JP2010074255A - High-frequency filter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency filter device which is structured of dielectric substrates, and has a low loss and an attenuation pole. <P>SOLUTION: The high-frequency filter device includes laminated dielectric layers 1 and 2 and conductor layers 4 and 5, a plurality of shielding via conductors 8, termination via conductors 9, waveguides 12, strip conductors 6 and 7, and an input and output joint via conductor 10. Each of the plurality of shielding via conductors 8 is formed so that the conductor layers 4 and 5 may be short-circuited. The plurality of shielding via conductors 8 are arranged in two columns with mutual spacing of 1/2 signal wavelength or less and column spacing of 1/2 signal wavelength or more. The waveguides 12 are surrounded by the shielding via conductors 8 of two columns and the termination via conductors 9. The strip conductors 6 and 7 are formed on the surface of the dielectric layer 2. The input and output joint via conductor 10 is located in the waveguide 12 between the termination via conductors 9. One end of the input and output joint via conductor 10 is connected to the strip conductors 6 and 7 respectively through a penetrated hole 11 formed at the conductor layer 4, and the other end is connected to the waveguide 12. The resonance mode is excited at two waveguides 12-2 and 12-3 surrounded by the input and output joint via conductor 10, the termination via conductors 9, and the shielding via conductors 8 to produce the attenuation pole. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio apparatus using a high frequency signal such as a millimeter wave band and a filter apparatus used in a high frequency circuit for processing a high frequency signal such as a millimeter wave band.

  In a high-frequency communication system, a filter is an indispensable element. In a mobile communication system or the like, a narrow band filter is required for effective use of a frequency band. In mobile communication base stations, communication satellites, and the like, there is a strong demand for a filter that can withstand a large amount of power with a narrow band, a low loss and a small size. Further, in millimeter wave or quasi-millimeter wave wireless communication systems that have been developed in recent years, filters using hollow waveguides have been used in the past. However, there is a strong demand for filters that are small and have low loss. Yes.

  Some high-frequency circuit elements such as resonator filters currently used use a transmission line structure. A high-frequency circuit element using a transmission line structure is widely used because it is small in size and has a two-dimensional structure formed on a substrate and can be easily combined with other circuits and elements.

  In the millimeter wave band, etc., for the purpose of reducing the size of the hollow waveguide filter device, dielectric conductors composed of conductor layers formed on both surfaces of the dielectric substrate and via conductors that short-circuit the conductor layers are used. There is a filter device using a wave tube (see Patent Document 1). In addition, in a dielectric waveguide type filter device, there is a configuration in which a slot line resonator is provided in a conductor layer as a configuration for introducing an attenuation pole into a frequency characteristic (see Patent Document 2).

JP 2002-026611 A. Japanese Patent Laid-Open No. 2002-026610.

  However, the filter device using the transmission line structure is greatly affected by the conductor loss, and it is difficult to realize a filter device with low loss or steep characteristics when handling a high frequency signal such as a millimeter wave band.

  In a filter device having a dielectric waveguide structure, an effective method of exciting a resonance mode is a problem. For this reason, in Patent Document 1, a coplanar line is formed on one conductor layer, and the fundamental resonance mode and A coupling configuration is described. In addition, since a plurality of resonators excited only in the fundamental mode are coupled to form a filter device, loss due to via conductors at the coupling portion between resonators also occurs.

  Further, in the configuration of Patent Document 1, the input / output coupling degree is determined by the relative positional relationship between the conductor pattern and the via conductor. However, in general, the relative positional accuracy between the conductor pattern and the via conductor is affected by the overlay error of each layer during the manufacture of the multilayer board as a problem in the production of the multilayer board. It is considerably worse than the relative position accuracy. Therefore, in the configuration of Patent Document 1, there is a problem that the yield in manufacturing decreases due to the influence of manufacturing errors.

  Furthermore, in the filter device using the waveguide structure, a steep attenuation characteristic can be obtained by the waveguide cutoff on the lower frequency side than the desired passband, but the propagation mode always exists on the higher frequency side. It is difficult to obtain a steep attenuation characteristic.

  In order to solve such a problem, in the configuration of Patent Document 2 in which the slot line resonator is provided in the conductor layer, it is difficult to obtain a steep attenuation pole due to the influence of the conductor loss in the slot line resonator.

  The present invention has been made in view of the above problems, and provides a low-loss high-frequency filter device that has a simple configuration, is hardly affected by manufacturing errors, and can easily obtain a steep attenuation pole. Objective.

The high frequency filter device according to the first aspect of the present invention is a high frequency filter device in which at least one resonator is formed in a waveguide structure configured by laminating a plurality of dielectric layers,
A first dielectric layer and a pair of opposing first and second conductor layers formed on both sides of the dielectric layer;
A plurality of the first and second conductor layers are formed so as to be short-circuited, and are arranged in two rows with a mutual interval of 1/2 or less of the signal wavelength and a column interval of 1/2 or more of the signal wavelength. A shielding via conductor of
A waveguide portion surrounded by the two rows of shield via conductors and termination via conductors installed at two locations between the two rows of shield via conductors;
A second dielectric layer formed on the surface of the first conductor layer;
A pair of strip conductors formed on the surface of the second dielectric layer;
Located in the waveguide portion between the terminal via conductors installed at the two locations, through the opening formed in the first conductor layer, one end is respectively connected to the pair of strip conductors, An input coupling via conductor and an output coupling via conductor, the other end of which is connected to the waveguide portion, and
Resonance excited by two waveguide portions surrounded by the input coupling via conductor, the termination via conductor, the shielding via conductor, and the output coupling via conductor, the termination via conductor, and the shielding via conductor. The mode is characterized by producing an attenuation pole.

