JP5371384B2 - Waveguide circuit element and waveguide structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve withstand voltage, by employing in advance a structure for relieving the electric field concentration (current concentration), in an electric field concentration region in advance. <P>SOLUTION: The waveguide circuit element 1 has opposite surfaces 1a, 1b that are parallel to each other in the inside and is made of a metal member in which a resonant space for resonating an electromagnetic wave of the fundamental wavelength is formed, wherein a round hole 2 is formed, by removing the metal member on one of the opposite surfaces corresponding substantial to the center region as an electric field concentration region, at which the electric field strength in the fundamental wavelength becomes maximum. The round hole 2 relieves the current concentration, and as a result, the electric field concentration can be relieved. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a waveguide circuit element and a waveguide structure having a resonance space for resonating an electromagnetic wave having a fundamental wavelength.

  A waveguide circuit generally has higher power handling performance than a microstrip line or the like. For example, a resonator or a filter device using the waveguide circuit has a portion where an electric field is concentrated, and a discharge is generated in that portion. There is a problem that it is likely to occur and the power durability is lower than that of a normal waveguide. Conventionally, in order to solve such a problem, measures have been taken such as avoiding the provision of a protruding portion where the electric field concentrates on a stub or the like, or increasing the size of the waveguide.

Patent Document 1 describes a band element filter having a structure in which a plurality of stages of resonators are joined to an outer wall of a main waveguide. A window portion is formed by two circular holes on the joint surface with each resonator. Two circular holes are formed symmetrically with respect to the central part of the main waveguide, ensuring maximum current flow at the maximum electric field strength, preventing arcing at the window, and for high power The band rejection filter is realized.
Japanese Patent Laid-Open No. 11-274817

  However, the conventional measures such as adopting the inner slab of the protrusion or increasing the waveguide dimension have a problem in that there are large restrictions in size and processing. Further, in the structure of Patent Document 1, although the electric field resistance performance at the junction with the resonator can be improved, the electric field resistance performance of the resonator itself is not described.

  The present invention has been made in view of the above, and provides a waveguide circuit element and a waveguide structure having high power resistance by adopting a structure that relaxes electric field concentration in advance in an electric field concentration region.

According to a first aspect of the present invention, there is provided a waveguide circuit element comprising a metal member having internal opposing surfaces separated from each other by a predetermined height and having a resonance space for resonating an electromagnetic wave having a fundamental wavelength. In the resonance space, a hole penetrating to the outside of the metal member is provided in one of the opposing surfaces corresponding to the electric field concentration region where the electric field intensity at the fundamental wavelength is maximum. .

In the resonance space formed inside the metal member, for example, when TE ^{○ 101} mode resonance occurs, a region in which the electric field strength peaks is generated at the substantially central portion of the opposed surfaces facing each other with a predetermined height dimension. . When the electric field strength increases, a discharge phenomenon occurs between the opposing surfaces, and resonance cannot be sustained. Therefore, the shape of the facing surface corresponding to the region where the electric field strength concentrates in the resonance space is changed to reduce the concentration of current that causes the electric field concentration. For example, the metal material on at least one of the opposing surfaces is removed by drilling into a part of a sphere or a mortar shape to form a hole that communicates with the outside, thereby reducing current concentration . If this is because no current flows in the portion of the hole, current concentration can be effectively relaxed. As described above, by reducing current concentration on at least one of the opposing surfaces of the electric field concentration portion, the electric field concentration is reduced and the power durability performance is improved.

According to a second aspect of the invention, the waveguide circuit device of claim 1, wherein the cross-sectional shape of the front Kiana is set to dimension the radiation of electromagnetic wave is limited of the fundamental wavelength through the pores It is characterized by being. According to this configuration, the current does not flow through the hole due to the hole, so that the current concentration is reduced, and as a result, the electric field concentration is reduced. In addition, when the hole has a cross-sectional shape, for example, when the hole is circular, the diameter of the hole is set to a size at which the electromagnetic wave having the fundamental wavelength cannot pass through the hole (blocking), so that no power loss occurs. The power durability can be improved.

