtained glass was pulverized with an alumina ball mill for 32 hours to obtain a glass powder (D ₅₀ = 3.6 μm). In addition, ethyl alcohol was used as a solvent for pulverization.

On the other hand, BaTi ₄ O ₉ powder was produced as follows. That is, 88 g of BaCO ₃ (barium carbonate BW-KT manufactured by Sakai Chemical Industry Co., Ltd.) and 130 g of TiO ₂ (reagent rutile type manufactured by Kanto Chemical Co., Ltd.) were mixed in a ball mill using water as a solvent. For 2 hours. Trituration with cooled ball mill for 60 hours to obtain a powder _{D 50} is 0.9 .mu.m. When X-ray diffraction measurement was performed on this powder, a strong diffraction peak pattern of BaTi ₄ O ₉ crystals was observed, confirming that this powder was BaTi ₄ O ₉ powder.

Next, the glass powder 38%, BaTi ₄ O ₉ powder 58%, MgTiO ₃ powder (magnesium titanate powder MT manufactured by Fuji Titanium Industry Co., Ltd.) 2%, TiO ₂ powder (Titanium oxide manufactured by Sakai Chemical Industry Co., Ltd.) in mass percentage display. A mixed powder H (glass ceramic composition) composed of 2% of powder SR1) was produced.

  1. 50 g of mixed powder H and 15 g of organic solvent (toluene, xylene, 2-propanol, 2-butanol mixed at a mass ratio of 4: 2: 2: 1), plasticizer (di-2-ethylhexyl phthalate) 5 g of resin (polyvinyl butyral PVK # 3000K manufactured by Denka) and 0.3 g of a dispersant (BYK180 manufactured by BYK Chemie) were mixed to form a slurry. The obtained slurry was applied on a PET film using a doctor blade method and dried to produce a high dielectric constant green sheet having a thickness of about 0.2 mm.

  On the other hand, 3 g mixed powder H was press-molded using a cylindrical mold, fired by holding at 860 ° C. for 1 hour, and then polished to prepare a cylindrical sample having a diameter of 8 mm and a thickness of 5 mm. . With respect to this sample, the relative dielectric constant at 10 GHz was measured by using a network analyzer (8722ES manufactured by Agilent Technologies) and a parallel conductor resonance method dielectric constant measuring system manufactured by Keycom, and found to be 22.7. Furthermore, a high dielectric constant green sheet was laminated and fired, and the obtained dielectric was measured for relative permittivity at 1 MHz, that is, ε using an LCR meter.

  Moreover, the mixed powder L which consists of 45% of the said glass powder and 55% of alumina powder (Sumitomo Chemical Co., Ltd. AA2) by mass percentage display was produced. A low dielectric constant green sheet having a thickness of about 0.2 mm was produced in the same manner as the method for producing a high dielectric constant green sheet except that the mixed powder L was used instead of the mixed powder H.

  The relative dielectric constant at 25 GHz of the fired product obtained by firing this low dielectric constant green sheet was measured as follows. That is, this low dielectric constant green sheet was cut to produce 6 sheets of 50 mm × 50 mm, and these were laminated and pressed by pressing at 15 MPa for 1 minute. The obtained press-bonded press product was held at 550 ° C. for 5 hours to decompose and remove the resin component, and then fired at 860 ° C. for 1 hour to prepare a fired body. The obtained fired body was mirror-polished on both upper and lower surfaces to prepare a sample having a thickness of 250 μm. With respect to this sample, the relative dielectric constant at 25 GHz was measured using the network analyzer and 25 GHz cavity resonator, and found to be 7.6. Further, when ε was measured in the same manner as previously performed on the high dielectric constant green sheet fired body, it was 7.6.

  Next, the high dielectric constant and low dielectric constant green sheets obtained as described above were cut to produce 4 sheets each of 40 mm × 40 mm, for a total of 8 sheets. Two green sheets (the unfired dielectric layer 12β), two high dielectric constant green sheets (the unfired dielectric layer 12α), two high dielectric constant green sheets (the unfired dielectric layer 13α), low dielectric Two green sheets (rate of unfired dielectric layer 13β) were laminated in this order.

  Of the eight green sheets, four green sheets of the unfired dielectric layers 12β and 12α were formed with silver paste filled holes that should be fired to become the vias 20 of the antenna element 10. That is, a diameter of 0.15 mm is formed at a position where the via 20 is to be formed by firing the green sheet (position to be 0.9 mm after firing from one end on the center line of the portion to be the antenna element 10 after firing). A punch hole was opened, and a silver paste filling hole was formed by embedding a silver paste in the punch hole.

