CN114188686B

CN114188686B - H-face waveguide/microstrip probe conversion device

Info

Publication number: CN114188686B
Application number: CN202111278164.7A
Authority: CN
Inventors: 裴乃昌; 黄建; 熊阳
Original assignee: Southwest Electronic Technology Institute No 10 Institute of Cetc
Current assignee: Southwest Electronic Technology Institute No 10 Institute of Cetc
Priority date: 2021-10-30
Filing date: 2021-10-30
Publication date: 2023-03-31
Anticipated expiration: 2041-10-30
Also published as: CN114188686A

Abstract

The H-plane waveguide/microstrip probe conversion device provided by the invention has the advantages of low transmission loss, small insertion loss and wide frequency band. The invention is realized by the following technical scheme: the micro-strip probe is connected with the impedance matching branch and extends to two sides to be bent linearly by taking the impedance matching branch as a central fulcrum to form a G-shaped ring open-circuit probe with a right-angle bent opening and form a coupling structure with a waveguide short-circuit surface at the tail end of the rectangular waveguide cavity; when an electromagnetic field signal is input into the waveguide circuit from the waveguide end, the electromagnetic field signal is subjected to electric field coupling with the branch of the microstrip probe at the installation position of the microstrip probe, the uncoupled electromagnetic field signal is subjected to total reflection on the waveguide short-circuit surface and reflected back to the installation surface of the microstrip probe to generate electric field coupling again, the coupled surface currents are superposed in phase, subjected to impedance transformation through the impedance matching branch and then input into the microstrip transmission line and output at the port of the microstrip circuit of the microstrip probe. Thereby completing the transition from the TE10 mode propagated by the waveguide circuit to the quasi-TEM mode propagated by the microstrip circuit.

Description

H-face waveguide/microstrip probe conversion device

Technical Field

The invention relates to an H-plane waveguide/microstrip probe conversion device mainly applied to circuit conversion between a waveguide and a microstrip transmission line.

Background

With the wide application of millimeter wave technology in modern wireless communication systems, the demand for various high-performance millimeter wave integrated circuits is increasing. The microstrip line is an important transmission line form in the existing millimeter wave integrated circuit, and the waveguide-microstrip conversion structure for MMIC monolithic packaging test of each millimeter wave monolithic microwave integrated circuit is mainly connected by the microstrip line. With the continuous research and development in the high-frequency band field, microstrip lines have not been able to meet the requirement for low transmission loss. The transmission of radio frequency signals in waveguides and microstrips must be accomplished by waveguide-microstrip transition devices. Therefore, it is necessary to design a broadband and low-loss waveguide-microstrip conversion device, and the specific conversion mode mainly includes the following three forms: a ridge-fin conversion structure; a waveguide-coaxial-microstrip line conversion structure; a waveguide-microstrip probe conversion structure. For the former two conversion modes, the waveguide and the microstrip are in the same direction, and the occupied space is large; for the third conversion mode, the waveguide and the microstrip are orthogonal to each other, so that the method has the advantages of no need of welding, convenience in installation and small occupied space, and becomes a common mode in MMIC circuit design. The waveguide microstrip probe circuit is designed as a key circuit of a millimeter wave and terahertz receiving and transmitting front end, and is widely applied to millimeter wave and terahertz receiving and transmitting systems of various working platforms. The waveguide microstrip probe is mainly used for converting signal transmission from a waveguide transmission circuit to a microstrip transmission circuit. The wave band microstrip conversion circuit can be divided into an E-plane waveguide microstrip probe and an H-plane waveguide microstrip probe according to the position where the wave band microstrip conversion circuit probes. The probe of the waveguide-microstrip converter in the E-plane probe mode penetrates into the waveguide through a window on the waveguide surface, the window size is favorable for assembly and is small as much as possible, the influence on the transmission performance of the waveguide can be reduced, and the formed waveguide cut-off frequency is beyond the working frequency. The E-plane waveguide microstrip probe is a circuit most commonly used in waveguide microstrip probes because of simple design and low implementation difficulty. Compared with an E-plane waveguide micro-strip probe, the E-plane waveguide micro-strip probe carries out electromagnetic field coupling on the wide side of the waveguide, and an H-plane waveguide probe carries out electromagnetic field coupling on the narrow side of the waveguide, so that the miniaturized compact layout of a circuit is facilitated, and the E-plane waveguide micro-strip probe has wide application requirements in multichannel transceiving concentration. However, because of the design difficulty of the H-plane waveguide probe, the current reported circuit form is not easy to assemble, and the application of the H-plane waveguide probe is less.

