JP2019122012A - Frequency selection board and electronic circuit - Google Patents

Abstract

To obtain a frequency selection board capable of suppressing high harmonic waves.SOLUTION: A plurality of lines 11 each configured by element conductor patterns 12 and a connection part 13 for connecting between a first element conductor pattern and a second element conductor pattern adjacent to each other, are arranged in parallel to each other. The connection part 13 comprises a diode that is an active element, and a high harmonic wave reduction part. The high harmonic wave reduction part is arranged at least one of between the diode and the first element conductor pattern and between the diode and the second element conductor pattern.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a frequency selective plate and an electronic circuit that reflect or transmit radio waves.

  BACKGROUND Conventionally, a frequency selective surface (FSS) is known as a device that reflects or transmits radio waves of a specific frequency.

  For example, Patent Document 1 discloses a frequency selection plate in which a plurality of element patterns are arranged and adjacent element patterns are connected by a diode.

JP 2005-236620 A

  Here, when radio waves are received by the frequency selection plate, an alternating high frequency signal flows to the diode. In addition, harmonics are generated when a high frequency signal is rectified by a diode and converted to a direct current signal. The generated harmonics are propagated to the element conductor pattern connected to the diode, and radiated from the element conductor pattern to the outside as an unnecessary wave.

  If this unnecessary wave is large, there is a possibility that the inspection at the time of product shipment may exceed the allowable value set by the law.

  This invention is made in view of the above, Comprising: It aims at providing the frequency selection board which can suppress a harmonic, and an electronic circuit.

  In order to solve the problems described above and to achieve the object, the present invention is configured by an element conductor pattern and a connection portion that connects an adjacent first element conductor pattern and a second element conductor pattern. A plurality of lines are arranged in parallel, and the connection portion is provided on at least one of the active element, the active element and the first element conductor pattern, and between the active element and the second element conductor pattern And a harmonic reduction unit disposed.

  According to the present invention, it is possible to suppress harmonics.

The figure which shows the structure of the frequency selection board in Embodiment 1. A diagram showing a configuration of a connection unit in the first embodiment The figure which shows the structure of the modification of the connection part in Embodiment 1. The figure which shows the structure at the time of arrange | positioning the frequency selection board in Embodiment 1 in a radome. A diagram provided for describing the operation of the frequency selection plate when radio waves are emitted from the radar antenna unit according to the first embodiment. The figure which shows the structure of the 1st modification of the harmonics reduction part in Embodiment 1. The figure which shows the structure of the 2nd modification of the harmonics reduction part in Embodiment 1. The figure which shows the structure of the 3rd modification of the harmonics reduction part in Embodiment 1. The figure which shows the structure of the 4th modification of the harmonics reduction part in Embodiment 1. The figure which shows the structure of the modification of the frequency selection board in Embodiment 1. The figure which shows the structure of the 1st surface of the frequency selection board in Embodiment 2. The figure which shows the cross section of the frequency selection board in Embodiment 2 The figure which shows the structure of the 2nd surface of the frequency selection board in Embodiment 2. The figure which shows the structure at the time of arrange | positioning the frequency selection board in Embodiment 2 in a radome.

  Hereinafter, a frequency selection plate and an electronic circuit according to an embodiment of the present invention will be described in detail based on the drawings. The present invention is not limited by the embodiment.

Embodiment 1
FIG. 1 is a diagram showing the configuration of the frequency selection plate 1 according to the first embodiment. In the frequency selection plate 1, a plurality of lines 11 configured by an element conductor pattern 12 and a connection portion 13 connecting a plurality of adjacent element conductor patterns 12 are arranged in parallel.

  The plurality of element conductor patterns 12 and the plurality of connection portions 13 are formed by etching on the surface 10 a of the base material 10 of the dielectric substrate.

  FIG. 2 is a diagram showing the configuration of the connection portion 13 which is an electronic circuit. The connection part 13 is provided with the diode 14 which is an active element, and the harmonics reduction part 15 arrange | positioned at at least one of the diode 14 as shown in FIG.

  The harmonic reduction unit 15 is disposed at least one of between the diode 14 and the first element conductor pattern 12 a and between the diode 14 and the second element conductor pattern 12 b. In the following, the first element conductor pattern 12a is referred to as an element conductor pattern 12a. The second element conductor pattern 12b is referred to as an element conductor pattern 12b. The harmonics reduction unit 15 reduces harmonics generated by the diode 14. The principle of generation of harmonics by the diode 14 will be described later.