According to a third aspect of the present invention, in the waveguide circuit element according to the first or second aspect, the metal member includes first and second metal blocks facing each other, and the first and second metal layers. A partition plate interposed between the locks, and at least one of the resonance spaces is mirror-symmetrically formed on the opposing surface side of the first and second metal blocks with the partition plate interposed therebetween. , the partition plate is coupled windows for coupling said resonant space formed on both sides is formed, and the hole is characterized in that it is formed in the partition plate. According to this configuration, a waveguide circuit element such as a filter having at least two resonators is formed by forming a hole in the partition plate sandwiched between the first and second metal blocks. However, the formation of the holes is facilitated.

According to a fourth aspect of the present invention, one of the resonance spaces of the waveguide circuit element according to any one of the first to third aspects is connected to a main waveguide that transmits the fundamental frequency via a main coupling window. In the waveguide structure, the hole is formed in one of the opposing surfaces forming the one resonance space. According to this configuration, since the hole is formed in the facing surface of the one resonance space serving as the input portion, a structure for reducing electric field concentration is effectively employed for the resonance space where the power is maximum.

According to a fifth aspect of the present invention, in the waveguide structure according to the fourth aspect, a cut-off portion is continuously provided at an appropriate side surface of the one resonance space. According to this configuration, in the aspect in which the hole is provided in the resonance space serving as the input portion, the electromagnetic wave from the main waveguide and the electromagnetic wave in the resonance space interfere with each other at the main coupling window, and as a result, the location in the electric field is in the formation of the hole . It may be an inappropriate or difficult place. Therefore, it is only necessary to form a cut-off portion, shift the electric field concentration portion, and form a hole at the shifted position, so that the design of the hole is facilitated.

According to the first aspect of the present invention, it is possible to improve the power resistance performance by providing the hole for relaxing the electric field concentration in advance in the electric field concentration region in the resonance space .

  According to the second aspect of the present invention, the electric field concentration is effectively reduced by the holes. Further, by setting the dimensions such that the electromagnetic wave having the fundamental wavelength cannot pass through the hole (blocking), the power durability can be improved without causing power loss.

According to the third aspect of the present invention, since the hole is formed in the partition plate sandwiched between the first and second metal blocks, a waveguide such as a filter having at least two resonators is provided. Even in the case of a tube circuit element, a hole can be easily formed.

According to the fourth aspect of the invention, since the hole is formed in the facing surface of the one resonance space serving as the input portion, the electric field concentration can be effectively reduced with respect to the resonance space where the power is maximum. .

According to the fifth aspect of the present invention, it is only necessary to form the cut-off portion to shift the electric field concentration portion and form the hole at the shifted position, so that the design of the hole can be facilitated.

  FIG. 6 is a block diagram showing a configuration of a radar apparatus as an example of a microwave transceiver to which the waveguide circuit element or the like according to the present invention is applied. The high-frequency circuit unit of the radar apparatus includes a magnetron that oscillates using, for example, a 9.63 GHz microwave as a fundamental wave. The pulse driving circuit 52 generates a pulsed transmission signal having a predetermined width by intermittently driving the magnetron 51 at a predetermined cycle. The circulator 53 propagates the pulsed transmission signal from the magnetron 51 to a predetermined circuit side. The terminator 54 is connected to the circulator 53 and consumes unnecessary power. The filter 55 suppresses the passage of harmonics with respect to the fundamental wave. The suppressed harmonics are consumed by the terminator 54 via the circulator 53.

  The circulator 56 is for propagating the transmission signal to the transmission side and propagating the reception signal to the reception side. The rotary joint 57 is for electrically connecting the stationary system and the rotating system. The antenna 58 is rotated at a constant speed by a motor (not shown), and transmits a transmission signal outward as a radio wave pulse for detection. The reception system circuit 59 performs signal processing on the signal received by the antenna 58. The magnetron 51 to the antenna 58 and the antenna 58 to the limiter circuit 58 are constituted by waveguides.

  FIG. 1 is a diagram showing a structure of a first embodiment of a waveguide circuit element according to the present invention and its electric field distribution characteristics. FIG. 1 (a) is a structural diagram, and FIG. 1 (b) is an overall electric field. The distribution diagram, FIG. 1C, is a diagram showing the electric field intensity distribution in the II ′ section. 2 is a comparative example of FIG. 1 and shows a conventional general waveguide cavity resonator. FIG. 2 (a) is a structural diagram, FIG. 2 (b) is an overall electric field distribution diagram, and FIG. (C) is a figure which shows the electric field strength distribution in a II-II 'cross section.

