阅读说明：本技术 矩形波导工字形隔离网络双微带转换器 (Rectangular waveguide I-shaped isolation network double-microstrip converter ) 是由 党章 朱海帆 李凯 张能波 胡顺勇 黄建 于 2021-07-31 设计创作，主要内容包括：本发明公开的一种矩形波导工字形隔离网络双微带转换器,传输损耗小,工作频带宽,隔离度高。属于微波器件领域。本发明通过下述技术方案实现：在矩形波导体前后两侧宽边上,以矩形波导腔中心为对称面制出插槽,作为转换器的输出的两组微带线通过上述对称面插槽,分别垂直互联在矩形波导体中的两条互为平行的阻抗调配线上,两个镜像对称的微带探针相连阻抗调配线,伸入到矩形波导腔中,两条阻抗调配线分别通过两组微带线的垂足连通工字形隔离网络,将实现了等幅同相转换的射频信号传输至两组微带线中,从而实现波导与微带的转换。研制结果表明:本发明在13～17GHz频段范围内插入损耗小于0.3dB,相对带宽分别可达30％与27％。(The rectangular waveguide I-shaped isolation network double-microstrip converter disclosed by the invention has the advantages of small transmission loss, wide working frequency band and high isolation degree. Belongs to the field of microwave devices. The invention is realized by the following technical scheme: slots are formed on the front and rear side wide edges of the rectangular waveguide body by taking the center of the rectangular waveguide cavity as a symmetrical plane, two groups of microstrip lines as the output of the converter are respectively and vertically interconnected on two parallel impedance matching lines in the rectangular waveguide body through the slots of the symmetrical plane, two microstrip probes in mirror symmetry are connected with an impedance matching line and extend into the rectangular waveguide cavity, the two impedance matching lines are respectively communicated with an I-shaped isolation network through the vertical feet of the two groups of microstrip lines, and radio-frequency signals realizing equal-amplitude in-phase conversion are transmitted to the two groups of microstrip lines, so that the conversion of the waveguide and the microstrip is realized. Research results show that the insertion loss of the invention is less than 0.3dB in the frequency range of 13-17 GHz, and the relative bandwidth can respectively reach 30% and 27%.)

1. A rectangular waveguide I-shaped isolation network double microstrip converter comprises: the system has the rectangular waveguide body of blind slot, the terminal system as the converter input has the rectangular waveguide cavity (1) of the short-circuit face of waveguide (6), with the help of the slot on the broadside of one side of rectangular waveguide body, insert the medium base plate (7) in the rectangular waveguide cavity (1) in a cantilever manner, characterized by: slots with the center of the rectangular waveguide cavity (1) as a symmetrical plane are formed on the front and rear wide sides of the rectangular waveguide body, two groups of microstrip lines (4) as the output of the converter are respectively and vertically interconnected on two parallel impedance adjusting lines (3) in the rectangular waveguide body (1) through the slots with the symmetrical plane, two microstrip probes (2) which are in mirror symmetry are connected with the impedance adjusting lines (3) and extend into the rectangular waveguide cavity (1), the two impedance adjusting lines (3) are respectively communicated with an I-shaped isolation network (5) through the vertical feet of the two groups of microstrip lines (4), and radio-frequency signals which realize equal-amplitude and same-phase conversion are transmitted to the two groups of microstrip lines (4), so that the conversion between the waveguide and the microstrip is realized.

2. The rectangular waveguide i-shaped isolation network dual microstrip transducer of claim 1 wherein: the impedance characteristic of the two groups of microstrip lines (4) is 50 omega, the center frequency of the microstrip lines is 15GHz-18 GHz, and the width of the microstrip lines is 1.13mm-15 mm.

3. The rectangular waveguide i-shaped isolation network dual microstrip transducer of claim 1 wherein: the center of the same side of the rectangular waveguide (1) and the wide side is a symmetrical plane, and the two microstrip probes (2) which are symmetrically distributed couple radio-frequency signals in the rectangular waveguide.

4. The rectangular waveguide i-shaped isolation network dual microstrip transducer of claim 1 wherein: the two microstrip probes (2) transmit coupled radio-frequency signals to the two microstrip lines (4) by means of symmetrical impedance adjusting lines (3) on a dielectric substrate (7) inserted into the rectangular waveguide (1) to realize double-microstrip constant-amplitude in-phase conversion, so that transition between the rectangular waveguide cavity (1) provided with the waveguide short-circuit surface (6) at the terminal and the double microstrip is realized, and constant-amplitude in-phase conversion is realized.