  In the example shown in FIG. 2, the harmonic reduction unit 15 is configured of a first harmonic reduction unit 15 a and a second harmonic reduction unit 15 b. The first harmonic reduction unit 15 a is disposed between the element conductor pattern 12 a and the diode 14. The second harmonic reduction unit 15b is disposed between the diode 14 and the element conductor pattern 12b. In the example shown in FIG. 2, the element conductor pattern 12 connected to the first harmonic reduction portion 15a side is an element conductor pattern 12a, and the element conductor pattern 12 connected to the second harmonic reduction portion 15b is an element conductor pattern It is 12b.

  The first harmonic reduction unit 15a and the second harmonic reduction unit 15b each have a first conductor 115a whose one end is connected to the element conductor pattern 12, and a second conductor 115b parallel to the first conductor 115a. The third conductor 115 c connects the other end of the first conductor 115 a and the second conductor 115 b. The first conductor 115a and the second conductor 115b are set to a length of 1⁄4 of the wavelength corresponding to the frequency of the harmonic, and function as a parallel short of tip short. The first harmonic reduction unit 15a and the second harmonic reduction unit 15b are formed on the surface 10a of the base 10 of the dielectric substrate by etching. In the present embodiment, "115a" is described as a first conductor and "115b" is described as a second conductor, but "115a" is a second conductor and "115b" is a first conductor. It is also good.

  Although FIG. 2 shows an example in which two harmonics reduction units of the first harmonics reduction unit 15a and the second harmonics reduction unit 15b are provided, the number of harmonics reduction units may be one. FIG. 3 is a view showing the configuration of a modification of the connection portion 13. In the example shown in FIG. 3, the harmonic reduction unit 15 is disposed on the cathode side which is one end side of the diode 14. The reason why the harmonic reduction unit 15 is disposed on the cathode side will be described later.

  As shown in FIG. 1, the frequency selection plate 1 includes a first control bias line 16 connected to the positive side of the power supply unit 21 and a second control bias line 17 connected to the negative side of the power supply unit 21. . The power supply unit 21 applies a voltage in the forward direction to the diode 14 of the connection unit 13. Hereinafter, a state in which a voltage is applied to the frequency selection plate 1 from the power supply unit 21 is referred to as an ON (on) state, and a state in which no voltage is applied to the frequency selection plate 1 from the power supply unit 21 is off (off) state It is said. In addition, the control unit 22 performs control to switch between the ON state and the OFF state of the power supply unit 21.

  Each line 11 has one end 11 a connected to the first control bias line 16 and the other end 11 b connected to the second control bias line 17.

  The distance d between the lines 11 is defined based on the wavelength corresponding to the specific frequency that the frequency selection plate 1 transmits or reflects. For example, the distance d between the lines 11 is 1/10 of the wavelength corresponding to the specific frequency that the frequency selection plate 1 transmits or reflects.

  Next, the operation of the frequency selection plate 1 when the radio wave output from the external radar device arrives at the frequency selection plate 1 will be described. The incoming wave is assumed to be a horizontal polarization in which the vibration direction of the electric field is horizontal to the ground surface. It is assumed that the polarization plane of the incoming wave and the direction of the current flowing through the diode 14 are parallel.

  First, when the power supply unit 21 is in the ON state, a voltage is applied to the first control bias line 16, a current flows through the diode 14, and the element conductor patterns 12 adjacent in the horizontal direction electrically short.

  As described above, the distance d between the lines 11 is 1/10 the length of the wavelength corresponding to the specific frequency that the frequency selection plate 1 transmits or reflects, and the incoming wave of the specific frequency is It is set shorter than the length of the wavelength corresponding to the frequency. The specific frequency is set to the frequency of the incoming wave that is to be transmitted or reflected by the frequency selection plate 1. The frequency of the incoming wave that is to be transmitted or reflected by the frequency selection plate 1 is hereinafter referred to as the frequency of the incoming wave.

  When the power supply unit 21 is in the ON state, the surface on which the line 11 of the frequency selection plate 1 is formed is equivalently regarded as a metal conductor surface at the frequency of the incoming wave. Therefore, when the power supply unit 21 is in the ON state, the incoming wave is reflected by the frequency selection plate 1.

  On the other hand, when the power supply unit 21 is in the OFF state, no current flows in the diode 14, and the element conductor patterns 12 adjacent in the horizontal direction are electrically opened. In this case, the surface on which the line 11 of the frequency selection plate 1 is formed is not equivalently regarded as a metal conductor surface at the frequency of the incoming wave. Therefore, when the power supply unit 21 is in the OFF state, the incoming wave passes through the frequency selection plate 1.

  Next, the operation when the frequency selection plate 1 is disposed in the radome 31 will be described. FIG. 4 is a view showing how the frequency selection plate 1 is disposed in the radome 31. As shown in FIG.

