JP2024032075A - Waveguide filters, transmitters, and radars - Google Patents

Abstract

The present invention provides a waveguide filter that can improve power durability. [Solution] A waveguide filter includes at least one waveguide resonator that resonates radio waves in TE mode, and the waveguide resonator includes a waveguide line for input or output. A bonding window to be connected is formed, and the bonding window extends in the longitudinal direction, and among two long sides facing each other in the transverse direction, the center part of at least one long side is further away from the other long side than both sides. It has a shape. [Selection diagram] Figure 2

Description

The present invention relates to waveguide filters, transmitters, and radars.

As a technique for improving the power resistance performance of a waveguide filter, Patent Document 1 discloses a technique for hermetically sealing the inside of a waveguide to create a vacuum state. Furthermore, Patent Document 2 discloses a technique in which a stub is provided at a location where an electric field is concentrated.

Japanese Patent Application Publication No. 11-195903 Japanese Patent Application Publication No. 2006-157792

In recent years, in the field of marine radar, radio regulations have become stricter from the perspective of effective use of radio wave resources. Narrowing the bandwidth is considered to improve the performance of filters, and in waveguide filters it is necessary to narrow the coupling window. However, when the coupling window is narrowed, the distance between the electrodes becomes short, resulting in a problem that the power resistance performance deteriorates.

The present invention has been made in view of the above-mentioned problems, and its main purpose is to provide a waveguide filter capable of improving power resistance performance, and a transmitter and radar equipped with the same. .

In order to solve the above problems, a waveguide filter according to one aspect of the present invention includes at least one waveguide resonator that resonates radio waves in a TE mode, and the waveguide resonator has an input A coupling window is formed to which a waveguide type line for use or output is connected, and the coupling window extends in the longitudinal direction and extends in the center of at least one of the two long sides facing each other in the transverse direction. has a shape that is further away from the other long side than both sides. According to this, it becomes possible to improve the power durability performance.

In the above aspect, the coupling window may be formed at a position away from the center of the E-plane of the waveguide resonator. According to this, by forming the coupling window at a position away from the center of the E-plane where the electric field is concentrated, it is possible to improve the power resistance performance.

In the above aspect, the bonding window may have a shape in which, of the two long sides, a center portion of the long side closer to the center of the E-plane projects toward the center of the E-plane. According to this, by making the shape projecting toward the center of the E-plane where the electric field is concentrated, it is possible to improve the power durability.

In the above aspect, the coupling window may be formed in a range from an end of the E-plane of the waveguide resonator in a direction along one side to one-third of the length of the one side. According to this, by forming the coupling window at a position away from the center of the E-plane where the electric field is concentrated, it is possible to improve the power resistance performance.

In the above aspect, the direction of the electric field in the waveguide resonator may be different from the direction of the electric field in the waveguide line. Although the direction of the electric field is different, the electric field is disturbed in the vicinity of the coupling window, and discharge is likely to occur. However, by using the coupling window of the above embodiment, it is possible to improve the power resistance performance.

In the above aspect, the maximum width of the coupling window in the lateral direction may be greater than the depth of the H-plane of the waveguide resonator. According to this, the direction of the electric field changes easily in the vicinity of the coupling window, so it is possible to improve the power durability.

In the above aspect, the coupling window may be formed in a T-shape or a +-shape. According to this, the T-shape or the +-shape makes it possible to improve the power resistance performance.

In the above aspect, the combination window may be formed in a straight line from the center portion to the both side portions. According to this, it is possible to eliminate corners where electric fields tend to concentrate, and to further improve power durability performance.

In the above aspect, the bonding window may be formed in a triangular or rhombic shape. According to this, the triangular or rhombic shape makes it possible to improve the power resistance performance.

Further, a transmitter according to another aspect of the present invention includes the above-mentioned waveguide filter. According to this, it becomes possible to provide a waveguide filter that achieves improved power resistance performance.