5. The rectangular waveguide i-shaped isolation network dual microstrip transducer of claim 1 wherein: and the I-shaped isolation network (5) is communicated with the two groups of microstrip lines and is used for improving the isolation between the microstrip lines.

6. The rectangular waveguide i-shaped isolation network dual microstrip transducer of claim 1 wherein: two groups of microstrip lines (4) are connected with the impedance adjusting line (3) and the I-shaped isolation network (5) through symmetrical slots which are arranged in the rectangular waveguide cavity in the front-back direction in an opposite mode.

7. The rectangular waveguide i-shaped isolation network dual microstrip transducer of claim 1 wherein: one end of the probe is extended into the waveguide through the window of the waveguide surface to form a microstrip probe (2) with an open end surface, and the other end of the probe is connected with an impedance adjusting wire (3).

8. The rectangular waveguide i-shaped isolation network dual microstrip transducer of claim 1 wherein: the impedance matching among the microstrip probe (2), the microstrip line (4) and the I-shaped isolation (5) is realized by the impedance adjusting wire (3).

9. The rectangular waveguide i-shaped isolation network dual microstrip transducer of claim 1 wherein: two A ends of the I-shaped isolation network (5) are respectively connected to the intersection points of the two groups of impedance adjusting wires (3) and the 50 omega microstrip lines (4).

10. The rectangular waveguide i-shaped isolation network dual microstrip transducer of claim 1 wherein: mutual coupling signals between two micro-strip probes (2) inserted into the rectangular waveguide cavity (1) are transmitted through an A-A path of the I-shaped isolation network (5), and are in equal amplitude and opposite phase at the A end of the I-shaped isolation network (5) so as to be cancelled; finally, the mutual coupling signal is shunted to the B end through the A-B path of the I-shaped isolation network (5).

Technical Field

The invention belongs to the field of microwave devices, and particularly relates to a high-isolation waveguide microstrip conversion technology applied to the fields of communication, radar, remote sensing, industrial production and the like.

Background

Waveguides and microstrips are very common transmission line forms in existing microwave circuits. Because the transmission of radio frequency signals in the waveguide and the microstrip is completed by the waveguide-microstrip transition device, it is necessary to design a waveguide-microstrip conversion device with wide frequency band and low loss. The specific conversion mode mainly comprises the following three modes: the device comprises a ridge fin conversion structure, a waveguide-coaxial-microstrip line conversion structure and 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 larger; for the third conversion mode, the waveguide and the microstrip are orthogonal to each other, so that the microwave circuit has the advantages of no need of welding, convenience in installation and small occupied space, and becomes a common mode in microwave circuit design. The waveguide microstrip converter is one of the more applied devices in a microwave system, and the main function of the waveguide microstrip converter is to realize the transition of microwave signals between two different transmission lines of a waveguide and a microstrip. In the whole process, the loss and reflection of the microwave signal are required to be as small as possible. The rectangular waveguide has the characteristics of low loss and high power capacity, and the microstrip line is used as a planar circuit and is easy to integrate a semiconductor device, so that the waveguide microstrip converter has the main function of combining the advantages of the two. The waveguide microstrip converter has various circuit forms, such as probe electric field coupling, magnetic ring coupling, ridge waveguide transition and the like. In practical engineering application, a plurality of semiconductor devices are often required to be integrated in a limited space, so that a plurality of microstrip transition circuits which are symmetrically distributed in a rectangular waveguide are required to be designed to realize simultaneous conversion of multiple paths of signals. The multi-path disposable waveguide microstrip converter has the advantages of compact circuit form, small insertion loss and the like, and is widely applied to various microwave systems. However, the converter with the microstrip circuit inserted into the rectangular waveguide lacks an isolation circuit, so that the isolation between the microstrip branches is only 6dB theoretically, and the converter is difficult to be applied to systems with higher requirements (usually more than or equal to 15dB) on the isolation between channels, such as phased array feeder networks, balanced mixing, high-power synthesis and the like.

For the existing rectangular waveguide double-microstrip converter, two microstrip probes 2 symmetrically distributed according to the center of a rectangular waveguide are inserted into the same side and the wide side of the rectangular waveguide, and the probes are parallel to TE transmitted in the rectangular waveguide double-microstrip converter₁₀And the mode electric field lines realize the high-efficiency conversion of signals between the waveguide and the microstrip lines. Meanwhile, two microstrip probes 2 are inserted and are symmetrical, so that microwave signals in the rectangular waveguide are equally divided and transferred into two microstrip lines; in the circuit performance of the rectangular waveguide dual microstrip converter, in addition to the distribution conversion characteristics, it is often necessary to have good isolation between microstrip ports, that is, it is required that microwave signals of two microstrip lines cannot enter each other into the microstrip line of the other microstrip line. However, for the existing rectangular waveguide dual microstrip converter, due to the lack of an isolation device, the two microstrip lines generate mutual coupling of radio frequency signals at the microstrip probe 2 inserted into the rectangular waveguide, so that the purpose of isolation cannot be achieved.