The high frequency filter device according to the second aspect of the present invention is a high frequency filter device in which at least one resonator is formed in a waveguide structure configured by laminating a plurality of dielectric layers,
A first dielectric layer and a pair of opposing first and second conductor layers formed on both sides of the first dielectric layer;
A plurality of the first and second conductor layers are formed so as to be short-circuited, and are arranged in two rows with a mutual interval of 1/2 or less of the signal wavelength and a column interval of 1/2 or more of the signal wavelength. A shielding via conductor of
A waveguide portion surrounded by the two rows of shield via conductors and termination via conductors installed at two locations between the two rows of shield via conductors;
A second dielectric layer formed on the surface of the first conductor layer;
A first strip conductor formed on the surface of the second dielectric layer;
A third dielectric layer formed on the surface of the second conductor layer;
A second strip conductor formed on the surface of the third dielectric layer;
Located in the waveguide portion between the terminal via conductors installed at the two locations, through one opening formed in the first conductor layer, one end is connected to the first strip conductor, A first coupled via conductor having the other end connected to the waveguide portion;
Located in the waveguide portion between the terminal via conductors installed at the two locations, through one opening formed in the second conductor layer, one end is connected to the second strip conductor, A second coupled via conductor having the other end connected to the waveguide portion;
One of the first and second coupled via conductors is an input coupled via conductor and the other is an output coupled via conductor;
Two waveguide portions surrounded by the first coupling via conductor, the termination via conductor, the shielding via conductor, and the second coupling via conductor, the termination via conductor, and the shielding via conductor. The excited resonant mode produces an attenuation pole.

  In the high-frequency filter device according to the first aspect, the input coupling via conductor and the output coupling via conductor both penetrate the waveguide portion, and the other ends of the input coupling via conductor and the output coupling via conductor are respectively It is connected to the second conductor layer.

  In the high frequency filter device according to the second aspect, the first coupling via conductor penetrates the waveguide portion, and the other end of the first coupling via conductor is connected to the second conductor layer. And the second coupled via conductor passes through the waveguide portion, and the other end of the second coupled via conductor is connected to the first conductor layer.

  In the high-frequency filter device according to the first and second aspects, the shield via conductors are arranged on two parallel straight lines.

  Further, in the high-frequency filter device according to the first and second aspects, a row interval between two rows of shield via conductors forming a waveguide portion between a pair of coupled via conductors, the coupled via conductor and the termination The row spacing of the two rows of shield via conductors constituting the waveguide portion between the via conductors is different.

  According to the high frequency filter device of the present invention, the filter characteristics are determined by the relative positional relationship of the via conductors with respect to the conventional dielectric waveguide type filter device, so there is no influence of the overlay error of the substrate pattern. Yield improvement can be expected. In addition, since the attenuation pole can be easily introduced, it is possible to realize a steep filter characteristic and to remove a desired frequency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First embodiment.
First, a high frequency filter device according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a plan view showing the configuration of the high-frequency filter device of the present embodiment, FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1, and FIG. 3 is a perspective view thereof. FIG. 4 is a plan view showing in detail the positional relationship of each via conductor in the high frequency filter device of FIG.

As shown in FIGS. 1 to 3, in the high frequency filter device of this embodiment, a dielectric layer 1 and a dielectric layer 2 are laminated, and a conductor layer 4 and a conductor layer 5 are formed on both surfaces of the dielectric layer 1. It is the structure of the laminated substrate made. In addition, a plurality of via conductors are formed in the dielectric layer 1 so as to short-circuit the conductor layers 4 and 5, and each of these via conductors has a predetermined distance between adjacent via conductors. Each of the layers 1 is arranged so as to surround a predetermined region. By setting the distance between the via conductors to be ½ or less of the wavelength λ [mm] of the electromagnetic wave having a desired frequency in the medium of the dielectric layer 1, the via conductor functions as a shield via conductor. Here, when the speed of light in vacuum is c ₀ [mm / s], the signal frequency is f [1 / s], and the relative dielectric constant of the dielectric layer 1 is ε _r , the wavelength λ is λ = c ₀ / (f√ (ε _r )).

  The waveguide 12 is formed from the conductor layers 4 and 5, the via conductor that short-circuits the conductor layers 4 and 5, and the region in the dielectric layer 1 surrounded by the via conductor. The waveguide 12 has a width larger than λ / 2 in the dielectric layer 1 and extends over a predetermined length, and a propagation wave propagating in the waveguide 12 contributes to the filter operation. In the present specification and drawings, among the via conductors that short-circuit the conductor layers 4 and 5, the via conductors that are arranged on both sides of the waveguide 12 along the length direction of the waveguide 12 are referred to as shield via conductors 8. The one located at one end of the wave tube 12 is called a termination via conductor 9-1, and the one located at the other end of the waveguide 12 is called a termination via conductor 9-2.