Further, a radar according to another aspect of the present invention includes the above-mentioned waveguide filter. According to this, it becomes possible to provide a waveguide filter that achieves improved power resistance performance.

FIG. 2 is a diagram showing an example of the configuration of a radar. It is a figure showing an example of composition of a waveguide filter. It is a figure showing an example of composition of a waveguide filter. It is a figure showing an example of composition of a waveguide filter. It is a figure showing an example of composition of a waveguide filter. It is a figure showing an example of composition of a waveguide filter. It is a figure showing an example of composition of a waveguide filter. It is a figure showing an example of composition of a waveguide filter. FIG. 2 is a diagram showing a conventional example of a combining window. It is a figure showing the example of composition of a combination window. It is a figure showing the example of composition of a combination window. It is a figure showing the example of composition of a combination window. It is a figure showing the example of composition of a combination window. It is a figure showing the example of composition of a combination window.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration example of a radar 100 according to an embodiment. Radar 100 is a microwave transceiver that transmits and receives microwaves. The radar 100 is an example of a transmitter according to the embodiment, and includes the waveguide filter 1 according to the embodiment.

In addition to the waveguide filter 1, the radar 100 includes a magnetron 91, a pulse drive circuit 92, a circulator 93, a terminator 94, a circulator 95, a rotary joint 96, an antenna 97, a limiter circuit 98, and a receiving circuit 99.

The magnetron 91 is a microwave generator that oscillates, for example, a 9.4 GHz microwave as a fundamental wave. The pulse drive circuit 92 drives the magnetron 91 intermittently at a predetermined period to generate a pulsed transmission signal. The circulator 93 switches the output destination of the pulsed transmission signal from the magnetron 91.

Waveguide filter 1 is interposed between magnetron 91 and antenna 97. In this embodiment, the waveguide filter 1 is configured as a bandpass filter, allowing passage of a fundamental wave and suppressing passage of harmonics with respect to the fundamental wave. The suppressed harmonics are consumed in a terminator 94 connected to a circulator 93.

Circulator 95 outputs the transmitted signal from waveguide filter 1 to antenna 97 and outputs the received signal from antenna 97 to receiving circuit 99. The rotary joint 96 is interposed between the antenna 97 and the circulator 95, and electrically connects the rotating system and the stationary system.

The antenna 97, while being rotated by a motor (not shown), transmits a transmission signal as a radio wave pulse and converts a received reflected wave into a reception signal. The limiter circuit 98 suppresses a high level received signal immediately after the start of reception. Receiving circuit 99 acquires a received signal from antenna 97.

The path from the magnetron 91 to the antenna 97 is composed of a waveguide. Further, the path from the antenna 97 to the limiter circuit 98 is also formed of a waveguide.

In this embodiment, the radar 100 to which the waveguide filter 1 is applied is a marine radar that transmits and receives microwaves, but is not limited to this, but is, for example, a vehicle-mounted radar that transmits and receives millimeter waves for obstacle detection or collision prevention. It may also be a radar or the like.

FIG. 2 is an exploded perspective view showing a configuration example of the waveguide filter 1. As shown in FIG. The waveguide filter 1 includes two blocks 2 and 3 and a partition plate 4 sandwiched between them.

FIG. 3 is a diagram showing an example of the configuration of the block 2, and is a diagram of the block 2 viewed from the partition plate 4 side. FIG. 4 is a diagram showing an example of the configuration of the block 3, and is a diagram of the block 3 viewed from the partition plate 4 side.

FIG. 5 is a diagram showing an example of the configuration of the partition plate 4, and is a diagram of the partition plate 4 viewed from the block 3 side. FIG. 6 is a diagram showing a cross section of the block 2 taken along the line VI-VI shown in FIG.

The Z direction in the figure represents the thickness direction or stacking direction of the blocks 2 and 3 and the partition plate 4. The X direction and the Y direction represent the lateral direction and longitudinal direction of the blocks 2 and 3 and the partition plate 4, respectively, in a plane orthogonal to the Z direction.