In order to reduce the insertion loss during the transition between the waveguide and the microstrip line, the prior art has taken the measure of inserting a probe parallel to the electric field into the waveguide. In the prior art related to the improvement of isolation, for example, patent application No. 202010380303.6 discloses a method and an apparatus for increasing isolation between radio frequency multiple channels, which aims at the condition that multiple channels are designed on a PCB board, by adding a microstrip resonance structure between radio frequency channels, and using the characteristics of a microstrip resonance cavity, absorb microwave signals leaked between the channels, and reduce the energy of the leaked signals, thereby realizing the effect of improving the isolation between the channels; however, the isolation degree is increased by adopting a physical space isolation mode, only the signal leaked into the space is blocked, the method is not suitable for transmission isolation of the rectangular waveguide double-microstrip transition circuit, and the isolation degree effect is improved to a limited extent.

Disclosure of Invention

In order to solve the technical problems, the invention provides the rectangular waveguide double-microstrip converter which is small in transmission loss, wide in working frequency band and high in isolation degree, and an I-shaped isolation network is inserted between two microstrip lines.

The technical scheme adopted by the invention is as follows: a rectangular waveguide I-shaped isolation network double microstrip converter comprises: the rectangular waveguide with the blind slot is characterized in that a rectangular waveguide body with the blind slot is manufactured, a rectangular waveguide cavity 1 with a waveguide short-circuit surface 6 is manufactured as a terminal of converter input, and a dielectric substrate 7 inserted into the rectangular waveguide cavity 1 in a cantilever mode is inserted into a slot on the wide side of one side of the rectangular waveguide body, and the rectangular waveguide with the slot is characterized in that: slots with the center of the rectangular waveguide cavity 1 as a symmetrical plane are formed on the front and back wide sides of the rectangular waveguide body, two groups of microstrip lines 4 as the output of the converter are respectively and vertically interconnected on two parallel impedance adjusting lines 3 in the rectangular waveguide body 1 through the slots of the symmetrical plane, two microstrip probes 2 in mirror symmetry are connected with the impedance adjusting lines 3 and extend into the rectangular waveguide cavity 1, the two impedance adjusting lines 3 are respectively communicated with an I-shaped isolation network 5 through the vertical feet of the two groups of microstrip lines 4, and radio-frequency signals realizing equal-amplitude and same-phase conversion are transmitted to the two groups of microstrip lines 4, so that the conversion of the waveguide and the microstrip is realized.

The invention has the beneficial effects that:

the invention adopts a rectangular waveguide body with a blind slot as a rectangular waveguide cavity 1 input by a converter, inserts a medium substrate 7 in the rectangular waveguide cavity 1 in a cantilever mode by means of a slot on the wide side of one side of the rectangular waveguide body, and offsets and shunts mutual coupling signals generated by two microstrip lines at a microstrip probe 2 inserted in the rectangular waveguide, thereby realizing the isolation between two microstrip conversion branches. And the isolation network has simple and compact structure, wide frequency band and convenient processing and assembly.

The invention is on the front and back sides of the rectangular waveguide body, there are slots with the center of the rectangular waveguide cavity 1 as the symmetrical plane, two groups of microstrip lines 4 as the output of the converter are connected vertically to the two parallel impedance adjusting lines 3 in the rectangular waveguide body 1 through the slots of the symmetrical plane, two mirror symmetric microstrip probes 2 are connected to the impedance adjusting lines 3, and extend into the rectangular waveguide body 1, the loss is small, the frequency band is wide. Research results show that the insertion loss of the converter is less than 0.3dB in the frequency band range of 13-17 GHz, and the relative bandwidths of the echoes of an input waveguide end and an output microstrip end, which are better than-15 dB, can respectively reach 30% and 27%.

The invention adopts two impedance adjusting wires 3 to be respectively communicated with an I-shaped isolation network 5 through the vertical feet of two groups of microstrip lines 4, and transmits the radio frequency signal which realizes the equal-amplitude and same-phase conversion to the two groups of microstrip lines 4, thereby realizing the conversion between the waveguide and the microstrip; by inserting the I-shaped isolation network between the two microstrip lines, the mutual coupling signals generated by the two microstrip lines at the microstrip probe 2 inserted into the rectangular waveguide are offset and shunted, so that the isolation between the two microstrip lines in the rectangular waveguide double-microstrip converter is realized, and the overall performance index of the rectangular waveguide double-microstrip converter is improved. The development result shows that the relative bandwidth of the isolation between the two microstrip ports is higher than 15dB and is up to 36%.