  Furthermore, through holes 11-1 and 11-2 are formed at predetermined positions in the conductor layer 4 sandwiched between the dielectric layers 1 and 2 so as to be included in the waveguide 12. As an input / output port for signal input / output, at a first position in the waveguide 12 that is a predetermined distance from the end of the end of the waveguide 12 on the end via conductor 9-1 side, the dielectric layer 2 and the conductor A via conductor penetrating through hole 11-1 formed in layer 4 and dielectric layer 1 is provided as input / output coupling via conductor 10-1, and one end of input / output coupling via conductor 10-1 is a conductor. Connected to the layer 5, the other end is connected to one end of a strip conductor 6 formed on the surface of the dielectric layer 2. Similarly, as another input / output port for signal input / output, the waveguide 12 is located at a predetermined distance from the end of the waveguide 12 on the end via conductor 9-2 side and is different from the first position. In the second position, a via conductor penetrating the dielectric layer 2, the through hole 11-2 formed in the conductor layer 4, and the dielectric layer 1 is provided as an input / output coupling via conductor 10-2. The input / output coupling via conductor 10-2 has one end connected to the conductor layer 5 and the other end connected to one end of a strip conductor 7 formed on the surface of the dielectric layer 2. The strip conductors 6, 7, the dielectric layer 2, and the conductor layer 4 constitute a microstrip line signal line, respectively. The other ends of the strip conductors 6 and 7 are used as input / output ends 6a and 7a, respectively, for signal input and output to the high-frequency filter device.

If the arrangement interval of the shield via conductors 8 that determine the width of the waveguide 12 is appropriately selected based on the relative dielectric constant (ε _r ) of the dielectric layer 1 and the signal frequency to be used, the gap between the shield via conductors 8 is determined. This part functions as a waveguide, and a propagation mode can exist. The waveguide 12 is divided into three waveguide portions along the length direction of the waveguide 12 at the positions of the input / output coupling via conductors 10-1 and 10-2. The waveguide portion 12-1 between the input / output coupling via conductors 10-1 and 10-2, and the waveguide portion 12-2 between the termination via conductor 9-1 and the input / output coupling via conductor 10-1. , And a waveguide portion 12-3 between the termination via conductor 9-1 and the input / output coupling via conductor 10-2.

  Since the input / output coupling via conductors 10-1 and 10-2 are connected to the strip conductors 6 and 7 at one end and to the conductor layer 5 functioning as a ground conductor at the other end, one of the strip conductors (for example, When a signal is input from the strip conductor 6), a magnetic field is generated around the input / output coupling via conductor by a high-frequency current flowing in one input / output coupling via conductor (for example, the input / output coupling via conductor 10-1). The propagation mode is efficiently excited in the waveguide portion 12-1. Furthermore, this propagation mode couples with another input / output coupling via conductor (for example, input / output coupling via conductor 10-2), and generates an output signal at the input / output end of the corresponding strip conductor (for example, strip conductor 7). . Thus, a filter operation is realized by forming a pass band in the frequency band where the propagation mode exists and using the other frequency band as a stop band.

  In the configuration of the present embodiment, the input / output coupling via conductors 10-1 and 10-2 are grounded at one end to the conductor layer 5, so that the shield via conductor 8 and the termination via conductor 9-1 are coupled to the input / output. Waveguide portion 12-2 surrounded by via conductor 10-1 and / or waveguide surrounded by shield via conductor 8, termination via conductor 9-2 and input / output coupling via conductor 10-2. A resonance mode independent of other waveguide portions is excited in the portion 12-3. Further, since this resonance mode is separated from the other input / output coupling via conductor, as a one-port resonance circuit, a part of the input signal power is absorbed at the resonance frequency, and an attenuation pole is obtained at that frequency. It is done. Therefore, the influence on the band characteristics of the high-frequency filter device is minimized by adjusting the positional relationship of the via conductors so that the waveguide portion 12-2 or 12-3 has a resonance mode that resonates at a desired frequency. It is possible to effectively introduce an attenuation pole while suppressing it to the limit.

  In this embodiment, as shown in FIGS. 1 to 3, one end of the input / output coupling via conductors 10-1 and 10-2 is grounded to the conductor layer 5, but the present invention is not limited to this configuration. The input / output coupling via conductor may be configured to be electromagnetically coupled to the waveguide 12 and to be able to supply electromagnetic waves. Therefore, for example, the input / output coupling via conductor 10-1 may be formed from the strip conductor 6 toward the dielectric layer 1 in the waveguide 12 without contacting the conductor layers 4 and 5. The input / output coupling via conductor 10-2 may be formed from the strip conductor 7 toward the dielectric layer 1 in the waveguide 12 without contacting the conductor layers 4 and 5. In this case, compared to the case where one end of the input / output coupling via conductors 10-1 and 10-2 is grounded to the conductor layer 5, the shield via conductor 8, the termination via conductors 9-1 and 9-2, and the input / output coupling vias are provided. A coupling between the resonance mode of the waveguide portion 12-2 or 12-3 surrounded by the conductors 10-1 and 10-2 and the resonance mode of other waveguide portions is likely to occur. Depending on the band characteristics required, the ends of the input / output coupling via conductors 10-1 and 10-2 need not be grounded to the conductor layer 5.