  In the radome 31, a frequency selection plate 1, a power supply unit 21, a control unit 22, and a radar antenna unit 32 are disposed. The radome 31 protects the radar antenna unit 32 from being hit by wind or rain. The frequency selection plate 1 is disposed in front of the radar antenna unit 32. The frequency selection plate 1 is inclined relative to the radar antenna unit 32 by a predetermined angle. As the frequency selective plate 1 is inclined, the incoming wave is reflected in a direction different from the incoming direction.

  Here, the operation of the frequency selection plate 1 when receiving an incoming wave by the radar antenna unit 32 or when the radar antenna unit 32 does not operate will be described.

  When the power supply unit 21 is in the ON state, the frequency selection plate 1 reflects the incoming wave in a direction different from the incoming direction. Therefore, the radar reflection cross section (RCS: Radar Cross Section) of the aperture surface of the radar antenna unit 32 can be reduced. The radar reflection cross section is a measure of the ability of the radio wave output from the radar device to reflect on the object.

  Moreover, the frequency selection board 1 permeate | transmits an arrival wave, when the power supply part 21 is an OFF state.

  Therefore, the frequency selection board 1 can switch the reflection characteristic and the transmission characteristic in the same frequency band by switching the ON state and the OFF state of the power supply unit 21. Even if the frequency band used by the antenna unit 32 for radar and the frequency band used by the external radar device are the same, the frequency selection plate 1 determines that the arrival wave from the external radar device is the arrival direction By reflecting in different directions, RCS of the aperture plane of the antenna unit 32 for radar can be reduced.

  Next, the operation of the frequency selection plate 1 when radio waves are emitted from the radar antenna unit 32 will be described using FIG. FIG. 5 is a diagram showing how an alternating high frequency signal S1 propagates on the line 11. As shown in FIG.

  When radio waves are radiated from the radar antenna unit 32, the high power transmission wave S 0 passes through the frequency selection plate 1.

  A part of the high power transmission wave S 0 is received by the element conductor pattern 12 a of the frequency selection plate 1. The alternating high frequency signal S 1 received by the element conductor pattern 12 a is propagated to the connection portion 13. Below, the connection part 13 shall be comprised by the 1st harmonic reduction part 15a, the diode 14a, and the 2nd harmonic reduction part 15b.

  In addition, the first conductor 115a and the second conductor 115b of the first harmonic reduction unit 15a are shorter than the length of the wavelength corresponding to the frequency of the high frequency signal S1. Thus, the high frequency signal S1 propagates to the diode 14a without being affected by the first harmonic reduction unit 15a.

  The diode 14a is one of semiconductor devices, and operates with direct current with a rectifying effect. The high frequency signal S1 is converted into a direct current signal by the rectification effect of the diode 14a. When the high frequency signal S1 is converted to a direct current signal, a harmonic S2 is generated.

  Before propagating to the element conductor pattern 12b adjacent to the connection portion 13, the harmonic wave S2 passes through the second harmonic reduction portion 15b. The first conductor 115 a and the second conductor 115 b of the second harmonic reduction unit 15 b are formed to have a length of 1⁄4 of the wavelength corresponding to the frequency of the harmonic, and the tip short circuit is parallel Work in two lines. The harmonic S2 is reduced by the cancellation effect at the root of this parallel double line.

  The harmonic wave S3 propagated to the element conductor pattern 12b is small, and the unnecessary wave S4 radiated from the element conductor pattern 12b is also small. The harmonics S3 are reduced by the first harmonic reduction unit 15a disposed on the cathode side of the diode 14b adjacent to the element conductor pattern 12b. In addition, when the harmonics reduction part 15 is comprised by either one of the 1st harmonics reduction part 15a and the 2nd harmonics reduction part 15b, in order to reduce propagation of the harmonics to element conductor pattern 12 It is better to dispose the second harmonic reduction unit 15 b on the cathode side of the diode 14.

  Thus, even if radio waves are radiated from the antenna unit 32 for radar and the harmonics are generated by the diode 14, the frequency selection plate 1 can suppress the harmonics by the second harmonic reduction unit 15b. This effect can be realized without degrading the performance of the radar antenna unit 32.

  Also, the frequency band used by the radar antenna unit 32 and the frequency band used by the external radar device are not the same. For example, the frequency band used by the radar antenna unit 32 is on the high band side, Even if the frequency band used by the external radar device is on the low band side, the reflection and transmission of the incoming wave can be switched by switching the ON state and the OFF state of the power supply unit 21.

  Further, as harmonics, there are even harmonics such as 2nd harmonic and 4th harmonic and odd harmonics such as 3rd harmonic and 5th harmonic. The configuration of the harmonics reduction unit 15 corresponding to the even harmonics and the odd harmonics will be described below.