The only H-plane waveguide microstrip probe reported at present adopts a waveguide probe circuit with one U-shaped end grounded to a waveguide wall, and a grounding frame of a dielectric substrate is required to be designed on the mounting surface of the microstrip probe because the probe circuit needs to be grounded. Its performance deteriorates directly with increasing operating frequency. Particularly in the terahertz frequency band, a microstrip circuit is mostly processed and realized by adopting a quartz substrate, the quartz substrate is very fragile and cannot be processed with a metalized through hole, and a quartz medium substrate cannot be processed to realize a grounding frame.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the H-plane waveguide/microstrip probe conversion device which has the advantages of simple structure, low transmission loss, small insertion loss, small reflection of a wide frequency band port, wide frequency band and easy integration.

The invention is realized by the following technical scheme: an H-plane waveguide/microstrip probe conversion device, comprising: the waveguide micro-strip probe is characterized in that the short side of the waveguide is parallel to a dielectric substrate 2 inserted into the H surface of a rectangular waveguide cavity, the waveguide micro-strip probe 1 printed on the upper surface of the dielectric substrate 2 is orthogonal to an air constraint cavity 9 on a rectangular waveguide 7, and the waveguide micro-strip probe is characterized in that: the medium substrate 2 extends into the rectangular waveguide 7 from the narrow side H surface of the rectangular waveguide 7 through the air constraint cavity 9, the waveguide microstrip probe 1 is connected with the impedance matching branch 4 through a section of microstrip transmission line 3 and expands and bends linearly towards two sides by taking the impedance matching branch 4 as a central fulcrum, the top of the G-shaped ring open-circuit probe 6,G ring open-circuit probe 6 which forms a right-angle bending opening is positioned in the center of the waveguide and is parallel to the direction of an electric field, and a coupling structure is formed by the G-shaped ring open-circuit probe and the rectangular waveguide cavity tail end waveguide short-circuit surface 8; electromagnetic field signals are input into the waveguide circuit 7 from the waveguide end, the electromagnetic field signals are in electric field coupling with the

branches

5 and 6 of the microstrip probe at the installation position of the microstrip probe, the uncoupled electromagnetic field signals are in total reflection on the waveguide short-circuit surface 8 and are reflected back to the installation surface of the microstrip probe, and the electromagnetic field coupling with the

branches

5 and 6 is achieved again, and the conversion efficiency is improved. The coupled surface currents of the branch 5 and the branch 6 are superposed in phase, subjected to impedance transformation by the impedance matching branch 4, input to the microstrip transmission line 3 and output at a microstrip circuit port of the microstrip probe 1. Thereby completing the transition from the waveguide circuit to the microstrip circuit.

Compared with the prior art, the invention has the following beneficial effects.

Has wide band and low transmission loss. The invention adopts a dielectric substrate 2 which is parallel to the H surface of the inserted rectangular waveguide cavity from the short side of the waveguide, a waveguide micro-strip probe 1 which is printed on the upper surface of the dielectric substrate 2, and an H surface waveguide/micro-strip probe conversion device which is formed by an air constraint cavity 9 which is vertical to the rectangular waveguide 7, and integrates a probe circuit conductor on a rectangular dielectric substrate. The transmission loss is low, and the field excitation mode by directly inserting the microstrip probe into the waveguide can ensure that the whole structure is simpler and more compact, and has the advantages of no need of welding, convenience in installation and the like. Compared with the existing H-surface wave waveguide probe circuit, the H-surface electric field coupling probe circuit adopting electric field coupling has the advantages that the probe does not need to be grounded, namely, a grounding frame does not need to be designed, and the grounding frame does not cause additional electromagnetic leakage.

According to the invention, a dielectric substrate 2 is adopted to extend into a rectangular waveguide 7 from a narrow side H surface of the rectangular waveguide 7 through an air constraint cavity 9, a waveguide micro-strip probe 1 is connected with an impedance matching branch 4 through a section of micro-strip transmission line 3, and is extended to be bent linearly towards two sides by taking the impedance matching branch 4 as a central fulcrum, so that a G-shaped open-loop probe 6 with a right-angle bent opening is formed, electric field coupling is carried out by utilizing the H surface of the G-shaped open-loop probe 6, the frequency expansibility is good, and the working frequency and the bandwidth can be realized by adjusting the length and the width of the G-shaped open-loop probe 6 and the L-shaped hook probe branch 5 and adjusting the distance of a short-circuit surface. The working bandwidth of the simulation calculation result is 197-228 GHz, the in-band loss is less than 0.1dB, and the port reflection is less than-20 dB.