  4 is a diagram illustrating the positional relationship between the shield via conductor 8, the termination via conductors 9-1 and 9-2, and the input / output coupling via conductors 10-1 and 10-2 in the high-frequency filter device of FIG. It is the top view which exposed the body layer 1 and the via conductors 8, 9-1, 9-2, 10-1, 10-2.

In FIG. 4, the shield via conductors 8 that respectively constitute the waveguide portions 12-1, 12-2, and 12-3 are shown as shield via conductors 8-1, 8-2, and 8-3. . D ₁ [mm] is the length of the waveguide portion 12-1 (that is, the distance between the input / output coupling via conductors 10-1 and 10-2), and D ₂ [mm] is the waveguide. The length of the tube portion 12-2 (that is, the distance between the termination via conductor 9-1 and the input / output coupling via conductor 10-1), and D ₃ [mm] is the length of the waveguide portion 12-3. (That is, the distance between the termination via conductor 9-2 and the input / output coupling via conductor 10-2). Further, W ₁ , W ₂ , W ₃ [mm] are the widths of the waveguide portions 12-1, 12-2, 12-3 (that is, the shield via conductors 8-1, 8-2, 8-3, respectively). The distance between the opposing parts of

The lowest order propagation mode in the waveguide 12 having the structure shown in FIGS. 1 to 3 is the TE ₀₁ propagation mode, which has a desired pass band as a high frequency filter device and is used for normal operation. It is essential that the TE ₀₁ propagation mode is not cut off in the waveguide portion 12-1 in the frequency range. Here, when the relative dielectric constant of the dielectric layer 1 to be used is ε _r , the desirable range of the width W ₁ of the waveguide portion 12-1 is as shown in the following equation.

[Equation 1]
λ / 2 <W ₁ <λ

  Furthermore, in the configuration of the present embodiment, the filter characteristics are substantially determined by the positional relationship between the via conductors in the dielectric layer 1 as shown in FIG. In the production of a general laminated dielectric substrate, the pattern accuracy within the dielectric layer is very high, but there is an alignment error between different dielectric layers or between the conductor pattern and the dielectric layer. For this reason, the accuracy of the pattern becomes very poor. Therefore, the high-frequency filter device having the configuration of the present embodiment has a serious problem in designing a multilayer dielectric substrate having a highly accurate structure, such as an overlay error between layers and a gap between a via conductor and a conductor pattern. The characteristics are hardly affected by the relative positional deviation, and it can be manufactured with very good reproducibility. Therefore, it is possible to expect a yield improvement when manufacturing a high-frequency filter device including a dielectric waveguide structure and a cost reduction of the manufacturing process.

  Hereinafter, with reference to FIG. 4, a method for determining the occurrence location of the attenuation pole in the high-frequency filter device of FIGS. 1 to 3 will be described.

  In FIG. 4, the shielding via conductors 8 are arranged in two rows of parallel straight lines, so that the waveguide portions 12-2 and 12-3 are arranged on the basis of the positions of the termination via conductors 9-1 and 9-2. The frequency of the resonant mode to be excited can be determined and an attenuation pole can be introduced.

The resonator length D [mm] (D indicates one of D ₂ and D ₃ ) in which the resonance mode exists in the waveguide portion 12-2 or 12-3 is the guide wavelength λ _g (in the waveguide). D = λ _g / 2 depending on the propagation mode wavelength). Here, the guide wavelength λ _g [mm] can be expressed by the following equation.

[Equation 2]
λ _g = 1 / (1 / λ ² −1 / λ _c ² ) ^1/2

Here, λ _c [mm] is a cutoff wavelength of the waveguide portion 12-2 or 12-3, and depends on the waveguide width W (W indicates either W ₂ or W ₃ ). λ _c = 2W. Therefore, in this case, the frequency of the attenuation pole can be determined by changing the resonator length D.

Furthermore, by making the widths W ₂ and W ₃ of the waveguide portions 12-2 and 12-3 different from the width W ₁ of the waveguide portion 12-1, it is more effective. An attenuation pole can be introduced. Here, as can be seen from the above formula, the in-tube wavelength λ _g changes greatly with a slight change in the waveguide width W when the signal wavelength λ is in the vicinity of the cutoff wavelength λ _{c of} the waveguide. If the width W ₂ or W ₃ is set to be cut off in the vicinity of the frequency of the desired attenuation pole, a slight change in the widths W ₂ and W ₃ causes the inside of the waveguide portions 12-2 and 12-3 to be in the tube. wavelength lambda _g is greatly changed, it is possible to change the resonance frequency in the waveguide section. Thereby, the frequency of the attenuation pole can be adjusted with good controllability and in a wide range. In this case, the frequency of the passband is determined by the characteristics of the propagation mode between the input / output coupling via conductors 10-1 and 10-2, which is mainly due to the width of the waveguide portion 12-1 (ie, the opposing shield via conductor 8). −1 distance) W ₁ and length (that is, the distance between the input / output coupling via conductors 10-1 and 10-2) D ₁ have a great influence on the waveguide portions 12-2 and 12-3. Even if the widths W ₂ and W ₃ are changed to adjust the frequency of the attenuation pole, there is an effect that the influence on the pass band is very small. However, if the frequency at which the desired attenuation pole is to be formed is cut off at the waveguide portion, the resonance mode is not excited and no attenuation pole can be formed, so the width W of the waveguide portions 12-2 and 12-3. A desirable range of ₂ and W ₃ is expressed by the following equation when the wavelength λ at the frequency of the desired attenuation pole is λ _n .

