KR920002440B1 - Slot array antenna - Google Patents

Abstract

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Description

Slot array antenna

1 is a perspective view showing a slotted array antenna according to the present invention.

2A-2D show various arrangements of power radiating slots of an antenna.

3 is a graph showing the power density distribution in the space of an antenna.

4a and 4b are exemplary views showing the radial direction of the antenna.

5 is a perspective view showing a first modification of the antenna of FIG.

6 is a graph showing the power density distribution of the first modification.

7 is a perspective view showing a second modification.

8 is a perspective view showing a third modification.

9A and 9B are perspective views showing the trumpet waveguide of the antenna.

10 is a perspective view showing a second embodiment of the present invention.

11 is a perspective view showing a third embodiment.

12 is a perspective view showing a fourth embodiment.

13 is a plan view showing a fifth embodiment.

14A is a plan view showing a sixth embodiment.

14B is a plan view showing a seventh embodiment.

14C is a plan view showing an eighth embodiment.

Fig. 15A is a front view showing the power supply means for the fourth modification of the first embodiment.

FIG. 15B is a front view showing the power supply means for the fifth modification; FIG.

16A is a perspective view of a power supply means.

FIG. 16b is a perspective view of the antenna with the power supply means of FIG. 15a;

FIG. 16c shows a perspective view of the antenna with the power supply means of FIG. 15b.

17 is a perspective view showing a ninth embodiment of the present invention.

18A and 18B are exemplary views showing the directivity of the antenna of the ninth embodiment.

19 is a perspective view showing a tenth embodiment.

20 is a perspective view showing an eleventh embodiment.

21A is an exemplary diagram showing electric field distribution in an antenna.

21B is an illustration showing the form of a current.

22 is a perspective view of a conventional slotted array antenna.

* Explanation of symbols for main parts of the drawings

4: power supply opening 5: trumpet waveguide

G: rectangular waveguide 1, 2: rectangular metal plate

3: metal side plate S: rectangular waveguide space

W: width λg: wavelength

le: length d: height

1a: power radiation slot 7: terminal resistance

6: lens antenna

The present invention relates to a slotted array antenna for communication and broadcasting.

The slotted array antenna has a plurality of slots formed in the plate of the rectangular waveguide. FIG. 21A shows the electric field distribution in the rectangular waveguide and FIG. 21B shows the shape of the current. As with the propagation mode in the rectangular waveguide, the basic mode (TE ₁₀ or TE ₁ wave) with minimum attenuation in rectangular coordinates is used. If the cutoff frequency is fc, the luminous flux is c, and the length of the long side of the waveguide is a, the waveguide is used in a frequency range between fc = c / 2a and fc ₂₀ = c / a, where other higher order attenuation occurs. Therefore, the long side length a is when the free space wavelength is λ,

a = λ / 1.06 and a '= λ / 1.56, and the short side length b is about a / 2.

The slot of a conventional slotted array antenna is formed in the plate of the waveguide. As shown in FIG. 22, the direction of the current is reversed at every lambda g / 2 (lambda g is the wavelength in the waveguide). Thus, the tilt direction of the slots is opposite to the adjacent ones. Thus, all the Z components of the synthesized electric field of the wave radiated from each slot are located in one direction, and the Y components are reversed and canceled out. As a result, linear polarization radiates from the slot. The width of the x-y in-plane beam is narrow between 16 ° and 20 ° and the one in x-z plane narrows between 1 ° and 2 ° proportional to the number of slots.

Since the beam width in the horizontal plane is narrow and the beam width in the vertical plane is wide, the gain of the always slotted array antenna is small. Thus, although the present antenna is useful for radar systems, it is not suitable for use as an antenna for communication, broadcasting, and the like.

An object of the present invention is to provide a slotted array antenna which is useful as a communication and broadcasting antenna with a simple structure and light weight.

According to the present invention, there is provided a rectangular waveguide having a rectangular cross-sectional shape formed by a metal plate and having a space having a power supply opening, and a power supply means coupled to the rectangular waveguide at the power supply opening, the rectangular waveguide having the It has a plurality of wave-emitting slots formed in one of the metal plates forming the long sides of the rectangular cross-sectional shape.

