A rectangular waveguide-microstrip line transition conversion circuit with a narrow-side planar probe structure

Abstract

The present invention relates to the field of radio frequency microwave circuit technology. A rectangular waveguide-microstrip line transition conversion circuit of a narrow-side planar probe structure is disclosed, comprising: a first rectangular waveguide; a dielectric substrate connected to the cross section of the end of the first rectangular waveguide in the signal transmission direction; a microstrip probe transition conversion structure circuit, comprising a microstrip probe circuit and a grounded metal strip line laid on the surface of the dielectric substrate, the microstrip probe circuit extending into the first rectangular waveguide along the center position of a narrow side of the first rectangular waveguide, and the grounded metal strip line extending into the first rectangular waveguide along the wide side of the first rectangular waveguide. The present invention can realize a waveguide-microstrip transition conversion circuit structure in which a microstrip probe circuit is inserted into the center of the narrow side of the rectangular waveguide, a microstrip line output on the narrow side of the rectangular waveguide in an electrically excited coupling manner, and a narrowband bandwidth characteristic of a certain frequency, so as to meet some design requirements in actual engineering.

Description

Technical Field

[0001] The invention relates to the technical field of radio frequency microwave circuits, and in particular to a rectangular waveguide-microstrip line transition conversion circuit with a narrow-side planar probe structure. Background Art

[0002] Rectangular waveguide and microstrip line are two types of waveguide systems commonly used in microwave and millimeter wave technology. The transition connection between the two has a large number of application requirements in actual engineering design. At present, there are two common ways to transition from rectangular waveguide to microstrip probe. One is that the dielectric substrate surface is perpendicular to the transmission direction of the rectangular waveguide, that is, the dielectric substrate is placed on the cross section of the rectangular waveguide; the other is that the dielectric substrate surface is parallel to the narrow wall of the rectangular waveguide and placed along the transmission direction. In both of these substrate surface settings, the planar microstrip probe made on the substrate is inserted from the center of the wide side of the waveguide. Through the electrical excitation coupling of the microstrip probe, the electromagnetic field mode conversion between the main modes of the rectangular waveguide and the microstrip line is completed, and the transitional transmission of electromagnetic signals between these two different media is realized.

[0003] In actual engineering applications, it is often encountered that when designing circuit devices, there is a need to use a waveguide-microstrip transition structure with the characteristic of outputting from the narrow side of a rectangular waveguide in a microstrip line. At present, there are two main methods for realizing this type of circuit structure by placing a substrate in the cross section of a waveguide. One is to insert the planar ring structure circuit made on the substrate into the rectangular waveguide from the narrow side of the waveguide, and realize it through the magnetic excitation coupling of the microstrip metal ring; the other is similar to the insertion method of the planar microstrip probe from the center of the wide side of the waveguide. It also uses a grounded metal strip line perpendicular to the wide side of the rectangular waveguide at the center position in the rectangular waveguide as a probe, and the electromagnetic signal on the probe converted by the electrical excitation method is connected by a strip line perpendicular to the narrow side of the waveguide and connected to it, and is connected in an asymmetric T-shaped structure in accordance with the position of the center point of the length direction of the probe strip line, so as to provide an output channel for the electromagnetic signal after the probe coupling conversion. These two structural circuits that can realize the output characteristics of narrow waveguide microstrip lines have broadband working characteristics and can realize the transition conversion function between rectangular waveguide and microstrip lines in the full frequency band in some microwave and millimeter wave bands. However, there is currently no waveguide-microstrip transition conversion circuit structure that inserts a planar microstrip probe from the center of the narrow side of the rectangular waveguide, outputs the narrow waveguide microstrip line in the form of electrically excited coupling, and has a certain frequency narrowband bandwidth characteristic, which cannot meet some design requirements in actual engineering. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a rectangular waveguide-microstrip line transition conversion circuit with a narrow-side planar probe structure, which can realize the insertion of a microstrip probe circuit at the center of the narrow side of the rectangular waveguide, the output of the microstrip line on the narrow side of the rectangular waveguide in an electrically excited coupling manner, and a waveguide-microstrip transition conversion circuit structure with certain frequency narrowband bandwidth characteristics to meet some design requirements in actual engineering.