[Equation 3]
W ₂ > λ _n / 2.
[Equation 4]
W ₃ > λ _n / 2.

  Next, in order to better understand the present invention, specific examples of the above-described embodiment will be described.

First, the configuration of a high-frequency filter device in the 60 GHz band according to a specific example using the configuration of the present embodiment will be described. A ceramic material having a relative dielectric constant of 8 was used for the dielectric layer 1, and the conductive layers 4 and 5 were silver conductive films. The dielectric layer 1 has a thickness of 0.2 mm, and further, waveguide portions 12-1, 12-having a width W ₁ = W ₂ = W ₃ = 1 mm with a shield via conductor having a diameter of 0.1 mm at intervals of 0.5 mm. 2, 12-3 were arranged in two rows, and via conductors were also arranged on the outer side at a similar interval of 0.5 mm. Normally, a predetermined effect is exhibited by providing the shielding via conductors 8 in two rows as shown in FIGS. 1 to 3, but another inner layer high-frequency circuit is formed near the high-frequency filter device of this embodiment. This is because, in order to further enhance the shielding effect, it is effective to form an auxiliary shielding via conductor that short-circuits the conductor layers 4 and 5 in the same manner outside the shielding via conductor 8. In this case, it is effective if the auxiliary shielding via conductors are arranged at an interval of λ / 2 or less like the shielding via conductor 8. The lengths D ₂ and D ₃ of the waveguide portions 12-2 and 12-3 are both 1 mm. Further, a dielectric layer 2 having a thickness of 0.1 mm is formed of the same ceramic material, and strip conductors 6 and 7 constituting a microstrip line having a characteristic impedance of 50Ω are formed on the same by using silver as in the case of the conductor layers 4 and 5. It comprised with the electrically conductive film. The input / output coupling via conductors 10-1 and 10-2 are arranged symmetrically on the center line in the longitudinal direction of the waveguide portion 12-1 as shown in FIG. interval _{D 1} of the mutual of 10-2 was set to 1.5mm.

  FIG. 5 shows an example of frequency response characteristics calculated by electromagnetic field analysis. It can be seen that a good passband is realized in the vicinity of 60 GHz. The insertion loss in the band is expected to be 2 dB or less, and a very low loss characteristic is obtained. It can also be seen that the amount of attenuation suddenly increases because the lower frequency side of the pass band is the cutoff region of the waveguide 12. Therefore, it can be said that the characteristics of FIG. 5 are very suitable for filtering of leaky waves generated on the low frequency side of the desired frequency. A very clear attenuation pole is formed on the high frequency side of the pass band. This is because the waveguide portions 12-2 and 12-3 operate as resonators having the same frequency and form attenuation poles, and only one attenuation pole is observed.

As another embodiment, the case where the lengths D ₂ and D ₃ of the waveguide portions 12-2 and 12-3 are made different from each other as shown in FIG. 6 will be described. 6, by changing only the position of one end via conductors 9-1 and 0.9mm length _{D 2,} the length _{D 3} was left 1.0 mm. FIG. 7 shows the result of calculating the frequency response characteristics in this case by electromagnetic field analysis. It can be seen that the attenuation pole on the high frequency side is divided into two, thereby demonstrating that each resonance in the waveguide portions 12-2 and 12-3 forms an attenuation pole. Further, by providing a difference in the lengths D ₂ and D ₃ of the waveguide portions 12-2 and 12-3 in this way, an attenuation pole having a bandwidth can be formed as shown in FIG. More useful filter characteristics can be expected.

As another example, in FIG. 8, the positions of the termination via conductors 9-1 and 9-2 are not changed, and the lengths D ₂ = D ₃ = 1 mm of the waveguide portions 12-2 and 12-3. On the other hand, the case where the positions of the shield via conductors 8-2 and 8-3 are shifted and the widths W ₂ and W ₃ of the waveguide portions 12-2 and 12-3 are made different from each other will be described. In FIG. 8, W ₂ = 0.95 mm and W ₃ = 0.9 mm. FIG. 9 shows the result of calculating the frequency response characteristics in this case by electromagnetic field analysis. As in the case of FIG. 7, two attenuation poles are obtained, and it is understood that the frequency of the attenuation pole can be adjusted by changing the widths W ₂ and W ₃ of the waveguide portions 12-2 and 12-3. In this method, the lengths D ₂ and D ₃ of the waveguide portions 12-2 and 12-3 are kept constant, and the influence of the frequency change of the attenuation pole on the band characteristics is smaller. Further, by reducing the widths W ₂ and W ₃ of the waveguide portions 12-2 and 12-3 and bringing the cutoff frequencies of the waveguide portions 12-2 and 12-3 closer to the desired attenuation pole frequency. The in-tube wavelength is changed by a slight change in the widths W ₂ and W ₃ , the frequency of the attenuation pole can be greatly changed, the frequency adjustment range is widened, and the effectiveness is greater.