Further, among the two high dielectric constant green sheets of the unfired dielectric layer 13α, the green sheet on the side close to the unfired dielectric layer 12α is fired onto the radiation conductor 11 and the feed line 14 on the surface on the near side. The silver paste pattern to be formed was formed by screen printing.
The silver paste pattern to be baked to become the radiation conductor 11 was the same as the pattern of the radiation conductor 11 in FIG. That is, the silver paste pattern has one symmetry axis, and the symmetry axis is located on the green sheet central axis. The diameter of the circle that overlaps the semi-ellipse is 8 mm, and the center thereof is located at a position of 7.6 mm after firing from one end of the portion of the symmetrical axis that should be the antenna element 10 after firing. The semi-ellipse overlapping the circle has a major axis radius of 6 mm, a minor axis radius of 1 mm, and the center of the original ellipse is positioned 1.6 mm from one end of the portion of the symmetry axis that should become the antenna element 10 after firing.
The silver paste pattern to be baked to form the feeder line 14 has a symmetrical axis portion (length: 0.9 mm) from a position 0.8 mm away from one end of the symmetrical axis to a position 1.7 mm away from the same end. It is formed in a strip shape having a width of 0.2 mm, and is connected to a silver paste pattern that is baked to become the radiation conductor 11.

Of the two low dielectric constant green sheets of the unfired dielectric layer 12β, the surface of the green sheet to be in contact with the insulating substrate 17 of the green sheet to be in contact with the insulating substrate 17 is fired and ground patterns 15 and 15 and the power supply pad A silver paste pattern to be (not shown in FIGS. 1 and 2) was formed by screen printing.
The silver paste pattern to be the power supply pad is a rectangle having a length of 1.1 mm in the direction of the symmetry axis (radial conductor axis direction) and a length of 1.4 mm in the direction orthogonal to the same direction, and the center thereof is the via 20. It is located on the central axis of the silver paste filling hole to be. The power supply pad is connected to the via 20.
Each of the silver paste patterns to be the ground patterns 15 and 15 is a rectangle having a symmetrical axis direction length of 1.0 mm and a length of 2.5 mm in the direction orthogonal to the same direction, It is in a symmetric position across the symmetry axis, and the distance from the symmetry axis is 2.45 mm. Further, the center of both patterns and the center of the silver paste pattern to be the power supply pad are located on the same line.

A laminate of the 8 green sheets was thermocompression bonded at 80 ° C. for 5 minutes. The obtained thermocompression-bonded product was held at 550 ° C. for 5 hours to decompose and remove the resin component, and then fired at 860 ° C. for 1 hour to produce a fired body.
The fired body thus obtained was cut with a precision cutting machine so that the length in the direction of the symmetric axis was 12 mm and the length in the direction perpendicular to the same direction was 10 mm, whereby the antenna element 10 was obtained. The dielectric layers 12a, 12b, 13a, 13b all had a thickness of 0.3 mm, and the antenna element 10 had a thickness of 1.2 mm. The effective dielectric constants at 1 MHz of the dielectric bodies 12 and 13 are both 15.2.

On the other hand, a double-sided copper-clad resin substrate having a size of 40 mm × 30 mm (R-1766T manufactured by Matsushita Electric Works, Ltd. The resin has a relative dielectric constant at 1 GHz of 4.7, a resin part thickness of 0.8 mm, and a copper foil thickness of 0 .018 mm.) Was etched to produce an insulating substrate 17 having a ground conductor 18 and an exposed portion 24 on the bottom surface and a signal line 19 on the top surface.
The size of the ground conductor 18 is 27 mm × 30 mm, and is formed in a region of 27/40 in the longitudinal direction of the insulating substrate 17. The size of the exposed portion 24 is 13 mm × 30 mm.
The signal line 19 is a microstrip line having a length of 27 mm and a width of 0.9 mm. The signal line 19 extends perpendicularly from one of the short sides of the insulating substrate 17, and the distance from the long side is 5.3 mm.
Note that two bonding pads (not shown in FIG. 2) to be in contact with the ground patterns 15 and 15 are provided on the upper surface of the insulating substrate 17, and vias (in FIG. 2) for electrically connecting the pads and the ground conductor 18. Two pieces (not shown) are formed inside the insulating substrate 17.

The conductors such as the ground conductor 18, the signal line 19, and the bonding pad were subjected to a gold flash process, and then the portions other than the bonding pad were covered with a solder resist.
Next, lead-free cream solder (M705 manufactured by Senju Metal Co., Ltd.) is printed so as to cover the bonding pads using a metal mask, antenna patterns 15 and 15 are placed thereon, and power supply pads are placed on the signal lines 19. The antenna element 10 was placed so as to be placed, and then heated to 250 ° C. to fix the antenna element 10 to the upper surface of the insulating substrate 17 (welding and joining with solder). The distance between the circumference of the antenna element 10 and the long and short sides of the insulating substrate 17 was 1 mm.