[0005] The present invention provides a rectangular waveguide-microstrip line transition conversion circuit with a narrow-side planar probe structure, comprising:

[0006] a first rectangular waveguide;

[0007] a dielectric substrate connected to a cross section of an end of the first rectangular waveguide in a signal transmission direction;

[0008] A microstrip probe transition structure circuit, comprising a microstrip probe circuit and a grounded metal strip line laid on the surface of the dielectric substrate, wherein the microstrip probe circuit extends into the first rectangular waveguide along the center position of a narrow side of the first rectangular waveguide, and the grounded metal strip line extends into the first rectangular waveguide along the wide side of the first rectangular waveguide;

[0009] The microstrip probe circuit is vertically arranged to the ground metal strip line, and a gap is arranged between an insertion end of the microstrip probe circuit and an insertion end of the ground metal strip line.

[0010] In an optional embodiment, a second rectangular waveguide is further included, wherein the second rectangular waveguide terminal is short-circuited and connected to a surface of the dielectric substrate away from the first rectangular waveguide, and the cross-sectional dimensions of the second rectangular waveguide are the same as those of the first rectangular waveguide.

[0011] In an optional embodiment, a recessed area is provided on the surface of the second rectangular waveguide close to the first rectangular waveguide, the length and width of the recessed area are both larger than the waveguide opening size of the second rectangular waveguide, at least a portion of the dielectric substrate is accommodated in the recessed area, and the surface of the dielectric substrate close to the first rectangular waveguide is flush with the end face of the second rectangular waveguide close to the first rectangular waveguide.

[0012] In an optional embodiment, the dielectric substrate comprises:

[0013] A first bearing portion, accommodated in the recessed area;

[0014] A second bearing portion, disposed outside the second rectangular waveguide and corresponding to a narrow side of the second rectangular waveguide;

[0015] The third bearing portion passes through the narrow side of the second rectangular waveguide and is used to connect the first bearing portion and the second bearing portion.

[0016] In an optional embodiment, the microstrip probe circuit includes:

[0017] A microstrip probe extends from the narrow side of the first rectangular waveguide and is arranged on the first bearing portion;

[0018] An impedance transformation strip line connected to the other end of the microstrip probe and arranged on the second bearing portion and the third bearing portion;

[0019] An output microstrip line is connected to the other end of the impedance transformation strip line and is arranged on the second bearing portion. The characteristic resistance of the output microstrip line is 50Ω.

[0020] In an optional embodiment, the distance between the microstrip probe and the waveguide short-circuit surface of the second rectangular waveguide is one quarter of the waveguide length.

[0021] In an optional embodiment, it also includes a metal strip line arranged on the surface of the first bearing part, the metal strip line is located at the outer edge of the waveguide opening of the second rectangular waveguide, the metal strip line is connected to the metal wall of the first rectangular waveguide, and one terminal of the grounded metal strip line is connected to the metal strip line.

[0022] An optional embodiment further includes a channel structure formed on the metal wall of the narrow side of the first rectangular waveguide, and the channel structure is used for the third bearing part to pass through.

[0023] An optional embodiment further includes a metal shielding cavity arranged above the second bearing part, and the lower surface of the second bearing part is adhered to the bottom surface of the metal shielding cavity.

[0024] In an optional embodiment, a surface of the first bearing portion close to the second rectangular waveguide has no copper cladding layer, and a surface of the second bearing portion and the third bearing portion close to the second rectangular waveguide has a copper cladding layer.

[0025] In an optional embodiment, the dielectric substrate is made of Rogers 5800 with a thickness of 0.254 mm.

[0026] The embodiment of the present application provides a rectangular waveguide-microstrip line transition conversion circuit with a narrow-side planar probe structure, which can insert a microstrip probe circuit at the center of the narrow side of the rectangular waveguide, output the microstrip line on the narrow side of the rectangular waveguide in an electrically excited coupling manner, and have a waveguide-microstrip transition conversion circuit structure with certain frequency narrowband bandwidth characteristics to meet some design requirements in actual engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1The figure shows the schematic diagram of the appearance structure of the microstrip probe transition conversion circuit;

[0028] Figure 2 The figure shows a perspective schematic diagram of the internal structure of the microstrip probe transition conversion circuit;

[0029] Figure 3 The figure shows the circuit schematic diagram of the upper surface of the dielectric substrate of the microstrip probe transition conversion circuit;

[0030] Figure 4 Shown is the simulation result of microstrip probe transition conversion circuit.