The width of the rectangular waveguide is four or more times the size of the wavelength in the space, the height of the rectangular waveguide is one half or more of the wavelength, and the power supply means has means for supplying power to the space in the form of a plane wave.

In the present invention, the rectangular waveguide has a terminal resistor and slow-wave means in the end plate. The space is reduced towards the end plate. Moreover, the rectangular waveguide has a plurality of rectangular waveguides coupled to each other, and a matching member is provided for directing the electric power supplied from the power supply means to the longitudinal waveguide.

These and other objects and features of the present invention are described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 showing a first embodiment of the present invention, a slotted array antenna according to the present invention has a rectangular waveguide G having a power supply opening 4 formed at an inlet side thereof, and includes a bugle waveguide ( 5) is coupled to the rectangular waveguide G at the power supply opening 4. The rectangular waveguide G comprises a waveguide S having an opposing rectangular metal plate 1 and 2 and a metal side plate 3 fixed to three sides of each plate 1 (2) with a longitudinal cross-sectional equilibrium. Form. The width W of the rectangular waveguide is four times (4 lambda g) or more than the wavelength lambda g in the space S, and the length le is 4 lambda g or more. The height d is 1/2 (λg / 2) or more of the wavelength λg. The height d is 1/2 (λg / 2) or more of the wavelength λg. Width (W): Height (d) is 5: 1 or more. The metal plate 1 in the E plane has a plurality of power radiation slots 1a arranged in a matrix. The terminal resistor 7 is provided inside the end plate 3 of the rectangular waveguide G. As shown in FIG. The trumpet waveguide 5 has a trumpet shape in the E plane and has a lens antenna 6 therein. The lens antenna 6 is made of a dielectric or metal plate, or of a corrugated metal plate. In the trumpet waveguide 5, a partition 5a is disposed in the axial direction at the center to prevent phase disorder.

Electric power propagates in the trumpet waveguide 5, with the in-phase surface coaxial to the virtual origin. Electric power is converted into plane waves when passing through the lens antenna 6. Thus, electric power is supplied to the rectangular waveguide G in the form of plane waves whose electric fields are directed in the width direction. The equipotential power is radiated from the slot 1a. The remaining power in the rectangular waveguide G is absorbed in the terminal resistor 7, thereby preventing the influence of the reflected power. If the waveguide G is so well designed that the power supplied from the bugle waveguide 5 is prevented from the slot 1a, the terminal resistor 7 becomes unnecessary.

The slot may be formed in the H plane (x-z plane in Fig. 21a) perpendicular to the direction of the electric field. Since the current on the H plane is distributed sinusoidally, the slots are also sinusoidal. Such distribution results in irregular radiation of current and power, thereby reducing antenna efficiency.

In the slotted array antenna of the present invention, the slot is formed on the E plane parallel to the direction of the electric field in the waveguide G, where the current flows uniformly. Thus, the slots are arranged uniformly, thereby increasing the antenna efficiency.

2a to 2d show various arrangements of the slot 1a. Slots in FIG. 2A are arranged at a distance P1 of λg / 4 and a distance P2 of λg. The slot is perpendicular to the direction of the adjacent slot. The synthesized electric field of waves radiated from a pair of slots becomes a circularly olarized wave.

The other slotted array antennas shown in Figures 2b-2d emit linearly polarized waves. Since the ten slots are arranged horizontally and vertically, the gain rises and the directivity becomes sharp. For example, if the width W is 50 cm, the length le is 50 cm and the distance d is 2 cm, the gain is 35.5 dB at about 12 GHz.

In the arrangement of the slots described above, the beam is radiated in a direction perpendicular to the metal plate 1. If the distance between the slots 1a deviates from [lambda] g, the direction of the beam is tilted as described later with reference to FIGS. 4A and 4B.

3 shows the power density distribution in the space S of the waveguide G according to the first embodiment. The power density decreases towards the terminal resistor 7 due to power radiation from the slot 1a. Thus, the power distribution is irregular and the antenna gain is reduced.