  FIG. 6 is a diagram showing the configuration of a first modification of the harmonics reduction unit 15. As shown in FIG. The harmonic reduction unit 15 includes even harmonic reduction units 41a and 41b that reduce even harmonics and odd harmonic reduction units 42a and 42b that reduce odd harmonics.

  The even harmonic reduction unit 41 a is disposed on the anode side of the diode 14. The even harmonic reduction unit 41 b is disposed on the cathode side of the diode 14. The odd harmonic reduction unit 42a is disposed between the even harmonic reduction unit 41a and the element conductor pattern 12a. The odd harmonic reduction unit 42b is disposed between the even harmonic reduction unit 41b and the element conductor pattern 12b.

  Below, the other modification of the harmonics reduction part 15 is demonstrated. The even harmonic reduction units 41a and 41b and the odd harmonic reduction units 42a and 42b may be arranged as shown in FIG. 7, FIG. 8 or FIG. FIG. 7 is a diagram showing the configuration of a second modification of the harmonics reduction unit 15. As shown in FIG. The odd harmonic reduction unit 42 a is disposed on the anode side of the diode 14. The odd harmonic reduction unit 42 b is disposed on the cathode side of the diode 14. The even harmonics reduction unit 41a is disposed between the odd harmonics reduction unit 42a and the element conductor pattern 12a. The even harmonics reduction unit 41 b is disposed between the odd harmonics reduction unit 42 b and the element conductor pattern 12 b.

  FIG. 8 is a diagram showing the configuration of a third modification of the harmonics reduction unit 15. As shown in FIG. The even harmonic reduction unit 41 is disposed on the cathode side of the diode 14. The odd harmonic reduction unit 42 is disposed between the even harmonic reduction unit 41 and the element conductor pattern 12 b.

  FIG. 9 is a diagram showing the configuration of a fourth modification of the harmonics reduction unit 15. As shown in FIG. The odd harmonic reduction unit 42 is disposed on the cathode side of the diode 14. The even harmonic reduction unit 41 is disposed between the odd harmonic reduction unit 42 and the element conductor pattern 12 b.

  Further, the even harmonic reduction units 41, 41a, and 41b set the length to 1/4 of the wavelength corresponding to the frequency of the even harmonics. For example, in order to reduce double harmonics, the even harmonic reduction units 41, 41a and 41b set the length to 1⁄4 of the wavelength corresponding to the double harmonic frequency, and In order to reduce the double harmonics, the length is set to 1⁄4 of the wavelength corresponding to the frequency of the quadruple harmonics. The odd harmonics reduction units 42, 42a, 42b set the length to 1⁄4 of the wavelength corresponding to the frequency of the harmonics of the odd multiple. For example, when reducing the triple harmonics, the odd harmonics reduction units 42, 42a, 42b set the length to 1⁄4 of the wavelength corresponding to the triple harmonic frequency, and In order to reduce the double harmonics, the length is set to 1⁄4 of the wavelength corresponding to the frequency of the 5-fold harmonic.

  According to such a configuration, the frequency selection plate 1 can efficiently reduce even harmonics and odd harmonics.

  As described above, the distance d between the lines 11 is set to a length such as 1/10 of the length of the wavelength corresponding to the specific frequency that the frequency selection plate 1 transmits or reflects, and corresponds to the specific frequency. It is set narrower than the wavelength length. However, when the frequency selection plate 1 is disposed in front of the radar antenna unit 32, the area of the frequency selection plate 1 also increases in proportion to the size of the aperture area of the radar antenna unit 32. Then, when the aperture area of the radar antenna unit 32 is large, the number of the diodes 14 mounted on each of the lines 11 increases with the increase of the number of the lines 11 formed on the frequency selection plate 1, and the frequency selection plate The manufacturing cost of 1 is high.

  Therefore, in the frequency selection plate 1, the connection portion 13 is not disposed, and the first line 111 a including the adjacent element conductor patterns 12 and the second line 111 b where the adjacent element conductor patterns 12 are connected by the connection portion 13. Configure. FIG. 10 is a view showing a configuration of a frequency selection plate 50 which is a modification of the frequency selection plate 1.

  That is, as compared with the case where the diodes 14 are mounted on all the lines 11, the frequency selective plate 1 configured by the first line 111a and the second line 111b is manufactured while maintaining the reflection characteristic and the transmission characteristic. Cost can be reduced.

  In the example shown in FIG. 10, the first lines 111a in which the diodes 14 are not mounted are arranged in every other column, and the thinning rate of the diodes 14 is 50%. The thinning rate may be determined.