  First, in FIG. 2A, the waveguide cavity resonator 100 has a substantially rectangular parallelepiped resonance space, the vertical and horizontal dimensions are set to 22.86 mm × 10.16 mm, and the height is the fundamental frequency. It is set to a dimension of 6 mm that allows microwaves with an in-tube wavelength corresponding to 9.63 GHz to pass. Inner wall surfaces (opposing surfaces) 100a and 100b that are spaced apart by this height dimension and are parallel to each other are formed. When electromagnetic waves are introduced into the resonance space, the current flows through the entire inner wall surface, but concentrates at the center of the opposing surfaces 100a and 100b. Therefore, as shown in FIG. 2B, the electric field strength is maximized at the center of the opposing surfaces 100a and 100b. As shown in FIG. 2C, the distribution has a mountain shape with a peak at the center. Therefore, a discharge phenomenon is likely to occur in the central region of the opposing surfaces 100a and 100b where the electric field is concentrated. For example, in the case of corona discharge, the discharge phenomenon starts when the electric field value exceeds a certain reference value. When the discharge phenomenon occurs, the propagation of electromagnetic waves is interrupted. Therefore, when the waveguide cavity resonator 100 is applied to the radar apparatus of FIG. 6, the apparatus does not function. For this reason, in the waveguide structure shown in FIG. 2A, it is difficult to further improve the power durability, and it is difficult to improve the radar detection performance.

  On the other hand, the waveguide cavity resonator 1 shown in FIG. 1A is dimensionally the same as FIG. 2A, but is further added with another structure to be described later. That is, the waveguide cavity resonator 1 is formed with a hole 2 as a recess in one side of the opposing surfaces 1a and 1b, in the central region of the opposing surface 1a in FIG. The hole 2 penetrates from the facing surface 1a to the outside. The diameter (vertical cross-sectional shape) of the hole 2 is set to 6 mm in this embodiment. Since the diameter 6 mm of the hole 2 is sufficiently smaller than the wavelength in the tube, the electromagnetic wave in the resonance space hardly leaks outside through the hole 2. The lid 3 is made of metal and has a predetermined shape, for example, a square top plate and a side plate erected on the periphery thereof. The lid 3 is arranged so as to cover the hole 2 from the outside. The shape of the top plate of the lid 3 may be a bottomed cylinder or a bottomed square tube. The size of the lid 3 is sufficiently narrower and lower than the resonance space. From this structure and the diameter of the hole 2, the inner space constituted by the lid 3 is as viewed from the resonance space. It is a blocking area.

  By adopting the hole 2 and the lid 3, as shown in FIGS. 1B and 1C, the electric field distribution in the central portion of the facing portions 1a and 1b is depressed, and the electric field concentration is relaxed. .

  In the embodiment of FIG. 1, the hole 2 penetrating to the outside is formed in the electric field concentration region. However, a structure for reducing current concentration is provided for at least one of the opposing surfaces 1a and 1b in the electric field concentration region. For example, a part of the inner wall (metal part) is removed from at least one of the opposing surfaces 1a and 1b, that is, the area of the region is increased or the current is dispersed with respect to the electric field concentration region. Can be applied.

  Thereby, it is possible to further increase the electric field strength between the outer peripheral portion of the hole 2 and the facing surface 1b to near the peak value shown in FIG. 2C, and to improve the power durability.

  FIG. 3 is a structural view showing a second embodiment of the waveguide circuit element according to the present invention, FIG. 4 is an exploded view thereof, and FIG. 5 is a view showing an electric field strength distribution. The waveguide circuit element 10 includes first and second metal blocks 11 and 12 and a partition plate 13 interposed between the first and second metal blocks.