The invention adopts the technical scheme that the coupling end of the L-shaped hook probe branch 5 generates electric field coupling and is superposed with the coupled surface current in phase, when high-frequency current passes through the G-shaped ring open-circuit probe 6, alternating current generates an alternating magnetic field for exciting electromagnetic waves in the G-shaped ring open-circuit probe 6, and an uncoupled electromagnetic field signal generates total reflection on the waveguide short-circuit surface 8 and is reflected back to the installation position of the microstrip probe for recoupling so as to improve the conversion efficiency. Experiments prove that the transition structure has the advantages of simple structure, small insertion loss, wide frequency band, convenience in processing and the like. A technical solution for circuit conversion from a rectangular waveguide TE10 mode to a microstrip transmission line quasi-TEM mode applicable to various frequency bands is provided for the design of an H-plane waveguide microstrip probe circuit.

The invention is suitable for a circuit design scheme for realizing the interconversion between the waveguide circuit and the microstrip circuit from the H surface of the narrow edge of the waveguide.

Drawings

FIG. 1 is a perspective view of an HFSS simulation model of an H-plane waveguide/microstrip probe conversion apparatus according to the present invention;

FIG. 2 is a side view of FIG. 1;

FIG. 3 is a top view of the FIG. 1H-plane waveguide microstrip probe;

FIG. 4 is a graphical illustration of the results of the HFSS simulation of FIG. 1;

in the figure: the probe comprises a waveguide microstrip probe 1, a dielectric substrate 2, a microstrip transmission line 3, an impedance matching branch 4, a hook probe branch 5L, an open-circuit probe 6G, a rectangular waveguide 7, a waveguide short-circuit surface 8 and an air confinement cavity 9.

The invention will be further explained with reference to the drawings.

Detailed Description

See fig. 1-3. In an exemplary preferred embodiment described below, an H-plane waveguide/microstrip probe transition apparatus includes: the waveguide micro-strip probe is characterized in that the short side of the waveguide is parallel to a dielectric substrate 2 inserted into the H surface of a rectangular waveguide cavity, the waveguide micro-strip probe 1 printed on the upper surface of the dielectric substrate 2 is orthogonal to an air constraint cavity 9 on a rectangular waveguide 7, and the waveguide micro-strip probe is characterized in that: the medium substrate 2 extends into the rectangular waveguide 7 from the narrow side H surface of the rectangular waveguide 7 through the air constraint cavity 9, the waveguide microstrip probe 1 is connected with the impedance matching branch 4 through a section of microstrip transmission line 3 and expands and bends linearly towards two sides by taking the impedance matching branch 4 as a central fulcrum, the top of the G-shaped ring open-circuit probe 6,G ring open-circuit probe 6 which forms a right-angle bending opening is positioned in the center of the waveguide and is parallel to the direction of an electric field, and a coupling structure is formed by the G-shaped ring open-circuit probe and the rectangular waveguide cavity tail end waveguide short-circuit surface 8; electromagnetic field signals are input into the waveguide circuit 7 from the waveguide end, the electromagnetic field signals are in electric field coupling with the

branches

In an alternative embodiment, a G-shaped microstrip probe extends into the waveguide circuit from the narrow side of the waveguide, and two U-shaped branches with the length difference of about half wavelength extend out along the edge of the waveguide, and the two U-shaped branches are opposite in opening at the central line of the narrow side of the waveguide.

The long U-shaped branch is bent at the center of the wide side of the waveguide, the length in the direction parallel to the electric field is about half of the narrow side of the waveguide, and the length in the direction parallel to the electric field in the short U-shaped branch is about half of the narrow side of the waveguide.

The size of the waveguide adopts WR4 standard waveguide, the dielectric substrate is made of quartz material with dielectric constant of 3.78-4.0, the thickness of the dielectric substrate is 0.5mm-1.0, and the thickness of the microstrip line is 0.005mm-0.01mm.

The width of the 50 omega microstrip line at the center frequency of 212.5GHz is calculated to be about 0.1mm by utilizing electromagnetic simulation software, the length and the width of the matching branch 4 are 0.04mm multiplied by 0.14mm, the widths of the

branches

5 and 6 are 0.065mm, the length and the width are 0.41mm and 0.68mm respectively, and the length of the short-circuit surface of the wave band is 0.715 mm. The center frequency of the waveguide microstrip probe is 212.5GHz, the bandwidth is 31GHz, the in-band loss is less than 0.1dB, and the port reflection is less than-20 dB.

See fig. 4. The working frequency is determined by the length difference of the G-shaped open-loop probe 6 and the L-shaped hook probe branch 5 and the distance between the waveguide short-circuit surface 8 and the probe installation surface. The length difference is approximately half the wavelength of the center frequency.