[0031] Reference numerals

[0032] 1. First rectangular waveguide; 11. Channel structure; 2. Dielectric substrate; 21. First bearing part; 22. Second bearing part; 23. Third bearing part; 3. Second rectangular waveguide; 31. Short-circuit surface; 4. Microstrip probe circuit; 41. Microstrip probe; 42. Impedance transformation strip line; 43. Output microstrip line; 5. Grounded metal strip line; 6. Metal strip line; 7. Metal shielding cavity. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] At present, the transition conversion circuit between rectangular waveguide and microstrip line mainly includes typical structures such as rectangular waveguide-diaporate fin line-microstrip transition, rectangular waveguide-ridge waveguide-microstrip transition, rectangular waveguide-microstrip probe transition and rectangular waveguide-coaxial probe-microstrip transition. Among them, there are two common ways of waveguide-microstrip probe transition. One is that the dielectric substrate surface is perpendicular to the transmission direction of the waveguide, that is, the dielectric substrate is placed on the cross section of the waveguide; the other is that the dielectric substrate surface is parallel to the narrow wall of the waveguide and placed along the transmission direction. In both of these substrate surface settings, the planar microstrip probe made on the substrate is inserted from the center of the wide side of the waveguide. Through the electrical excitation coupling method of the microstrip probe, the electromagnetic field mode conversion between the main modes of the rectangular waveguide and the microstrip line is completed, and the transition transmission of electromagnetic signals between these two different media is realized.

[0035] In actual engineering applications, when designing circuit devices, it is often necessary to use a waveguide-microstrip transition structure that has the characteristics of outputting from the narrow side of a rectangular waveguide in a microstrip line.

[0036] At present, there are two main methods for realizing this type of circuit structure by placing a substrate in a waveguide cross section. One is to insert a planar ring structure circuit made on a substrate into the waveguide from the narrow side of the waveguide, and realize it through the magnetic excitation coupling of a microstrip metal ring; the other is similar to the method of inserting a planar microstrip probe from the center of the wide side of the waveguide. A grounded metal strip line perpendicular to the wide side of the waveguide is set at the center position of the waveguide as a probe, and the electromagnetic signal on the probe converted by electrical excitation is connected by a strip line perpendicular to the narrow side of the waveguide and connected to it, and is connected in an asymmetric T-shaped structure excluding the center point of the probe strip line in the length direction to provide an output channel for the electromagnetic signal after probe coupling conversion.

[0037] The above two design methods can realize the structural circuit with the output characteristics of rectangular waveguide narrow side microstrip line, both of which have broadband working characteristics and can realize the transition conversion function between rectangular waveguide and microstrip line in the full frequency band in some microwave and millimeter wave bands. However, there is currently no waveguide-microstrip transition conversion circuit structure that inserts a microstrip probe from the center of the narrow side of the rectangular waveguide, outputs the waveguide narrow side microstrip line in the form of electrical excitation coupling, and has a certain frequency narrowband bandwidth characteristic, which cannot meet some design requirements in actual engineering.

[0038] For the above problems, refer to Figure 1 The embodiment of the present invention provides a rectangular waveguide-microstrip line transition conversion circuit of a narrow-side planar probe structure, including a first rectangular waveguide 1, the first rectangular waveguide 1 is used for an electromagnetic wave signal input channel, and a dielectric substrate 2 is connected to the cross section at the end of the signal transmission direction of the first rectangular waveguide 1. The two surfaces of the first rectangular waveguide 1 used for the signal transmission direction are defined as an input surface and an output surface. Among the other four surfaces of the first rectangular waveguide 1 except the input surface and the output surface, the surface with a relatively small area is defined as a narrow side, and the surface with a relatively large area is defined as a wide side. The dielectric substrate 2 is mounted on the cross section at the end of the signal transmission direction of the first rectangular waveguide 1, that is, it is mounted on the output surface of the first rectangular waveguide 1.

[0039] In addition, a microstrip probe transition conversion structure circuit is arranged on the surface of the dielectric substrate 2 close to the first rectangular waveguide 1, including a microstrip probe circuit 4 and a grounded metal strip line 5 laid on the surface of the dielectric substrate 2, the microstrip probe circuit 4 extends into the first rectangular waveguide 1 along the center position of a narrow side of the first rectangular waveguide 1, and the grounded metal strip line 5 extends into the first rectangular waveguide 1 along the wide side of the first rectangular waveguide 1, wherein the microstrip probe circuit 4 and the grounded metal strip line 5 are arranged vertically, and a gap is arranged between the insertion end of the microstrip probe circuit 4 and the insertion end of the grounded metal strip line 5.