  The metal block 11 has a rectangular parallelepiped shape and is made of a conductive metal such as aluminum (Al) having a required thickness. In the metal block 11, a concave portion 110 having a predetermined depth dimension determined from the frequency of the electromagnetic wave used is formed on the surface portion facing the metal block 12. The recessed portion 110 has resonance spaces 111 and 112 having predetermined vertical and horizontal dimensions and height dimensions (see FIG. 1A) determined from the frequency of the used electromagnetic wave. In the resonance space 111, a coupling window 113 for joining with the waveguide 14 which is the main line on the input side is formed penetrating in the thickness direction of the block. The coupling window 113 serves as an entrance for electromagnetic waves. The coupling window 114 is formed between the resonance spaces 111 and 112.

  The metal block 12 has a rectangular parallelepiped shape that is the same size as the metal block 11, and is made of a conductive metal such as aluminum (Al). The metal block 12 has a mirror-symmetric structure, that is, a recessed portion 120 having a predetermined depth determined from the frequency of the used electromagnetic wave, on the surface portion facing the metal block 11. The recessed portion 120 has resonance spaces 121 and 122 having predetermined vertical and horizontal dimensions respectively determined from the frequency of the used electromagnetic wave. In the resonance space 121, a coupling window 123 is formed so as to penetrate in the thickness direction of the block for joining with the waveguide 15 which is the main line on the output side. The coupling window 123 serves as an electromagnetic wave outlet. The coupling window 124 is formed between the resonance spaces 121 and 122. Note that the coupling windows 113 and 123 are not limited to the positions shown in FIG. 4, and positions suitable as electromagnetic wave input / output ports can be employed.

  The partition plate 13 is made of, for example, a conductive material made of aluminum (Al), and functions as a cover material for each of the recessed portions 110 and 120 of the metal blocks 11 and 12. In the present embodiment, each waveguide portion constituted by the resonance regions 111, 112, 121, 122 and the partition plate 13 functions as a resonator. The partition plate 13 is formed (perforated) with four coupling windows 131 to 134 having a required shape at required positions. Although not shown in the drawing, a required number of holes for mechanical fastening are formed at positions corresponding to the metal blocks 11 and 12 and the partition plate 13 and where the recessed portions 110 and 120 are removed. For example, the waveguide is formed by tightening with a bolt and a nut with a required pressure.

  The coupling windows 131 to 134 are formed by cutting out appropriate portions of the partition plate 13, and are formed at positions where the fundamental wave is passed between the resonance spaces 112 and 122 while blocking the second harmonic and the like. The additional regions 115 and 116 of the resonance space 112 have a shape in which the E surface of the resonance space 112 partially protrudes, the width along the longitudinal direction of the E surface is equal to or less than a half wavelength of the fundamental wave, and the second harmonic. More than half wavelength. Therefore, the second harmonic electromagnetic field penetrates into these additional regions 115 and 116 and is distributed. The same applies to the additional regions 125 and 126 of the resonance space 122. Therefore, the coupling windows 131 and 132 can be arranged at a position where the electric field energy of the second harmonic mode is high and at a position where the electric field energy of the fundamental wave mode is low. In this way, the waveguide circuit element 10 is composed of a four-stage resonator in which four resonators are coupled in order, and a resonator corresponding to the resonance space 112 and a resonator corresponding to the resonance space 122 are secondary. Harmonic mode coupling and propagation is prevented.

  Further, in the waveguide circuit element 10, holes 135 are formed at appropriate positions of the partition plate 13, and additional regions 117 and 127 are formed at appropriate positions of the resonance spaces 111 and 121. The holes 135 and the additional regions 117 and 127 are employed for improving the power durability performance. This will be described below.

  FIG. 5 shows the electric field intensity distribution when an electromagnetic wave having a fundamental frequency is input from the input-side waveguide 14 before the holes 135 are formed in the partition plate 13. The electric field strength has a maximum value in the resonance space 111. As described with reference to FIG. 1, the peak of the electric field intensity basically occurs in the central portion of the resonance space 111 (that is, unless the influence of interference at the input and output portions is taken into consideration).