The waveguide microstrip probe circuit has two transmission poles, one is determined by the length difference between the G-shaped open-loop probe 6 and the L-shaped hook probe branch 5, and the other is determined by the distance between the waveguide short-circuit surface 8 and the probe installation surface. The working bandwidth can be adjusted by adjusting the relevant parameters.

The port standing wave of the rectangular waveguide 7 is determined by the length and width of the impedance matching stub 4, and the in-band standing wave can be optimized by adjusting the length and width of the impedance matching stub 4. It can be seen from fig. 4 that within the bandwidth of 197-228 GHz, the port reflection parameter is less than-20 dB, the in-band loss is less than 0.1dB, and the technical requirements are completely met.

The present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and such modifications and improvements are also considered to be within the scope of the present invention. Those not described in detail in this specification are within the skill of the art.

Claims

1. An H-plane waveguide/microstrip probe conversion device, comprising: the waveguide micro-strip probe is characterized in that the probe is a dielectric substrate (2) with a waveguide short side parallel to an H surface of an inserted rectangular waveguide cavity, a waveguide micro-strip probe (1) printed on the upper surface of the dielectric substrate (2) and an air constraint cavity (9) orthogonal to the rectangular waveguide (7), and the probe is characterized in that: the medium substrate (2) extends into the rectangular waveguide (7) from the narrow side H surface of the rectangular waveguide (7) through an air constraint cavity (9), the waveguide microstrip probe (1) is connected with the impedance matching branch (4) through a section of microstrip transmission line (3) and expands to be linearly bent towards two sides by taking the impedance matching branch (4) as a central fulcrum to form a G-shaped ring open-circuit probe (6) with a right-angle bent opening, the G-shaped ring open-circuit probe (6) consists of two U-shaped branches with the length difference of half wavelength, one ends of the two U-shaped branches are connected, the top of the G-shaped ring open-circuit probe (6) is positioned in the center of the waveguide, is parallel to the direction of an electric field and forms a coupling structure with a waveguide short-circuit surface (8) at the tail end of the rectangular waveguide cavity; electromagnetic field signals are input into a rectangular waveguide (7) from a waveguide end, the electromagnetic field signals are in electric field coupling with a G-shaped ring open-circuit probe (6) at the installation position of a waveguide micro-strip probe, the uncoupled electromagnetic field signals are in total reflection at a waveguide short-circuit surface (8) and are reflected back to the installation surface of the waveguide micro-strip probe, the electromagnetic field coupling is generated with the G-shaped ring open-circuit probe (6) again, coupled surface currents are superposed in phase, are input into a micro-strip transmission line (3) after being subjected to impedance transformation through an impedance matching branch (4), and are output at a micro-strip circuit port of the waveguide micro-strip probe (1), so that the transition conversion from a TE10 mode transmitted by the rectangular waveguide to a quasi-TEM mode transmitted by the micro-strip circuit is completed.

2. The H-plane waveguide/microstrip probe transition device of claim 1 wherein: the long U-shaped branch is bent at the center of the wide side of the waveguide, and the length parallel to the electric field direction is half of the narrow side of the waveguide.

3. The H-plane waveguide/microstrip probe transition device of claim 1 wherein: the length of the short U-shaped branch in the direction parallel to the electric field is half of the narrow side of the waveguide.

4. The H-plane waveguide/microstrip probe transition device according to claim 1, characterized in that: the width of a 50 ohm microstrip line of a quartz substrate with the thickness of 0.05mm is 0.1mm, the length and the width of an impedance matching branch (4) are 0.04mm multiplied by 0.14mm, the width of a G-shaped ring open-circuit probe (6) is 0.065mm, the lengths of two U-shaped branches are 0.41mm and 0.68mm respectively, when the length of a waveguide short-circuit surface is 0.715mm, the central frequency of the waveguide microstrip probe is 212.5GHz, the bandwidth is 31GHz, the in-band loss is less than 0.1dB, and the port reflection is less than-20 dB.

5. The H-plane waveguide/microstrip probe transition device of claim 1 wherein: the waveguide microstrip probe circuit has two transmission poles, one is determined by the length difference of two U-shaped branches of the G-shaped ring open-circuit probe (6), the other is determined by the distance between the waveguide short-circuit surface (8) and the probe mounting surface, and the working bandwidth and the in-band standing wave can be adjusted by adjusting the two transmission poles.

6. The H-plane waveguide/microstrip probe transition device of claim 1 wherein: the port standing wave of the rectangular waveguide (7) is determined by the length and the width of the impedance matching branch (4), and the in-band standing wave is optimized by adjusting the length and the width of the impedance matching branch (4).