  Although a linear shape is shown as an example of the shape of the element conductor pattern 12 in FIG. 1, the shape of the element conductor pattern 12 is not limited to the linear shape. For example, the shape of the element conductor pattern 12 may be a shape in which the line width is increased, a shape in which a slit is cut in the middle of the line, a shape in which the line is expanded in a tapered shape, or a shape in which the line is narrowed in a tapered shape .

  Depending on the shape of the element conductor pattern 12, the frequency of the incoming wave to be reflected or transmitted changes, and the amount of reflection or transmission of the incoming wave also changes. Therefore, the shape of the element conductor pattern 12 is determined at design time based on the frequency of the incoming wave to be reflected or transmitted.

  In the above description, the configuration of the frequency selection plate 1 has been described in which harmonics are reduced and RCS of the aperture plane of the radar antenna unit 32 is reduced in the case where the incoming wave is horizontal polarization. When the incoming wave is vertically polarized, the polarization plane of the incoming wave and the direction of the current flowing through the diode 14 can be made parallel by rotating the frequency selection plate 1 by 90 degrees. Vertical polarization is polarization in which the vibration direction of the electric field is perpendicular to the ground surface. Therefore, the frequency selective plate 1 can reduce harmonics and reduce RCS of the aperture plane of the antenna unit 32 for radar as well as the above for the incoming wave of vertical polarization.

  When used in an environment where high power transmission waves are not irradiated, the frequency selection plate 1 according to the first embodiment switches the reflection or transmission of the incoming wave by switching the ON state and the OFF state by the power supply unit 21. be able to. Further, the frequency selection plate 1 can reduce the RCS of the aperture surface of the radar antenna unit 32, and operates the radar antenna unit 32 in the same frequency band as the frequency band used by the external radar device. Can. The environment in which the high power transmission wave is not irradiated is, for example, an environment in which the frequency selection plate 1 is obliquely disposed in front of the passive radar device. The passive radar device is a device that does not emit radio waves by itself but receives radio waves from a target to detect the target.

  When the frequency selection plate 1 in the first embodiment is used in an environment where a high power transmission wave is irradiated, the connection portion 13 is configured by the harmonic reduction portion 15 and the diode 14 which is an active element, By switching the ON state and the OFF state by the unit 21, it is possible to switch the reflection or transmission of the incoming wave. Further, the frequency selection plate 1 can reduce the RCS of the aperture surface of the radar antenna unit 32, and operates the radar antenna unit 32 in the same frequency band as the frequency band used by the external radar device. Can. The environment in which the high power transmission wave is irradiated is, for example, an environment in which the frequency selection plate 1 is obliquely disposed in front of the active radar device. The active radar device is a device that emits radio waves and receives the reflected waves to detect a target.

  In the frequency selective plate 1 in the first embodiment, when radio waves are radiated from the antenna unit 32 for radar and a high power transmission wave is irradiated, harmonics of the induced current are generated by the rectification effect of the diode 14, but harmonics are reduced The harmonics can be suppressed by the unit 15. Therefore, since the frequency selection plate 1 in the embodiment 1 can reduce harmonics propagated to the element conductor pattern 12, the element conductor pattern 12 causes harmonics without deteriorating the performance of the radar antenna section 32. It can reduce that a wave is radiated as an unnecessary wave.

  As a first modification of the harmonics reduction unit 15, the frequency selection plate 1 in the first embodiment includes the even harmonics reduction units 41a and 41b between the diode 14 and the odd harmonics reduction units 42a and 42b. The odd harmonics reducing units 42a and 42b are disposed between the even harmonics reducing units 41a and 41b and the element conductor pattern 12a. As a second modification of the harmonics reduction unit 15, the frequency selection plate 1 in the first embodiment includes the odd harmonics reduction units 42a and 42b between the diode 14 and the even harmonics reduction units 41a and 41b. The even number harmonics reduction units 41a and 41b are arranged between the odd numbered harmonics reduction units 42a and 42b and the element conductor pattern 12a. As a third modification of the harmonics reduction unit 15, the frequency selective plate 1 according to the first embodiment has an even harmonic reduction unit 41 disposed on the cathode side of the diode 14, and an even harmonic reduction unit 41 and an element The odd harmonics reduction unit 42 is disposed between the conductor pattern 12 b and the conductor pattern 12 b. As a fourth modification of the harmonics reduction unit 15, the frequency selection plate 1 in the first embodiment arranges the odd harmonics reduction unit 42 on the cathode side of the diode 14, and the odd harmonics reduction unit 42 and the element The even harmonic reduction unit 41 is disposed between the conductor pattern 12 b and the conductor pattern 12 b. Therefore, the frequency selection plate 1 in the first embodiment can efficiently reduce even harmonics and odd harmonics.