FIG. 3 shows the results of measuring the VSWR of the antenna thus obtained at 1 to 12 GHz using a network analyzer. The _{results, f H = 11.8GHz, f L} = 2.9GHz, it can be seen that a Delta] f = 120%.

(Example 2)
The VSWR was calculated by electromagnetic field simulation by the FDTD method for an antenna having the same structure as the antenna obtained in Example 1 but having the same structure as shown in FIGS. The results are shown in FIG. 4, and it can be seen from this that Δf = 112%.

The difference between Example 2 and Example 1 is as follows.
The ε of the dielectric layers 12a and 13a is 22.7, which is the same as in Example 1. However, the ε of the dielectric layers 12b and 13b is 6.6.
The size of the antenna element 10 was 12 mm × 12 mm.
The feeding line 14 is formed in a strip shape having a width of 0.2 mm in a symmetrical axis portion (length: 0.9 mm) from a position 0.7 mm away from one end of the symmetry axis to a position 1.8 mm away from the same end. The radiation conductor 11 was connected.
The power supply pad has a rectangular shape with a symmetric axis length of 1.0 mm and a length perpendicular to the same direction of 0.9 mm, and the center thereof is located on the central axis of the via 20.
Each of the ground patterns 15 and 15 is a rectangle having a symmetric axis direction length of 1.0 mm and a length in a direction orthogonal to the same direction of 0.7 mm, and the center of both patterns sandwiches the symmetric axis. The distance from the symmetry axis at the symmetrical position was 2.7 mm.

The insulating substrate 17 had an ε of 4.4, a length in the direction of the axis of symmetry of 32 mm, and a length in the direction perpendicular to the same direction of 20 mm.
The size of the ground conductor 18 was 20 mm × 20 mm, and the size of the exposed portion 24 was 12 mm × 20 mm.
The signal line 19 is a microstrip line having a length of 20 mm and a width of 0.9 mm, extending perpendicularly from one of the short sides of the insulating substrate 17 and having a distance from the long side of 5.55 mm.

(Example 3)
The VSWR was calculated by the electromagnetic field simulation by the FDTD method for the antenna different from the antenna of Example 2 in the following points. The results are shown in FIG. 4, and it can be seen from this that Δf = 97%.
The difference between Example 3 and Example 2 is as follows.
In Example 2, the dielectrics 12 and 13 are both composed of two dielectric layers (12 is 12a and 12b, 13 is 13a and 13b), but the dielectrics 12 and 13 in Example 3 are both one layer. Each dielectric layer has an ε of 22.7.

(Example 4)
The VSWR was calculated by electromagnetic field simulation by the FDTD method for the antenna different from the antenna of Example 3 in the following points. The results are shown in FIG. 4, and it can be seen from this that Δf = 93%.
The difference between Example 4 and Example 3 is as follows.
The dielectrics 12 and 13 of Example 3 both have ε of 22.7, while the dielectrics 12 and 13 of Example 4 both have ε of 14.0.

Sectional drawing in the same figure straight line AB of the antenna of this invention shown with a top view in FIG. The top view of the antenna of this invention. The VSWR frequency characteristic figure of the antenna (Example 1) of this invention. The VSWR frequency characteristic figure of the antenna (Example 2, 3, 4) of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Antenna 10: Antenna element 11: Radiation conductor 12, 13: Dielectric 12a, 12b, 13a, 13b: Dielectric layer 14: Feed line 15: Ground pattern 17: Insulating substrate 18: Ground conductor 19: Signal line 20 : Via 24: Exposed part

Claims (13)