The blocks 2 and 3 and the partition plate 4 are made of metal. Specifically, the blocks 2 and 3 are made of a conductive metal material such as aluminum. The partition plate 4 is also made of a conductive metal material such as an aluminum alloy.

The blocks 2 and 3 sandwich the partition plate 4, with the opposing surface 29 of the block 2 in contact with one main surface of the partition plate 4, and the opposing surface 39 of the block 3 in contact with the other main surface of the partition plate 4. The blocks 2 and 3 and the partition plate 4 are fastened together by fastening members such as screws (not shown).

As shown in FIG. 3, a recess 20 for radio wave propagation is formed in the opposing surface 29 of the block 2. The recess 20 includes two resonance regions 21 and 22 arranged in the Y direction and a coupling window 23 interposed between them. The resonance region 22 has additional regions 221 and 222 for adjusting harmonics.

A coupling window 25 is formed at the bottom of the resonant region 21 of the block 2 to communicate the resonant region 21 with the outside. An input waveguide line 82 (see FIG. 2) is connected to the coupling window 25, and radio waves are input from the waveguide line 82 to the resonance region 21 through the coupling window 25.

As shown in FIG. 4, a recess 30 for radio wave propagation is formed in the opposing surface 39 of the block 3. The recess 30 includes two resonance regions 31 and 32 arranged in the Y direction and a coupling window 33 interposed between them. The resonance region 31 has additional regions 311 and 312 for adjusting harmonics.

A coupling window 35 is formed at the bottom of the resonant region 32 of the block 3 to communicate the resonant region 32 with the outside. An output waveguide line 83 (see FIG. 2) is connected to the coupling window 35, and radio waves are output from the resonance region 32 to the waveguide line 83 through the coupling window 35.

As shown in FIG. 5, a plurality of coupling windows 41-45 are formed in the partition plate 4. The partition plate 4 is sandwiched between the blocks 2 and 3 and is interposed between the recesses 20 and 30. That is, the partition plate 4 covers both the recess 20 and the recess 30. In this embodiment, the recesses 20 and 30 have a mirror-symmetrical relationship.

The coupling windows 41-44 communicate the resonant region 22 of block 2 and the resonant region 31 of block 3. The coupling window 45 allows the resonance region 21 of the block 2 and the resonance region 32 of the block 3 to communicate with each other.

By assembling and fastening the blocks 2, 3 and the partition plate 4, each resonance region 21, 22, 31, 32 functions as a waveguide type resonator. In this embodiment, the waveguide filter 1 includes a total of four waveguide resonators. Each resonance region 21, 22, 31, 32 has a predetermined dimension determined based on the frequency of the radio wave (electromagnetic wave) used.

Radio waves from the input waveguide line 82 propagate to the resonance region 21 through the coupling window 25, propagate from the resonance region 21 to the resonance region 22 through the coupling window 23, and from the resonance region 22 through the coupling windows 41-44. It propagates to the resonant region 31 , from the resonant region 31 to the resonant region 32 through the coupling window 33 , and is finally outputted from the resonant region 32 through the coupling window 35 to the output waveguide line 83 . Further, some of the radio waves also propagate from the resonance region 21 to the resonance region 32 through the coupling window 45 .

Each of the resonance regions 21, 22, 31, and 32 has a flat shape in which the dimension in the Z direction is shorter than the dimension in the X direction and the Y direction, and causes received radio waves to resonate in the TE mode. The electric field vector of the resonant radio waves points in the Z direction. Note that each resonance region 21, 22, 31, 32 propagates a single mode radio wave.

FIGS. 7 and 8 are enlarged schematic diagrams focusing on the resonance region 21 that becomes the first-stage waveguide resonator and the coupling window 25 that becomes the entrance of radio waves. Note that the following explanation applies similarly to the resonant region 32 serving as the final stage waveguide resonator and the coupling window 35 serving as the exit of the radio wave.