On the other hand, as can be seen from FIGS. 3 and 4, the present waveguide circuit element 1 has the coupling window 113 formed at the right end of the resonance space 111, and the peak of the electric field strength in this mode is as shown in FIG. 5. It can be seen that the position is slightly away from the left end side of the coupling window 113. This can be achieved by forming the by cutting the side wall of the right side (cutoff region) addition region 117 of the coupling window 113 of the resonance space 111, slightly offset towards the center of the field distribution of the fundamental wave from the left edge of the coupling window 113 It is a thing. And the hole 135 is formed in the partition plate 13 corresponding to this electric field strength peak position. The hole 135 has a required long shape. As shown in FIG. 5, the shape of the hole 135 is such that the peak region of the electric field intensity is long along the longitudinal direction of the coupling window 113, and this region is included. The hole 135 can be expected to reduce the electric field concentration at the resonance space 121 at the same time. For this reason, an additional region 127 is formed in the resonance space 121 at a mirror-symmetrical position with the resonance space 111 (cut-off region). The hole 135 is formed in a shape and size that block the passage of electromagnetic waves having a fundamental wavelength.

  Each resonance space of the waveguide circuit element 10 has the same size as the resonator according to the first embodiment. In this structure, a discharge experiment was performed before and after the formation of the hole 135. Before the hole 135 was formed, discharge occurred in the resonance space 111 with an electromagnetic wave power of 90 KW. On the other hand, in the state where the hole 135 was formed, it was confirmed that no discharge occurred up to 120 KW.

  The present invention can also employ the following aspects.

(1) In the second embodiment, the holes (recesses) are formed only in the resonance space 111, but holes (recesses) may be appropriately formed in other resonance spaces as necessary. As a shape of a recessed part, a part of spherical surface and a mortar shape are preferable. Moreover, in the aspect of a hole, a circular cross section is preferable.

1A and 1B are diagrams showing a structure of a waveguide circuit element according to a first embodiment of the present invention and electric field distribution characteristics thereof. FIG. 1A is a structural diagram, FIG. 1 (c) is a diagram showing the electric field strength distribution in the II ′ section. FIG. 2 is a comparative example of FIG. 1 and shows a conventional general waveguide cavity resonator. FIG. 2A is a structural diagram, FIG. 2B is an overall electric field distribution diagram, and FIG. It is a figure which shows the electric field strength distribution in a II-II 'cross section. It is a structural diagram showing a second embodiment of a waveguide circuit element according to the present invention. FIG. 4 is an exploded view of FIG. 3. It is a figure which shows the electric field strength distribution in FIG. It is a block diagram which shows the structure of the radar apparatus as an example of the microwave transmitter / receiver to which the waveguide circuit element based on this invention is applied.

1 Waveguide cavity resonator (waveguide circuit element)
1a, 1b Opposing surface 2 hole (concave)
3 Lid 10 Waveguide cavity resonator (waveguide circuit element, waveguide structure)
11,12 Metal block (metal member)
111, 112, 121, 122 Resonance space 113 Coupling window (main coupling window)
117, 127 Cut-off area 13 Partition plate 131-134 Connection window 135 Hole (recess)
14,15 Waveguide (main waveguide)

Claims (5)

In a waveguide circuit element made of a metal member having opposed surfaces parallel to each other separated by a predetermined height inside and formed with a resonance space for resonating an electromagnetic wave having a fundamental wavelength,
A waveguide circuit characterized in that a hole penetrating to the outside of the metal member is provided in one of the opposing surfaces corresponding to an electric field concentration region where the electric field intensity at the fundamental wavelength is maximum in the resonance space. element. Cross-sectional shape of the front Kiana are waveguide circuit device of claim 1, wherein the radiation of the electromagnetic wave of the fundamental wavelength through the pores is set to a dimension that is restricted. The metal member includes first and second metal blocks opposed to each other and a partition plate interposed between the first and second metal blocks, and is opposed to the first and second metal blocks. On the surface side, at least one of the resonance spaces is formed mirror-symmetric with respect to the partition plate, and the partition plate is formed with a coupling window for connecting the resonance spaces formed on both sides, the holes, waveguide circuit device according to claim 1 or 2, characterized in that it is formed in the partition plate. A waveguide structure in which one of the resonance spaces of the waveguide circuit element according to any one of claims 1 to 3 and a main waveguide transmitting the fundamental frequency are connected via a main coupling window. The waveguide structure is characterized in that the hole is formed on one of opposing surfaces forming the one resonance space.   The waveguide structure according to claim 4, wherein a cut-off portion is continuously provided at an appropriate side surface of the one resonance space.