The first modification shown in FIG. 5 is to radiate power evenly. The height d of the H plane is reduced toward the terminal resistance 7 in a straight line or curve. Thus, the power is distributed almost uniformly as shown in FIG. 6, thereby increasing the antenna gain.

However, for such an antenna, the height d should be d> λg / 2 so as not to block any frequency. Moreover, the wavelength lambda g in space also varies with the height d. (λg = λ / (1- (λ / 2d) ² ) where λ is the wavelength in free space) Therefore, it is necessary to design the distance between slots according to the change of the wavelength λg. Other operations and advantages other than the above description are the same as in the first embodiment.

7 shows a second variant of the present invention. A straight line or curve of the width W of the E plane decreases at the end, thereby providing a nearly uniform distribution of radiant power. Since the height d is constant, the wavelength lambda g does not change. In that way, the design of the antenna is easy since there is no need to change the slot distance.

Since the height d is not allowed to be greatly increased, the wavelength lambda g in the space S becomes larger than the wavelength lambda in the free space, and the slot distance becomes large. Other operations and advantages other than the above description are the same as in the first embodiment.

As a third variant, the antenna shown in FIG. 8 reduces the slot distance. In the space S, a slow wave device 8 such as a dielectric or corrugated metal plate is provided. In this figure, the space S is filled with polyethylene foam as the dielectric. The phase constant of the electric power propagated in the space S of the rectangular waveguide G is controlled by the slow wave device 8 to reduce the wavelength lambda g in the space S. Thus, it is possible to increase the density of the slots in order to increase the efficiency of the antenna. If the lambda g is approximately equal to the wavelength lambda, the grating lobe becomes large to reduce antenna efficiency. Therefore, it is necessary to design a phase constant so that wavelength (lambda) g and wavelength (lambda) do not become the same. Other operations and advantages other than the above description are the same as in the first embodiment.

9A shows a bugle waveguide 5 as the power supply means for the antenna described above. The opening angle θ of the bugle waveguide is smaller than 30 ° to provide the main mode wave. If the length L is shortened, the opening angle θ increases. When the opening angle θ exceeds 40 °, as shown in FIG. 9B, a higher order mode occurs to cause phase disorder.

The second embodiment shown in FIG. 10 has a bugle waveguide that prevents phase disorder. The trumpet waveguide is provided with a pair of parallel trumpet waveguides 5 'and a T-shaped branch feeder waveguide 5c. The other part of the antenna is the same as in the first embodiment in structure. Due to such a structure, the opening angle is reduced, and the power supplied to the bugle waveguide 5 'becomes almost a plane wave. Thus, the lens antenna 6 can be omitted, and the higher order mode can be prevented. If the lens antenna 6 is used for the bugle waveguide 5 'to make the equiphase plane flat, the length of the bugle waveguide 5' is further reduced. The first to third variants can be used for the trumpet waveguide of the second embodiment, and operation and advantages attributable to each variant are obtained.

The power supply stage guide 5b for the T-type supply waveguide 5c is provided at another position, for example, below it, or inside as shown by an upper surface or a dashed line. It is noted that the phase in the feeder waveguide 5c is reversed when power is supplied from the top or bottom of the waveguide 5c.

Referring to FIG. 11 showing the third embodiment of the present invention, the waveguide 10 having the supply opening 9a on its metal plate 9 is attached to the rectangular waveguide G as a power supply means. The other structure is the same as in the first embodiment. Electric power propagates from the opening portion 9a to the space S as plane waves.

The shape of the opening 9a is circular or rectangular. By varying the diameter of the circular opening, or by changing the length of the long and short sides of the rectangular opening, or by changing the inclination and position of the rectangular opening, the electric field and magnetic field in the space S of the rectangular waveguide The direction can be adjusted. Moreover, the distribution of radiant power becomes equal. Other operations and advantages other than the above description are the same as in the first embodiment. The first to third variants shown in Figs. 5, 7 and 8 are also applied to the power supply means with waveguides having openings, so that the operation and advantages resulting from the respective modifications are obtained.