The resonance region 21 has an E plane 211 and an H plane 212. The E-plane 211 is a plane orthogonal to the electric field vector (Z direction) of the radio waves resonating in the resonance region 21, and the H-plane 212 is a plane orthogonal to the E-plane 211.

As shown in FIG. 7, in this embodiment, the coupling window 25 is formed at a position away from the center C of the E plane 211 of the resonance region 21. In other words, the center C of the E plane 211 does not exist inside the coupling window 25.

The coupling window 25 is formed in a range from the end of the E plane 211 of the resonance region 21 in the direction along the long side (X direction) to one-third, preferably one-fourth, of the length Lx of the long side. be done. Note that it may be formed in a range up to one-third of the length of the short side from the end in the direction along the short side (Y direction).

When the coupling window 25 is formed on the E-plane 211, as shown in FIG. 8, the direction of the electric field in the waveguide type line 82 and the direction of the electric field in the resonance region 21 are different from each other. That is, the direction of the electric field in the waveguide line 82 and the direction of the electric field in the resonance region 21 are approximately orthogonal. While the direction of the electric field in the waveguide line 82 is in the X direction, the direction of the electric field changes when passing through the coupling window 25, and in the resonance region 21, the direction of the electric field becomes the Z direction.

Here, before explaining the details of the coupling window 25 of this embodiment, a conventional coupling window 75 shown in FIG. 9 will be explained.

The conventional coupling window 75 has a generally rectangular shape and has two long sides 76 and two short sides 78. In the illustrated example, the conventional coupling window 75 is a rounded rectangle with semicircular longitudinal ends. In such an elongated conventional coupling window 75, the electric field tends to concentrate at the center in the longitudinal direction, and discharge tends to occur.

In particular, when a coupling window is formed on the E-plane, the coupling window is closer to the center of the E-plane where the electric field strength is higher than when forming a coupling window on the H-plane, so that discharge is more likely to occur at the coupling window. Furthermore, since the direction of the electric field differs between the input line and the resonator, the electric field is likely to be disturbed near the coupling window, and discharge is likely to occur at the coupling window.

Therefore, in this embodiment, as described below, the long sides 26 and 27 of the joining window 25 are spaced apart from each other to form a T-shape, a +-shape, a triangular shape, or a rhombus shape. This alleviates the concentration of electric field in the center of the direction and improves power durability.

As shown in FIG. 7, the joining window 25 has a substantially rectangular shape, and has two long sides 26 and 27 that extend in the longitudinal direction and face each other in the transverse direction. It has two short sides 28 facing each other. In this embodiment, the longitudinal direction of the coupling window 25 is the Y direction, and the transversal direction is the X direction. Moreover, although the short side 28 is semicircular, it is not limited to this, and may be a straight line.

The joining window 25 has a shape in which, among the two long sides 26 and 27, the center portion 261 of one long side 26 is farther away from the other long side 27 than both side portions 262 are. The center portion 261 is a portion that includes the center of the long side 26, and is a portion that occupies, for example, one-fifth to one-half of the long side 26. The both side portions 262 are portions located on both sides of the center portion 261, and more specifically, are portions adjacent to the center portion 261 or portions of the long sides 26 excluding the center portion 261.

In the example shown in FIGS. 10 and 11, the coupling window 25 has a T-shape in which the center portion 261 of the long side 26 is further away from the other long side 27 than both side portions 262 are. Both sides 262 of the long side 26 are parallel to the other long side 27 , and a central portion 261 of the long side 26 projects in a direction away from the other long side 27 . The central portion 261 protrudes in an arcuate or semicircular shape.

In this example, of the two long sides 26 and 27, a center portion 261 of the long side 26 on the side closer to the center C of the E surface 221 protrudes toward the center C of the E surface 221. Thereby, concentration of the electric field can be alleviated on the long side 26 on the side closer to the center C of the E-plane 221 where the electric field strength is high, and it is possible to realize an improvement in power durability.