[0040] It can be understood that by inserting the microstrip probe circuit 4 into the narrow side of the first rectangular waveguide 1, the microstrip probe circuit 4 completes the circuit conversion between the waveguide and the microstrip line in an electrically excited coupling manner. This transition conversion function is mainly achieved by the combined circuit structure of the microstrip probe circuit 4 and the grounded metal strip line 5 perpendicular to it. According to the electromagnetic field structure of the main mode of the first rectangular waveguide 1, there is only an electric field component perpendicular to the wide side of the first rectangular waveguide 1 in the first rectangular waveguide 1. When a microstrip probe circuit 4 is independently inserted into the first rectangular waveguide 1 from the center position of the narrow side of the first rectangular waveguide 1, since the direction of the microstrip probe circuit 4 is perpendicular to the direction of the electric field in the first rectangular waveguide 1, no excitation will be generated on the microstrip probe circuit 4 and no coupling output of signal power will occur. However, after a grounded metal strip line 5 perpendicular to and separated from the microstrip probe circuit 4 is set next to the microstrip probe circuit 4, the field structure of the electromagnetic field in the area between the two will be distorted to a certain extent, resulting in an electric field component with a certain intensity in a direction parallel to the wide side of the first rectangular waveguide 1. By using this electric field component, the transition conversion between the waveguide and the microstrip line can be achieved by inserting the microstrip probe circuit 4 from the narrow side of the first rectangular waveguide 1.

[0041] It also includes a second rectangular waveguide 3, the second rectangular waveguide 3 has a short-circuited terminal and is connected to the surface of the dielectric substrate 2 away from the first rectangular waveguide 1, and the cross-sectional dimension of the second rectangular waveguide 3 is the same as the cross-sectional dimension of the first rectangular waveguide 1. The end surface of the second rectangular waveguide 3 away from the first rectangular waveguide 1 is a short-circuit surface 31, and the waveguide port of the first rectangular waveguide 1 and the waveguide port of the second rectangular waveguide 3 equipped with the dielectric substrate 2 are precisely connected and tightly connected together.

[0042] A recessed area is provided on the surface of the second rectangular waveguide 3 close to the first rectangular waveguide 1, and the length and width of the recessed area are both larger than the waveguide opening size of the second rectangular waveguide 3, at least a portion of the dielectric substrate 2 is accommodated in the recessed area, and the surface of the dielectric substrate 2 close to the first rectangular waveguide 1 is flush with the end face of the second rectangular waveguide 3 close to the first rectangular waveguide 1.

[0043] Specifically, a recessed area is provided symmetrically with respect to the central axis of the second rectangular waveguide 3 , the length and width of which are both 1 mm larger than the waveguide opening size of the second rectangular waveguide 3 and the depth of which is equal to the thickness of the dielectric substrate 2 , so as to accommodate a part of the structure of the dielectric substrate 2 .

[0044] The dielectric substrate 2 includes a first bearing portion 21, which is accommodated in the recessed area; a second bearing portion 22, which is arranged outside the second rectangular waveguide 3 and corresponds to the narrow side of the second rectangular waveguide 3; and a third bearing portion 23, which passes through the narrow side of the second rectangular waveguide 3 and is used to connect the first bearing portion 21 and the second bearing portion 22. The dielectric substrate is a plate-shaped structure, which includes the first bearing portion 21, the second bearing portion 22 and the third bearing portion 23. The first bearing portion 21 is rectangular in shape and is arranged in the waveguide inner area (i.e., the recessed area) of the second rectangular waveguide 3. The perimeter lengths of the first bearing portion 21 extend 0.48 mm to both sides symmetrically with the central axis of the wide and narrow sides of the waveguide opening of the second rectangular waveguide 3. The second bearing portion 22 is arranged in the outer area of ​​one narrow side of the second rectangular waveguide 3. The third bearing portion 23 is arranged in the channel on the metal wall on the narrow side of the second rectangular waveguide 3. The two ends of the third bearing portion 23 are respectively connected to the first bearing portion 21 and the second bearing portion 22.