12 shows a fourth embodiment of the present invention. The branch feeder waveguide 5c has a multistage type forming a multistage split waveguide. The other structure is the same as in the first embodiment. The first to third variants shown in FIGS. 5, 7 and 8 can also be applied to the antenna of this embodiment.

Referring to FIGS. 13 to 14C, in which the fifth to eighth embodiments of the present invention are shown, the antenna of the fifth embodiment has an offset reflector 12, and the antennas of the sixth and seventh embodiments each have a casegrain reflector ( 13) and a Gregorian reflector 14, the antenna of the eighth embodiment having a parabolic reflector 15. Power supply waveguide means are provided on each reflector. These embodiments have almost the same operation and advantages as the first embodiment. The first to third variants shown in Figs. 5, 7 and 8 are also applied to the antennas of the fifth to eighth embodiments, and the operation and advantages resulting from each variant are obtained.

15A and 15B respectively show power supply means for the fourth variant of the first embodiment and power supply means for the fifth variant. Each power supply means consists of a substrate 16b of a dielectric, a branch strip 16 close to one side of the substrate 16b, and a ground plate 17 (FIG. 16a) provided on the other side of the substrate. It is a strip line. The strip 16 has a feed end 16a. As shown in 16a, the ground plates 17 each have a plurality of radiating slots 17a opposite the feed end 16c of the strip 16. The reflecting plate 18 faces the ground plate 17 at intervals through spacers (not shown). The distance h between the reflecting substrate 18 and the ground plate 17 is approximately lambda / 4 so that power is radiated from the slot 17a in a predetermined direction. The distance L between the feeder ends 16c is λ / 2, and adjacent slots are inclined in opposite directions to each other. Thus, the synthesized electric field direction of the power radiated from the slot is shown by the arrow in FIG. 16A.

Figures 16b and 16c show an antenna with the power supply means shown in figures 15a or 15b. The feeder means is attached to the antenna such that the slot 17a opens into the power supply opening 4 of the rectangular waveguide G. The antenna of FIG. 16C has a pair of adjacent rectangular waveguides G. FIG. Thus, the power supply means constituting the pair of microstrip wires is attached to the center of the antenna. The first to third variants shown in FIGS. 5, 7 and 8 can also be applied to the antenna of this embodiment. Although the slot 17a is used as the radiating element in the above embodiment, other elements can be used.

Referring to FIG. 17, in which a ninth embodiment of the invention is shown, the antenna has a pair of adjacent rectangular waveguides G. As shown in FIG. Each rectangular waveguide G is provided with opposing rectangular metal plates 1 and 2 and metal plates 3 fixed to three sides of each plate to form a waveguide space S having a rectangular cross-sectional shape. The metal plate 1 in the E plane has a plurality of power radiation slots 1a, and the power supply opening 4 is formed at the inlet side of the space S. As shown in FIG. The two waveguides are coupled to each other, forming a space between them. The trumpet waveguide 5 is vertically coupled to the underside of the antenna in communication with the space between the power supply openings 4. The electric field of the waveguide is sufficiently increased compared to the wavelength in the space (S). The matching member 11 is provided in the space between the opening 4 as a reflector member. The trumpet waveguide 5 has a trumpet shape in the E plane and a lens antenna 6 therein. The lens antenna 6 is made of a dielectric or metal plate or corrugated metal plate. In the bugle waveguide 5, the intermediate partition 5a is arranged in the axial direction.

Referring to FIG. 4A in which the radial direction in the first embodiment is shown, if the wavelength λ1 of the electric power supplied to the space S of the rectangular waveguide is the set wavelength λ ₀ (distance between the slots 1a) If shorter than), the phase of power radiated from slot 1a-1 precedes the phase of power radiated from slot 1a-2 by the difference between λ ₀ and λ ₁ (λ ₀ -λ ₁ ). Therefore, mainly lobe P is inclined toward r as shown in FIG. 4B. When the wavelength lambda 1 is longer than the wavelength lambda 0, the mainly paw P is inclined toward ℓ.