Further, the maximum width of the coupling window 25 in the lateral direction (X direction) is preferably larger than the depth Lz of the H-plane 212 of the resonance region 21 (see FIG. 8). The maximum width of the joining window 25 in the lateral direction is the distance from the apex of the center portion 261 of the long side 26 to the other long side 27.

As mentioned above, when the direction of the electric field in the waveguide type line 82 and the direction of the electric field in the resonance region 21 are approximately orthogonal, the electric field is likely to be disturbed near the coupling window 25, but in the lateral direction of the coupling window 25. By making the maximum width larger than the depth Lz of the H-plane 212, the electric field can easily escape from the coupling window 25 to the inside of the resonance region 21, and the power durability can be improved.

In the example shown in FIG. 12, the combined window 25 has a center portion 261 of the long side 26 farther from the long side 27 than both side portions 262, and a center portion 271 of the long side 27 is also further away from the long side 26 than both side portions 272. It has a + shape. That is, both sides 262 of the long side 26 and both sides 272 of the long side 27 are parallel, and the center part 261 of the long side 26 and the center part 271 of the long side 27 protrude in the direction away from each other. The central portions 261 and 271 protrude in an arcuate or semicircular shape.

Further, the maximum width of the joining window 25 in the transverse direction (X direction) is smaller than the maximum width of the joining window 25 in the longitudinal direction (Y direction), and in particular, it is half of the maximum width of the joining window 25 in the longitudinal direction. It is preferable that it is below. The maximum width of the joining window 25 in the lateral direction is the distance from the apex of the center portion 261 of the long side 26 to the apex of the center portion 271 of the long side 27 .

As shown in FIGS. 13 and 14, the combined window 25 has a shape in which the center portion 261 of the long sides 26 is further away from the other long side 27 than both side portions 262, and from the center portion 261 to both side portions 262. It may also be formed in a straight line. By forming a straight line from the center portion 261 to both side portions 262 in this manner, it is possible to eliminate corner portions and further alleviate concentration of the electric field.

In the example shown in FIG. 13, the joining window 25 has a substantially triangular shape in which the center portion 261 of the long side 26 is farther away from the other long side 27 than both side portions 262, and is linear from the center portion 261 to both side portions 262. have. The central portion 261 has an arc shape or a semicircular shape.

In the example shown in FIG. 14, in the joining window 25, the center part 261 of the long side 26 is further away from the long side 27 than the both sides 262, and is linear from the center part 261 to both sides 262; The center part 271 of 27 is further away from the long side 26 than both side parts 272, and has a substantially rhombic shape that is linear from the center part 271 to both side parts 272.

The central portions 261, 271 are arcuate or semicircular. Note that the coupling window 25 is not limited to a substantially rhombic shape, and may have a rectangular shape in which one of the central portions 261 and 271 protrudes more than the other, for example.

In the above explanation, the shape of the coupling window 25 formed in the resonant region 21 which becomes the first stage waveguide resonator was explained, but the shape of the coupling window 25 formed in the resonant region 32 which becomes the final stage waveguide resonator was explained. The combined window 35 also has the same shape. At least one of the coupling windows 25 and 35 may have the same shape.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and it goes without saying that various modifications can be made by those skilled in the art.

In the above embodiment, the waveguide type filter 1 includes a total of four waveguide type resonators (resonance regions 21, 22, 31, 32), but the number of resonators is not limited to this, for example, 1 to 1. It may be any one of 3 or 5 or more.

Further, in the above embodiment, the coupling window 25 is formed on the E plane 211 of the resonance region 21, but the coupling window 25 is not limited to this, and may be formed on the H plane 212 of the resonance region 21.

Further, in the above embodiments, the waveguide type resonator is a cavity resonator, but the inside does not need to be filled with air, and may be filled with, for example, a solid dielectric. Further, an electrode film may be formed on the outer surface of the dielectric block.