  The frequency selection plate 50 in the first embodiment is formed of the first line 111 a formed of the adjacent element conductor patterns 12 and the second line 111 b connected to the adjacent element conductor patterns 12 by the connection portion 13. The number of diodes 14 can be reduced while maintaining the reflection and transmission characteristics, and the manufacturing cost can be reduced.

  Especially in the case where the frequency band used by the antenna unit 32 for radar and the frequency band used by the external radar device are the same, the frequency selection plate 1 in the first embodiment suppresses the generation of unnecessary waves, The RCS of the aperture plane of the radar antenna unit 32 can be reduced.

Second Embodiment
The frequency selective plate 60 in the second embodiment differs from the frequency selective plate 1 in the first embodiment in that the lines are formed on both the front surface 10 a and the back surface 10 b of the base material 10. Hereinafter, the same components as those of the frequency selection plate 1 according to the first embodiment are denoted by the same reference numerals.

  11, 12 and 13 are diagrams showing the configuration of the frequency selection plate 60 in the second embodiment. FIG. 11 is a diagram showing the configuration of the first surface 60 a of the frequency selection plate 60. FIG. 12 is a view showing a cross section of the frequency selection plate 60. As shown in FIG. FIG. 13 is a view showing a configuration of a second surface 60 b which is a back surface of the first surface 60 a of the frequency selection plate 60.

  The configuration of the first surface 60 a of the frequency selection plate 60 will be described. As shown in FIG. 11, in the first surface 60a of the frequency selection plate 60, the line 11 constituted by the element conductor pattern 12 and the connection portion 13 connecting the adjacent element conductor patterns 12 is in the first direction. They are arranged side by side in parallel. In FIG. 11, the line 11, the first control bias line 71, and the second control bias line 72, which are formed on the second surface 60b, are shown transparently by broken lines. The plurality of element conductor patterns 12 and the plurality of connection portions 13 are formed by etching on the surface 10 a of the base material 10 of the dielectric substrate.

  The first surface 60 a of the frequency selection plate 60 includes a first control bias line 61 connected to the positive side of the power supply unit 21 and a second control bias line 62 connected to the negative side of the power supply unit 21. Each line 11 of the first surface 60 a of the frequency selection plate 60 has one end 11 a connected to the first control bias line 61 and the other end 11 b connected to the second control bias line 62. The power supply unit 21 applies a voltage in the forward direction to the diode 14 of the connection unit 13.

  The distance d between the lines 11 of the first surface 60 a of the frequency selection plate 60 is defined based on the wavelength corresponding to the specific frequency that the frequency selection plate 60 transmits or reflects. For example, the distance d between the lines 11 of the first surface 60 a of the frequency selection plate 60 is 1/10 of the wavelength corresponding to the specific frequency that the frequency selection plate 1 transmits or reflects.

  Next, the configuration of the second surface 60 b of the frequency selection plate 60 will be described. In the second surface 60b of the frequency selection plate 60, as shown in FIG. 13, the line 11 constituted by the element conductor pattern 12 and the connection portion 13 connecting the adjacent element conductor patterns 12 is in the second direction They are arranged side by side in parallel. In FIG. 13, the line 11, the first control bias line 61, and the second control bias line 62, which are formed on the first surface 60a, are shown transparently by broken lines. The plurality of element conductor patterns 12 and the plurality of connection portions 13 are formed by etching on the back surface 10 b of the base 10 of the dielectric substrate.

  The second surface 60 b of the frequency selection plate 60 includes a first control bias line 71 connected to the positive side of the power supply unit 21 and a second control bias line 72 connected to the negative side of the power supply unit 21. Each line 11 of the second surface 60 b of the frequency selection plate 60 has one end 11 a connected to the first control bias line 71 and the other end 11 b connected to the second control bias line 72. The power supply unit 21 applies a voltage in the forward direction to the diode 14 of the connection unit 13.

  The distance d between the lines 11 of the second surface 60b of the frequency selection plate 60 is defined based on the wavelength corresponding to the specific frequency that the frequency selection plate 1 transmits or reflects. For example, the distance d between the lines 11 of the second surface 60b of the frequency selection plate 60 is 1/10 of the wavelength corresponding to the specific frequency that the frequency selection plate 1 transmits or reflects.

  As shown in FIGS. 11 and 13, the first direction in which the line 11 of the first surface 60a of the frequency selection plate 60 is disposed and the line 11 in the second surface 60b of the frequency selection plate 60 are disposed. And the orthogonal second direction.