  In this specific embodiment, the ceramic layers have been described as examples of the dielectric layers 1 and 2, but the present invention is not limited to this. Any dielectric material can be used as the dielectric layers 1 and 2. Ceramic materials and resin materials are relatively suitable, but single crystal dielectric materials and semiconductor materials are also applicable.

  The usable frequency range of the high-frequency filter device of the present embodiment is not theoretically limited, but is substantially in the range of 10 GHz to 200 GHz when using a normal ceramic material or resin material and its manufacturing process. However, this is a desirable range in relation to the size and manufacturing accuracy of the high-frequency filter device.

Second embodiment.
First, a high frequency filter device according to a second embodiment of the present invention will be described with reference to FIGS. 10 is a plan view showing the configuration of the high-frequency filter device of this embodiment, FIG. 11 is a cross-sectional view taken along the line AA ′ of FIG. 10, and FIG. 12 is a perspective view thereof. The positional relationship among the shield via conductor 8, the termination via conductors 9-1 and 9-2, and the input / output coupling via conductors 10-1 and 10-2 is the same as that in the first embodiment shown in FIG. It is.

  As shown in FIGS. 10 to 12, the high frequency filter device of the present embodiment includes a dielectric layer 1, a dielectric layer 2, and a dielectric layer 3, and conductor layers 4 on both sides of the dielectric layer 1. It has a configuration of a laminated substrate on which the conductor layer 5 is formed. In addition, a plurality of via conductors are formed in the dielectric layer 1 so as to short-circuit the conductor layers 4 and 5, and each of these via conductors has a predetermined distance between adjacent via conductors. Each of the layers 1 is arranged so as to surround a predetermined region. By setting the distance between the via conductors to be ½ or less of the wavelength λ [mm] of the electromagnetic wave having a desired frequency in the medium of the dielectric layer 1, the via conductor functions as a shield via conductor.

  The waveguide 12 is formed from the conductor layers 4 and 5, the via conductor that short-circuits the conductor layers 4 and 5, and the region in the dielectric layer 1 surrounded by the via conductor. The waveguide 12 has a width larger than λ / 2 in the dielectric layer 1 and extends over a predetermined length, and a propagation wave propagating in the waveguide 12 contributes to the filter operation. In the present specification and drawings, among the via conductors that short-circuit the conductor layers 4 and 5, the via conductors that are arranged on both sides of the waveguide 12 along the length direction of the waveguide 12 are referred to as shield via conductors 8. The one located at one end of the wave tube 12 is called a termination via conductor 9-1, and the one located at the other end of the waveguide 12 is called a termination via conductor 9-2.

  Furthermore, a through hole 11-1 is formed at a predetermined position in the conductor layer 4 sandwiched between the dielectric layers 1 and 2 so as to be included in the waveguide 12, and sandwiched between the dielectric layers 1 and 3. The conductor layer 5 is formed with a through hole 11-2 at a predetermined position so as to be included in the waveguide 12. As an input / output port for signal input / output, at a first position in the waveguide 12 that is a predetermined distance from the end of the end of the waveguide 12 on the end via conductor 9-1 side, the dielectric layer 2 and the conductor A via conductor penetrating through hole 11-1 formed in layer 4 and dielectric layer 1 is provided as input / output coupling via conductor 10-1, and one end of input / output coupling via conductor 10-1 is a conductor. Connected to the layer 5, the other end is connected to one end of a strip conductor 6 formed on the surface of the dielectric layer 2. The strip conductor 6, the dielectric layer 2, and the conductor layer 4 constitute a signal line of a microstrip line. Similarly, as another input / output port for signal input / output, the waveguide 12 is located at a predetermined distance from the end of the waveguide 12 on the end via conductor 9-2 side and is different from the first position. In the second position, a via conductor penetrating the dielectric layer 3, the through hole 11-2 formed in the conductor layer 5, and the dielectric layer 1 is provided as an input / output coupling via conductor 10-2. One end of the input / output coupling via conductor 10-2 is connected to the conductor layer 4, and the other end is connected to one end of the strip conductor 7 formed on the surface of the dielectric layer 3. The strip conductor 7, the dielectric layer 3, and the conductor layer 5 constitute a signal line of a microstrip line. The other ends of the strip conductors 6 and 7 are used as input / output ends 6a and 7a, respectively, for signal input and output to the high-frequency filter device.

The arrangement interval of the shield via conductors 8 to determine the width of the waveguide 12, the dielectric constant of the dielectric layer 1 (epsilon _r) and the original to appropriately choose the signal frequency used during the shielding via conductors 8 This part functions as a waveguide, and a propagation mode can exist. The waveguide 12 has three waveguide portions 12-1, 12-2, 12-3 along the length direction of the waveguide 12 at the positions of the input / output coupling via conductors 10-1, 10-2. It is divided into.