[0045] The microstrip probe circuit 4 includes: a microstrip probe 41, which extends from the narrow side of the first rectangular waveguide 1 and is arranged on the first bearing portion 21; an impedance transformation strip line 42, which is connected to the other end of the microstrip probe 41 and is arranged on the second bearing portion 22 and the third bearing portion 23; an output microstrip line 43, which is connected to the other end of the impedance transformation strip line 42 and is arranged on the second bearing portion 22, and the characteristic resistance of the output microstrip line 43 is 50Ω.

[0046] Among them, the geometric dimensions and relative positions of the microstrip probe circuit 4 and the grounded metal strip line 5 are related to the performance indicators such as the operating frequency bandwidth and transmission loss of the transition conversion circuit. By changing the geometric dimensions and relative positions of the microstrip probe 41 and the grounded metal strip line 5 on the first bearing part 21, the transition conversion circuit function with a certain bandwidth in different frequency bands can be realized in some microwave and millimeter wave bands.

[0047] Furthermore, the circuit structure of the present application is different from the traditional circuit structure with broadband characteristics in that its own structural characteristics determine that it can only achieve a certain narrowband frequency operating bandwidth. By utilizing this characteristic, in actual engineering design, it can directly meet the demand for the use of a transition conversion circuit that requires the installation of a filter after a conventional broadband transition conversion circuit to achieve narrowband working performance.

[0048] The distance between the microstrip probe 41 and the waveguide short-circuit surface 31 of the second rectangular waveguide 3 is one quarter of the waveguide length.

[0049] It also includes a metal strip line 6 arranged on the surface of the first bearing part 21, the metal strip line 6 is located at the outer edge of the waveguide opening of the second rectangular waveguide 3, the metal strip line 6 is connected to the metal wall of the first rectangular waveguide 1, and one terminal of the grounded metal strip line 5 is connected to the metal strip line 6.

[0050] Among them, the metal strip line 6 is a frame-type structure, which is arranged around the outer edge of the waveguide opening of the second rectangular waveguide 3 and is correspondingly connected to the metal wall of the first rectangular waveguide 1. A gap is provided on the frame-type structure formed by the metal strip line 6 for the microstrip probe 41 to pass through. The grounding is extended from the grounding metal strip line 5 to the part of the metal strip line 6 outside the first rectangular waveguide 1, and is achieved by connecting to the metal wall of the first rectangular waveguide 1.

[0051] It also includes a channel structure 11 formed on the narrow side metal wall of the first rectangular waveguide 1, and the channel structure 11 is used for the third bearing part 23 to pass through, so as to connect the first bearing part 21 with the second bearing part 22 while ensuring that the microstrip probe circuit 4 extends out of the first rectangular waveguide 1.

[0052] The second bearing portion 22 further includes a metal shielding cavity 7 disposed above the second bearing portion 22 , and the lower surface of the second bearing portion 22 is adhered to the bottom surface of the metal shielding cavity 7 .

[0053] The surface of the first bearing portion 21 close to the second rectangular waveguide 3 has no copper cladding layer, and the surfaces of the second bearing portion 22 and the third bearing portion 23 close to the second rectangular waveguide 3 have copper cladding layers.

[0054] The dielectric substrate 2 is made of Rogers 5800 and has a thickness of 0.254 mm.

[0055] A specific embodiment of the present invention is a rectangular waveguide-microstrip line transition conversion circuit with a narrow-side planar probe structure in the Ka band, referring to Figure 1-Figure 3 As shown, the dielectric substrate 2 used is made of Rogers5880 with a thickness of 0.254mm; the microstrip probe 41 inserted into the narrow side of the first rectangular waveguide 1 has a length of 1.305mm and a width of 0.367mm; the length of the grounded metal strip line 5 is 1.197mm and a width of 0.562mm; the distance between the end face of the microstrip probe 41 and the center position of the wide side of the grounded metal strip line 5 is 0.665mm.