  The first surface 60a of the frequency selection plate 60 reflects or transmits the horizontal polarization of the incoming wave. The second surface 60b of the frequency selective plate 60 reflects or transmits the vertical polarization of the incoming wave.

  Here, the operation of the frequency selection plate 60 will be described. When radio waves of a specific frequency arrive at the first surface 60a or the second surface 60b of the frequency selection plate 60, the power supply unit 21 is switched between the ON state and the OFF state as described in the first embodiment. Thus, it is possible to switch between reflection and transmission of radio waves of a specific frequency.

  Further, the frequency selection plate 60 can switch the ON state and the OFF state of the power supply unit 21 independently of each of the first surface 60 a and the second surface 60 b of the frequency selection plate 60. However, in many cases, the polarization direction of the incoming wave can not be identified. Therefore, the first surface 60 a and the second surface 60 b of the frequency selection plate 60 are synchronized to switch the ON state and the OFF state of the power supply unit 21. That is, when the power supply unit 21 is in the ON state, a voltage is applied to the first control bias line 61 and the first control bias line 71. Further, when the power supply unit 21 is in the OFF state, no voltage is applied to the first control bias line 61 and the first control bias line 71.

  Therefore, frequency selective plate 60 can simultaneously reflect or transmit horizontal polarization and vertical polarization of the incoming wave, and has an advantage of being able to cope with arbitrary polarization as compared with frequency selective plate 1 in the first embodiment. .

  Next, the operation when the frequency selection plate 60 is disposed in the radome 31 will be described. FIG. 14 is a view showing how the frequency selection plate 60 is disposed in the radome 31. As shown in FIG.

  In the radome 31, a frequency selection plate 60, a power supply unit 21, a control unit 22, and a radar antenna unit 32 are disposed. The frequency selection plate 60 is disposed in front of the radar antenna unit 32. The frequency selection plate 60 is inclined by a predetermined angle. Because the frequency selection plate 60 is inclined, the incoming wave is reflected by the frequency selection plate 60 in a direction different from the direction of arrival.

  Here, the operation of the frequency selection plate 60 when receiving an incoming wave by the radar antenna unit 32 or when the radar antenna unit 32 does not operate will be described.

  When the power supply unit 21 is in the ON state, the frequency selection plate 60 reflects the arrival waves of orthogonal two polarized waves in a direction different from the arrival direction, so RCS of the aperture plane of the radar antenna unit 32 can be reduced. . The orthogonal two-polarization refers to polarization including horizontal polarization in which the vibration direction of the electric field is horizontal to the ground surface and vertical polarization in which the vibration direction of the electric field is perpendicular to the ground surface.

  Further, the frequency selection plate 60 transmits the incoming wave when the power supply unit 21 is in the OFF state.

  Even when the frequency used by the antenna unit 32 for radar and the frequency used by the external radar device are the same, the frequency selection plate 60 is orthogonal by switching the ON state and the OFF state of the power supply unit 21. It is possible to switch between reflection and transmission of the incoming wave of two polarization components.

  Even if the frequency band used by the antenna unit 32 for radar and the frequency band used by the external radar device are the same, the frequency selection plate 60 can reduce the RCS of the aperture plane of the antenna unit 32 for radar it can. This effect can be realized without degrading the performance of the radar antenna unit 32.

  The operation of the frequency selection plate 60 when emitting radio waves from the radar antenna unit 32 is the same as the operation of the frequency selection plate 1 in the first embodiment. Therefore, even if radio waves are radiated from the antenna unit 32 for radar and the harmonics are generated by the diode 14, the frequency selection plate 60 can suppress the harmonics by the harmonics reduction unit 15, and the radiation from the element conductor pattern 12 The unnecessary wave can be reduced.

  The shape of the element conductor pattern 12 is not limited to the linear shape. For example, the shape of the element conductor pattern 12 may be a shape in which the line width is increased, a shape in which a slit is cut in the middle of the line, a shape in which the line is expanded in a tapered shape, or a shape in which the line is narrowed in a tapered shape .

  Depending on the shape of the element conductor pattern 12, the frequency of the incoming wave to be reflected or transmitted changes, and the amount of reflection or transmission of the incoming wave also changes. Therefore, the shape of the element conductor pattern 12 is determined at design time based on the frequency of the incoming wave to be reflected or transmitted.

  In the frequency selection plate 60 in the second embodiment, the arrangement direction of the lines 11 arranged on the first surface 60a and the arrangement direction of the lines 11 arranged on the second surface 60b are orthogonal to each other. For example, the frequency selection plate 60 can reflect horizontally polarized waves of incoming waves by the first surface 60 a and can reflect vertically polarized waves of incoming waves by the second surface 60 b. Further, the frequency selective plate 60 can transmit the horizontal polarization of the incoming wave through the first surface 60 a and can transmit the vertical polarization of the incoming wave through the second surface 60 b.