  Since the input / output coupling via conductor 10-1 is connected to the strip conductor 6 at one end and to the conductor layer 5 functioning as a ground conductor at the other end, the input / output when a signal is input from the strip conductor 6 is input / output. A high frequency current flowing through the coupling via conductor 10-1 generates a magnetic field around the input / output coupling via conductor 10-1, thereby efficiently exciting a propagation mode within the waveguide portion 12-1. Furthermore, since the input / output coupling via conductor 10-2 is connected to the strip conductor 7 at one end and to the conductor layer 4 functioning as a ground conductor at the other end, it is excited by the input / output coupling via conductor 10-1. The transmitted propagation mode is coupled to the input / output coupling via conductor 10-2 and generates an output signal at the input / output end 7a of the strip conductor 7. Thus, a filter operation is realized by forming a pass band in the frequency band where the propagation mode exists and using the other frequency band as a stop band.

  Further, in the configuration of the present embodiment, one end of the input / output coupling via conductor 10-1 is grounded to the conductor layer 5, and one end of the input / output coupling via conductor 10-2 is grounded to the conductor layer 4, The waveguide portion 12-2 surrounded by the shield via conductor 8, the termination via conductor 9-1 and the input / output coupling via conductor 10-1, and / or the shield via conductor 8 and the termination via conductor 9-2 are inserted. In the waveguide portion 12-3 surrounded by the output coupling via conductor 10-2, a resonance mode independent from other waveguide portions is excited. Further, since this resonance mode is separated from the other input / output coupling via conductor, as a one-port resonance circuit, a part of the input signal power is absorbed at the resonance frequency, and an attenuation pole is obtained at that frequency. It is done. Therefore, the influence on the band characteristics of the high-frequency filter device is minimized by adjusting the positional relationship of the via conductors so that the waveguide portion 12-2 or 12-3 has a resonance mode that resonates at a desired frequency. It is possible to effectively introduce an attenuation pole while suppressing it to the limit.

  In this embodiment, as shown in FIGS. 10 to 12, one end of the input / output coupling via conductor 10-1 is grounded to the conductor layer 5, and one end of the input / output coupling via conductor 10-2 is grounded to the conductor layer 4. However, it is not limited to this configuration. The input / output coupling via conductor may be configured to be electromagnetically coupled to the waveguide 12 and to be able to supply electromagnetic waves. Therefore, for example, the input / output coupling via conductor 10-1 may be formed from the strip conductor 6 toward the dielectric layer 1 in the waveguide 12 without contacting the conductor layers 4 and 5. The input / output coupling via conductor 10-2 may be formed from the strip conductor 7 toward the dielectric layer 1 in the waveguide 12 without contacting the conductor layers 4 and 5. In this case, compared to the case where one end of the input / output coupling via conductors 10-1 and 10-2 is grounded to the conductor layer, the shielding via conductor 8, the termination via conductors 9-1 and 9-2, and the input / output coupling via conductors. The resonance mode of the waveguide portion 12-2 or 12-3 surrounded by 10-1 and 10-2 and the resonance mode of other waveguide portions are likely to be coupled, but the high frequency filter device Depending on the required band characteristics, it is not necessary to ground one end of the input / output coupling via conductors 10-1 and 10-2 to the conductor layer.

  Also in the configuration of the present embodiment, the configuration of the modification of the first embodiment described with reference to FIGS. 6 and 8 and the like can be applied. That is, as in the case of the first embodiment, there is an effect that the attenuation pole can be effectively introduced by the arrangement of the via conductors of the waveguide portions 12-2 and 12-3. In the configuration of the second embodiment, the filter portion is formed inside the substrate, and the input / output ends 6a and 7a are exposed on both sides of the substrate, so that the area utilization efficiency of the substrate is improved for the configuration using both sides of the substrate. Is very effective.

  By using the configuration of the high frequency filter device of the present invention, the filter element has a structure using only the inner layer of the multilayer substrate. Therefore, by using the surface layer of the multilayer substrate for antenna and chip mounting, the substrate area can be reduced. Usage efficiency is dramatically improved. In addition, there is no loss associated with interstage coupling, so the loss is low. In addition, since the via conductors are used for input / output coupling, the filter characteristics are determined by the relative positional relationship between the via conductors. Therefore, the yield is not affected by the pattern shift caused by the lamination, which is always a problem in the multilayer substrate. It has the feature that high production is possible. In addition, since the attenuation pole can be introduced with good controllability with a simple configuration, it is an effective means for forming a stop band on the high frequency side, which is one of the problems in a filter device including a waveguide structure.