An axisymmetric planar radiating conductor whose both surfaces are covered with a dielectric is formed on one surface of the insulating substrate, and a ground conductor is formed on the inside of the substrate or on the other surface where the radiating conductor is not formed . Any of dielectrics covering both surfaces of an axially symmetric planar radiating conductor, which is an antenna, has two or more dielectric layers having a relative dielectric constant of 5 to 40 at 1 MHz and different relative dielectric constants. Of the adjacent dielectric layers, the relative dielectric constant of the dielectric layer closer to the radiating conductor is larger than the relative dielectric constant of the dielectric layer further away from the radiating conductor, and covers both sides of the radiating conductor. antenna the effective dielectric constant that put in to have dielectric 1MHz of is 8 to 18. The antenna according to claim 1, wherein a specific bandwidth at 1 to 30 GHz is 10% or more. The antenna according to claim 2 wherein the radiating conductor symmetry axis direction length of the ground conductor is under 35mm or less.   The antenna according to claim 3, wherein the length of the dielectric covering the axially symmetric planar radiating conductor in the radiating conductor symmetric axis direction is 20 mm or less.   The antenna according to claim 3 or 4, wherein a length of the ground conductor in a direction orthogonal to the axis of symmetry of the radiation conductor is 36 mm or less. Each of the dielectrics covering both surfaces of the axially symmetric planar radiating conductor is composed of two dielectric layers, and the dielectric layer closer to the radiating conductor has a relative permittivity at 1 MHz of 11 to 35, and the radiating conductor. The antenna according to any one of claims 1 to 5, wherein a dielectric constant at 1 MHz of a dielectric layer farther from the antenna is 5 to 15. 7. The method of manufacturing an antenna according to claim 6 , wherein the glass powder-containing high dielectric constant green sheet to be fired to become a dielectric layer having a relative dielectric constant of 11 to 35 and the fired relative dielectric constant of 5 to 15 are obtained. The required number of glass powder-containing low-dielectric constant green sheets to be the dielectric layer is prepared, and a conductive paste pattern to be baked to become an axisymmetric planar radiation conductor is formed on one surface of each of the green sheets. Then, these green sheets are laminated and fired to produce a dielectric-covered axisymmetric planar radiating conductor, and the dielectric-covered axisymmetric planar radiating conductor has a ground conductor formed inside or on one side. A method for manufacturing an antenna, comprising fixing an insulating substrate to a surface on which a ground conductor is not formed. Assuming that the inorganic content of the glass powder-containing high dielectric constant green sheet consists essentially of 30 to 90% glass powder and 10 to 70% ceramic powder in terms of mass percentage, and the rare earth element is represented by RE, the glass powder is: SiO ₂ 20-75%, B ₂ O ₃ + MgO + ZnO 3-60%, Al ₂ O ₃ + CaO + SrO + BaO + TiO ₂ + ZrO ₂ + SnO ₂ 5-60%, Y ₂ O ₃ + RE ₂ O ₃ + Nb _The method for manufacturing an antenna according to claim 7 , consisting essentially of ₂ O ₅ + Ta ₂ O ₅ 0-30%. 9. The method for manufacturing an antenna according to claim 8 , wherein the ceramic powder contains a complex oxide powder containing Ba and Ti and having a Ti / Ba molar ratio of 3.5 to 5.5. The glass powder-containing high dielectric constant green sheet has an inorganic content of 25 to 75% lead-free glass powder and 25 to 75% BaTi in terms of mass percentage. ₄ O ₉ It consists essentially of powder, and the lead-free glass powder is SiO 2 ₂   20-40%, B ₂ O ₃   5-37%, Al ₂ O ₃   2-15%, CaO + SrO 1-15%, BaO 5-25%, ZnO 0-35%, TiO ₂ + ZrO ₂ + SnO ₂   Consisting essentially of 0-10%, B ₂ O ₃ The method for manufacturing an antenna according to claim 7, wherein + ZnO is 15 to 45%. The inorganic content of the glass powder-containing low dielectric constant green sheet is essentially composed of 30 to 90% glass powder and 10 to 70% ceramic powder in terms of mass percentage, and the glass powder is expressed in terms of mol% based on the following oxides. _{SiO 2 20~75%, B 2 O} 3 + MgO + ZnO 3~60%, of the antenna according to any one of _{Al 2 O 3 + CaO + SrO} + BaO + TiO 2 + ZrO 2 + SnO 2 5~60%, consisting essentially of claims 7 to 10 Production method. The antenna powder according to claim 11 , wherein the ceramic powder of the low dielectric constant green sheet containing glass powder is one or more ceramic powders selected from the group consisting of alumina, mullite, silica, forsterite, spinel and cordierite. Production method. The glass powder-containing low dielectric constant green sheet is essentially composed of 35 to 65% lead-free glass powder and 35 to 65% alumina powder in terms of mass percentage, and the lead-free glass powder is expressed in mol% based on the following oxides. And SiO ₂   20-40%, B ₂ O ₃   5-37%, Al ₂ O ₃   2-15%, CaO + SrO 1-20%, BaO 5-25%, ZnO 0-35%, TiO ₂ + ZrO ₂ + SnO ₂   Consisting essentially of 0-5%, B ₂ O ₃ The method for manufacturing an antenna according to claim 7, wherein + ZnO is 15 to 45%.

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