Hereinafter, typical embodiments of the present invention will be listed.

(1)
comprising at least one waveguide resonator that resonates radio waves in TE mode,
A coupling window is formed in the waveguide resonator to which a waveguide line for input or output is connected,
The bonding window extends in the longitudinal direction and has a shape in which the center part of at least one of the two long sides facing each other in the transverse direction is further away from the other long side than both sides.
waveguide filter.

(2)
The coupling window is formed at a position away from the center of the E-plane of the waveguide resonator.
The waveguide filter according to (1).

(3)
The bonding window has a shape in which, of the two long sides, the center of the long side closer to the center of the E surface protrudes toward the center of the E surface.
The waveguide filter according to (2).

(4)
The coupling window is formed in a range from an end in a direction along one side of the E-plane of the waveguide resonator to a quarter of the length of the one side.
The waveguide filter according to any one of (1) to (3).

(5)
The direction of the electric field in the waveguide resonator is different from the direction of the electric field in the waveguide line.
The waveguide filter according to any one of (1) to (4).

(6)
The maximum width of the coupling window in the lateral direction is greater than the depth of the H-plane of the waveguide resonator.
The waveguide filter according to any one of (1) to (5).

(7)
The coupling window is formed in a T-shape or a +-shape,
The waveguide filter according to any one of (1) to (6).

(8)
The combining window is formed in a straight line from the center part to the both sides,
The waveguide filter according to any one of (1) to (6).

(9)
The bonding window is formed in a triangular or rhombic shape.
The waveguide filter according to any one of (1) to (6) and (8).

(10)
A transmitter comprising the waveguide filter according to any one of (1) to (9).

(11)
A radar comprising the waveguide filter according to any one of (1) to (9).

1 waveguide filter, 2 block, 20 recess, 21, 22 resonance region, 211 E plane, 212 H plane, 221, 222 additional region, 23, 25 coupling window, 26, 27 long side, 261, 271 central part, 262, 272 both sides, 28 short side, 29 opposing surface, 3 block, 30 recess, 31, 32 resonance area, 311, 312 additional area, 33, 35 coupling window, 39 opposing surface, 4 partition plate, 41-45 coupling window, 82, 83 waveguide line, 91 magnetron, 92 pulse drive circuit, 93 circulator, 94 terminator, 95 circulator, 96 rotary joint, 97 antenna, 98 limiter circuit, 99 receiving circuit, 100 radar

Claims (11)

comprising at least one waveguide resonator that resonates radio waves in TE mode,
A coupling window is formed in the waveguide resonator to which a waveguide line for input or output is connected,
The bonding window extends in the longitudinal direction and has a shape in which the center part of at least one of the two long sides facing each other in the transverse direction is further away from the other long side than both sides.
waveguide filter. The coupling window is formed at a position away from the center of the E-plane of the waveguide resonator.
The waveguide filter according to claim 1. The bonding window has a shape in which, of the two long sides, the center of the long side closer to the center of the E surface protrudes toward the center of the E surface.
The waveguide filter according to claim 2. The coupling window is formed in a range from an end along one side of the E-plane of the waveguide resonator to one third of the length of the one side.
The waveguide filter according to claim 1. The direction of the electric field in the waveguide resonator is different from the direction of the electric field in the waveguide line.
The waveguide filter according to claim 2. The maximum width of the coupling window in the lateral direction is greater than the depth of the H-plane of the waveguide resonator.
The waveguide filter according to claim 2. The coupling window is formed in a T-shape or a +-shape,
The waveguide filter according to claim 1. The combining window is formed in a straight line from the center part to the both sides,
The waveguide filter according to claim 1. The bonding window is formed in a triangular or rhombic shape.
The waveguide filter according to claim 1. A transmitter comprising the waveguide filter according to claim 1. A radar comprising the waveguide filter according to claim 1.

Images