It is a top view which shows the structure of the high frequency filter apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing in the A-A 'line of FIG. It is a perspective view of the high frequency filter apparatus of FIG. It is a top view explaining the positional relationship with the shielding via conductor 8, the termination | terminus via conductors 9-1 and 9-2, and the input-output coupling via conductors 10-1 and 10-2 in the high frequency filter apparatus of FIG. It is a graph which shows the frequency characteristic calculated by electromagnetic field analysis about the high frequency filter apparatus of FIG. The high frequency filter apparatus of the 1st Example which concerns on the 1st Embodiment of this invention is shown, The shielding via conductor 8, the termination | terminus via conductors 9-1 and 9-2, and the input-output coupling via conductor 10- in the said high frequency filter apparatus are shown. It is a top view explaining the positional relationship with 1 and 10-2. It is a graph which shows the frequency characteristic computed by the electromagnetic field analysis about the high frequency filter apparatus of FIG. The high frequency filter apparatus of the 2nd Example which concerns on the 1st Embodiment of this invention is shown, The shielding via conductor 8, the termination | terminus via conductors 9-1 and 9-2, and the input-output coupling via conductor 10- in the said high frequency filter apparatus are shown. It is a top view explaining the positional relationship with 1 and 10-2. It is a graph which shows the frequency characteristic calculated by the electromagnetic field analysis about the high frequency filter apparatus of FIG. It is a top view which shows the structure of the high frequency filter apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing in the A-A 'line of FIG. It is a perspective view of the high frequency filter apparatus of FIG.

Explanation of symbols

1, 2, 3 ... dielectric layer,
4, 5 ... conductor layer,
6, 7 ... Strip conductor,
6a, 7a ... input / output ends,
8, 8-1, 8-2, 8-3 ... shield via conductor,
9-1, 9-2 ... Termination via conductor,
10-1, 10-2 ... Input / output coupling via conductors,
11-1, 11-2 ... through holes,
12 ... Waveguide,
12-1, 12-2, 12-3 ... Waveguide portion.

Claims (6)

A high-frequency filter device in which at least one resonator is formed in a waveguide structure configured by laminating a plurality of dielectric layers,
A first dielectric layer and a pair of opposing first and second conductor layers formed on both sides of the dielectric layer;
A plurality of the first and second conductor layers are formed so as to be short-circuited, and are arranged in two rows with a mutual interval of 1/2 or less of the signal wavelength and a column interval of 1/2 or more of the signal wavelength. A shielding via conductor of
A waveguide portion surrounded by the two rows of shield via conductors and termination via conductors installed at two locations between the two rows of shield via conductors;
A second dielectric layer formed on the surface of the first conductor layer;
A pair of strip conductors formed on the surface of the second dielectric layer;
Located in the waveguide portion between the terminal via conductors installed at the two locations, through the opening formed in the first conductor layer, one end is respectively connected to the pair of strip conductors, An input coupling via conductor and an output coupling via conductor, the other end of which is connected to the waveguide portion, and
Resonance excited by two waveguide portions surrounded by the input coupling via conductor, the termination via conductor, the shielding via conductor, and the output coupling via conductor, the termination via conductor, and the shielding via conductor. A high frequency filter device characterized in that the mode generates an attenuation pole. A high-frequency filter device in which at least one resonator is formed in a waveguide structure configured by laminating a plurality of dielectric layers,
A first dielectric layer and a pair of opposing first and second conductor layers formed on both sides of the first dielectric layer;
A plurality of the first and second conductor layers are formed so as to be short-circuited, and are arranged in two rows with a mutual interval of 1/2 or less of the signal wavelength and a column interval of 1/2 or more of the signal wavelength. A shielding via conductor of
A waveguide portion surrounded by the two rows of shield via conductors and termination via conductors installed at two locations between the two rows of shield via conductors;
A second dielectric layer formed on the surface of the first conductor layer;
A first strip conductor formed on the surface of the second dielectric layer;
A third dielectric layer formed on the surface of the second conductor layer;
A second strip conductor formed on the surface of the third dielectric layer;
Located in the waveguide portion between the terminal via conductors installed at the two locations, through one opening formed in the first conductor layer, one end is connected to the first strip conductor, A first coupled via conductor having the other end connected to the waveguide portion;
Located in the waveguide portion between the terminal via conductors installed at the two locations, through one opening formed in the second conductor layer, one end is connected to the second strip conductor, A second coupled via conductor having the other end connected to the waveguide portion;
One of the first and second coupled via conductors is an input coupled via conductor and the other is an output coupled via conductor;
Two waveguide portions surrounded by the first coupling via conductor, the termination via conductor, the shielding via conductor, and the second coupling via conductor, the termination via conductor, and the shielding via conductor. A high-frequency filter device characterized in that an excited resonance mode generates an attenuation pole.   The input coupling via conductor and the output coupling via conductor both penetrate the waveguide portion, and the other ends of the input coupling via conductor and the output coupling via conductor are connected to the second conductor layer, respectively. The high-frequency filter device according to claim 1.   The first coupled via conductor passes through the waveguide portion, the other end of the first coupled via conductor is connected to the second conductor layer, and the second coupled via conductor is 3. The high frequency filter device according to claim 2, wherein the other end of the second coupling via conductor is connected to the first conductor layer through the waveguide portion.   3. The high frequency filter device according to claim 1, wherein the shielding via conductors are arranged on two lines of parallel straight lines.   Row spacing of two rows of shield via conductors forming a waveguide portion between a pair of coupled via conductors, and two rows of shields constituting a waveguide portion between the coupled via conductor and the termination via conductor 3. The high-frequency filter device according to claim 1, wherein the via conductor row spacing is different.

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