18A and 18B show the directivity of the antenna of the ninth embodiment shown in FIG. The power supply from the power supply means 5 is divided by the matching member 11 with respect to the left and right spaces of the rectangular waveguide G. The divided power is propagated symmetrically into the left and right spaces (S). Therefore, if the wavelength of the power is changed, the left lobe P1 and the space lobe P2 are inclined symmetrically as shown in Fig. 18B. Thus, mainly the synthesis direction of the paw P is advantageously perpendicular to the surface of the antenna. The other structure is the same as in the first embodiment. The modified rectangular waveguides of the fifth, seventh and eighth degrees and other power supply means can optionally be used for the antenna of this embodiment.

Referring to FIG. 19, in which a tenth embodiment of the present invention is shown, the rectangular waveguide G includes a pair of adjacent rectangular waveguides and a pair of bugle waveguides 5 provided below the pair of rectangular waveguides. The rectangular waveguide G has a power supply opening 4 at both ends thereof and a terminal resistor 7 at its center. The trumpet waveguide 5 is provided parallel and symmetrically to the rectangular waveguide G and communicates with the power supply opening 4. In both ends of the rectangular waveguide G, the matching member 11 is provided as a reflector means for reflecting the electric power supplied to the space S. As shown in FIG. A lens antenna 6 of dielectric is provided in each bugle waveguide 5. Thus, almost the same operation and advantages are obtained with the first and ninth embodiments. Modified rectangular waveguides of 5, 7 and 8 degrees and other power supply means are optionally used for the antenna of this embodiment.

Referring to FIG. 20, in which an eleventh embodiment of the present invention is shown, the antenna has a pair of parallel rectangular waveguides G. As shown in FIG. Since the opening angle of each bugle waveguide 5 can be reduced, the electric power propagated in the waveguide becomes a substantially planar wave, and the higher order mode is prevented. The other structure is the same as that of the first embodiment. The modified rectangular waveguides of the fifth, seventh and eighth degrees and other power supply means can be selectively used for the antenna of this embodiment.

From the foregoing, it will be appreciated that the antenna of the present invention has the following advantages.

(1) Since the slot is formed in the E plane parallel to the direction of the electric field in the waveguide G, the current flows uniformly. Thus, the slots are uniformly arranged and the antenna efficiency is increased.

(2) The phase constant of the electric power propagated in the space of the rectangular waveguide can be controlled by the slow wave device to reduce the tube wavelength. Thus, it is possible to increase the density of the slot for increasing the efficiency of the antenna.

(3) Since the distance between the H planes is reduced toward the terminal resistance, the power is distributed almost uniformly.

Although the invention has been described in connection with specific preferred embodiments, this description is intended to illustrate and not limit the scope of the invention as defined by the following claims.

Claims (6)

A rectangular waveguide (G) having a rectangular cross-sectional shape formed by metal plates (1, 2, 3) and having a space (S) having a power supply opening (4), and at the power supply opening (4) the rectangular waveguide ( Power supply means (5, 5 'and 5', 5C, 10, 12, 13, 14, 15, 15a and 16a, 15b and 16a) coupled to G), and The rectangular waveguide (G) is a slot array antenna having a plurality of radiating slots (1a) formed in one of the metal plates forming the longitudinal sections of the rectangular cross-sectional shape, the width (W) of the rectangular waveguide is the space ( S) is four times or more than the wavelength length (λg), the height (d) of the rectangular waveguide is 1/2 or more of the wavelength, the power supply means in the form of a plane wave in the space (S) And a means for supplying power to the slotted array antenna. 2. Slotted antenna according to claim 1, characterized in that the rectangular waveguide (G) has a terminal resistor (7) at the end plate opposite the power supply opening (4). The slotted array antenna according to claim 1 or 2, wherein the rectangular waveguide (G) has a slow wave means (8). The slotted array antenna according to claim 1, wherein the space (S) is reduced toward the end plate (FIGS. 5, 7). 2. The slotted array antenna according to claim 1, wherein the rectangular waveguide comprises a plurality of rectangular waveguides (G and G) coupled to each other. 6. Slotted antenna according to claim 5, characterized by having a mating member (11) for directing the power supplied from said power supply means (5 and 5) to said rectangular waveguides (G and G).

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