[0056] Reference Figure 4 , which is the simulation result of the rectangular waveguide-microstrip line transition conversion circuit of the Ka-band narrow-edge planar probe structure of this embodiment. It can be seen from the figure that within the 500MHz frequency bandwidth range of 37.80-38.32GHz, the insertion loss is less than 0.1dB, and the input return loss is greater than 15.6dB; within the 1.1GHz frequency bandwidth range of 37.52-38.67GHz, the insertion loss is less than 0.5dB, and the input return loss is greater than 9.60dB; within the 1.6GHz frequency bandwidth range of 37.31-38.93GHz, the insertion loss is less than 1dB, and the input return loss is greater than 6.83dB. It can be seen that the waveguide-microstrip line transition conversion circuit has good input impedance matching and good transmission coefficient within a narrow frequency range.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A rectangular waveguide-microstrip line transition conversion circuit with a narrow-side planar probe structure, characterized in that: include: A first rectangular waveguide (1); A dielectric substrate (2) connected to a cross section at an end of the first rectangular waveguide (1) in a signal transmission direction; A microstrip probe transition structure circuit, comprising a microstrip probe circuit (4) and a grounding metal strip line (5) laid on the surface of the dielectric substrate (2), wherein the microstrip probe circuit (4) extends into the first rectangular waveguide (1) along the center position of a narrow side of the first rectangular waveguide (1), and the grounding metal strip line (5) extends into the first rectangular waveguide (1) along the wide side of the first rectangular waveguide (1); The microstrip probe circuit (4) is arranged perpendicularly to the grounding metal strip line (5), and a gap is provided between an insertion end of the microstrip probe circuit (4) and an insertion end of the grounding metal strip line (5); A second rectangular waveguide (3), the second rectangular waveguide (3) having a short-circuited terminal and connected to a surface of the dielectric substrate (2) away from the first rectangular waveguide (1); A metal strip line (6), the metal strip line (6) being located at the outer edge of the waveguide opening of the second rectangular waveguide (3), the metal strip line (6) being connected to the metal wall of the first rectangular waveguide (1), and one terminal of the grounded metal strip line (5) being connected to the metal strip line (6).

2. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 1, characterized in that: The cross-sectional dimensions of the second rectangular waveguide (3) are the same as the cross-sectional dimensions of the first rectangular waveguide (1).

3. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 2, characterized in that: A recessed area is provided on the surface of the second rectangular waveguide (3) close to the first rectangular waveguide (1); the length and width of the recessed area are both larger than the waveguide opening size of the second rectangular waveguide (3); at least part of the dielectric substrate (2) is accommodated in the recessed area; and the surface of the dielectric substrate (2) close to the first rectangular waveguide (1) is flush with the end face of the second rectangular waveguide (3) close to the first rectangular waveguide (1).

4. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 3, characterized in that: The dielectric substrate (2) comprises: A first bearing portion (21), accommodated in the recessed area; A second bearing portion (22) is arranged outside the second rectangular waveguide (3) and corresponds to a narrow side of the second rectangular waveguide (3); A third bearing portion (23) passes through the narrow side of the second rectangular waveguide (3) and is used to connect the first bearing portion (21) and the second bearing portion (22).

5. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 4, characterized in that: The microstrip probe circuit (4) comprises: A microstrip probe (41) extends from a narrow side of the first rectangular waveguide (1) and is arranged on the first bearing portion (21); An impedance transformation strip line (42) connected to the other end of the microstrip probe (41) and arranged on the second bearing portion (22) and the third bearing portion (23); An output microstrip line (43) is connected to the other end of the impedance transformation strip line (42) and is arranged on the second bearing portion (22); the characteristic resistance of the output microstrip line (43) is 50Ω.

6. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 5, characterized in that: The distance between the microstrip probe (41) and the waveguide short-circuit surface (31) of the second rectangular waveguide (3) is one quarter of the waveguide length.

7. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 4, characterized in that: The metal strip line (6) is arranged on the surface of the first bearing portion (21).

8. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 4, characterized in that: It also comprises a channel structure (11) formed on the metal wall of the narrow side of the first rectangular waveguide (1), wherein the channel structure (11) is used for allowing the third bearing portion (23) to pass through.

9. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 4, characterized in that: It also comprises a metal shielding cavity (7) arranged above the second bearing portion (22), the lower surface of the second bearing portion (22) being adhered to the bottom surface of the metal shielding cavity (7).

10. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 4, characterized in that: The surface of the first bearing portion (21) close to the second rectangular waveguide (3) has no copper cladding layer, and the surfaces of the second bearing portion (22) and the third bearing portion (23) close to the second rectangular waveguide (3) have copper cladding layers.

11. The rectangular waveguide-microstrip line transition conversion circuit of the narrow-side planar probe structure according to claim 1, characterized in that: The dielectric substrate (2) is made of Rogers 5800 and has a thickness of 0.254 mm.

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