  The frequency selective plate 60 according to the second embodiment reflects the incoming waves of orthogonal two polarized waves in a direction different from the direction of arrival, so that the RCS of the aperture plane of the radar antenna unit 32 can be reduced. The radar antenna unit 32 can be operated in the same frequency band as the frequency band used by the device.

  In the frequency selection plate 60 in the second embodiment, radio waves are radiated from the antenna unit 32 for radar, and when a high power transmission wave is irradiated, harmonics of orthogonal two polarized waves of induced current are generated by the rectification effect of the diode 14 However, the harmonics reduction unit 15 can suppress harmonics of orthogonal two polarized waves. Therefore, the frequency selection plate 60 in the second embodiment can reduce harmonics of orthogonal two polarized waves propagated to the element conductor pattern 12, and the element conductor does not deteriorate the performance of the radar antenna unit 32. The pattern 12 can reduce the emission of harmonics of orthogonal two polarized waves as unnecessary waves.

  The frequency selective plate 60 according to the second embodiment can efficiently reduce even harmonics of the orthogonal two polarized waves and odd harmonics of the orthogonal two polarized waves.

  In the frequency selection plate 60 in the second embodiment, the connection portion 13 is not disposed, and the first line formed of the adjacent element conductor patterns 12 and the second line in which the adjacent element conductor patterns 12 are connected by the connection portion 13. And the first line formed of the element conductor pattern 12 and the second line in which the adjacent element conductor patterns 12 are connected by the connection section 13. And the number of diodes 14 on both the front surface 10a and the back surface 10b of the base 10 can be reduced while maintaining the reflection characteristic and the transmission characteristic. Can be reduced.

  Especially in the case where the operating frequency band of the antenna unit 32 for radar and the operating frequency band of the external radar device are the same, the frequency selection plate 60 in the second embodiment suppresses generation of unnecessary waves for two orthogonal polarizations. The RCS of the aperture plane of the radar antenna unit 32 can be reduced.

  The configuration shown in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and one of the configurations is possible within the scope of the present invention. Parts can be omitted or changed.

  1,50,60 frequency selective plate, 10 base materials, 11 lines, 12, 12a, 12b element conductor patterns, 13 connections, 14 diodes, 15 harmonics reduction units, 15a first harmonics reduction units, 15b second harmonics Wave reduction unit 16, 16, 71 71 first control bias line 17, 62, 72 second control bias line 21 power supply unit 22 control unit 31 radome 32 radar antenna unit 41 41a 41b even multiples Harmonic reduction part 42, 42a, 42b odd harmonic reduction part 60a first surface 60b second surface 111a first line 111b second line 115a first conductor 115b second conductor , 115c third conductor.

Claims (7)

A plurality of lines formed of an element conductor pattern and a connection portion connecting the adjacent first element conductor pattern and the second element conductor pattern are arranged in parallel,
The connection is
Active element,
A harmonic reduction unit disposed on at least one of the active element and the first element conductor pattern, and the active element and the second element conductor pattern. Frequency selection board.   The harmonic reduction portion includes a first conductor whose one end is connected to the element conductor pattern, a second conductor parallel to the first conductor, the other end of the first conductor, and the second conductor. The frequency selective board according to claim 1, characterized by comprising a third conductor which connects with the conductor.   The frequency according to claim 2, wherein the length of the line of each of the first conductor and the second conductor is 1/4 the length of the wavelength corresponding to the frequency of the harmonic. Choice board.   The harmonic reduction unit includes an even harmonic reduction unit that reduces even harmonics and an odd harmonic reduction unit that reduces odd harmonics. , 2 or 3 frequency selective plate.   The said line is comprised from the 1st line which consists of the said adjacent element conductor pattern, and the 2nd line by which the said adjacent element conductor pattern is connected by the said connection part. The frequency selective plate according to any one of the preceding claims. The track is disposed on a first side and a second side of the substrate,
The arrangement direction of the said line arrange | positioned at the said 1st surface and the arrangement direction of the said line arrange | positioned at the said 2nd surface are orthogonally crossing, It is characterized by the above-mentioned. The frequency selection board as described in 1 paragraph. Active element,
And a harmonic reduction unit connected to the active element through a conductor formed at an end of the active element,
The harmonic reduction unit includes a first conductor connected at one end to a conductor formed at an end of the active element, a second conductor parallel to the first conductor, and the first conductor. An electronic circuit comprising: a third conductor connecting the other end of the second conductor and the other end of the second conductor.

Images