Drawings

FIG. 1 is a cross-sectional view of a rectangular waveguide I-shaped isolation network dual microstrip transition of the present invention;

FIG. 2 is a sectional view taken along line I-I of FIG. 1;

FIG. 3 is a signal flow diagram of the I-shaped isolation network of FIG. 2;

fig. 4 is a schematic diagram of port echo, port transmission and isolation effect curves of the rectangular waveguide dual microstrip converter of the present invention.

In the figure: the device comprises a rectangular waveguide cavity 1, a microstrip probe 2, an impedance adjusting wire 3, a microstrip line 4, an I-shaped isolation network 5, a waveguide short-circuit surface 6 and a dielectric substrate 7.

The invention is further explained below with reference to the drawings:

Detailed Description

Refer to fig. 1 and 2. In a preferred embodiment described below, a rectangular waveguide i-shaped isolated network dual microstrip transducer comprises: the rectangular waveguide with the blind slot is characterized in that a rectangular waveguide body with the blind slot is manufactured, a rectangular waveguide cavity 1 with a waveguide short-circuit surface 6 is manufactured as a terminal of converter input, and a dielectric substrate 7 inserted into the rectangular waveguide cavity 1 in a cantilever mode is inserted into a slot on the wide side of one side of the rectangular waveguide body, and the rectangular waveguide with the slot is characterized in that: slots with the center of the rectangular waveguide cavity 1 as a symmetrical plane are formed on the front and back wide sides of the rectangular waveguide body, two groups of microstrip lines 4 as the output of the converter are respectively and vertically interconnected on two parallel impedance adjusting lines 3 in the rectangular waveguide body 1 through the slots of the symmetrical plane, two microstrip probes 2 in mirror symmetry are connected with the impedance adjusting lines 3 and extend into the rectangular waveguide cavity 1, the two impedance adjusting lines 3 are respectively communicated with an I-shaped isolation network 5 through the vertical feet of the two groups of microstrip lines 4, and radio-frequency signals realizing equal-amplitude and same-phase conversion are transmitted to the two groups of microstrip lines 4, so that the conversion of the waveguide and the microstrip is realized.

The dielectric substrate is made of Rogers 4350B with a dielectric constant of 3.48-3.6 and a thickness of 0.508-1.2 mm. The thickness of the microstrip line is 0.035 mm. It can be calculated that the width of the two groups of microstrip lines 4 with impedance characteristics of 50 Ω is 1.13mm to 2.94mm when the frequency is 12GHz to 18 GHz.

And two microstrip probes 2 which are symmetrically distributed are arranged to couple radio-frequency signals in the rectangular waveguide 1 by taking the center of the same side of the wide edge as a symmetrical plane. The two microstrip probes 2 transmit coupled radio-frequency signals to the two microstrip lines 4 by means of symmetrical impedance adjusting lines 3 on a dielectric substrate 7 inserted into the rectangular waveguide 1, so that double microstrip equal-amplitude and same-phase conversion is realized, and transition between the rectangular waveguide cavity 1 with a waveguide short-circuit surface 6 at a terminal and the double microstrip is realized; the double microstrip lines 4 of the converter are symmetrical to the rectangular waveguide 1 in structure, so that equal-amplitude and same-phase conversion is realized.

The I-shaped isolation network 5 is communicated with the two groups of microstrip lines and is used for improving the isolation between the microstrip lines, and the two groups of microstrip lines 4 are connected with the impedance adjusting line 3 and the I-shaped isolation network 5 through symmetrical slots which are arranged in the front and back directions of the rectangular waveguide cavity in opposite directions; one end of the probe is extended into the waveguide through a window on the waveguide surface to form a microstrip probe 2 with an open end surface, and the other end of the probe is connected with an impedance adjusting wire 3; impedance matching among the microstrip probe 2, the microstrip line 4 and the I-shaped isolation network 5 is realized by an impedance adjusting line 3; the microstrip line 4 has a standard 50 Ω characteristic impedance in accordance with the test system, and thus serves as an output port.

As shown in fig. 3, two a ends of the i-shaped isolation network 5 are respectively connected to the intersection points of the two impedance tuning wires 3 and the 50 Ω microstrip line 4.

Mutual coupling signals between two micro-strip probes 2 inserted into the rectangular waveguide cavity 1 are transmitted through an A-A path of the I-shaped isolation network 5, and are in equal amplitude and opposite phase at the A end of the I-shaped isolation network 5 so as to be cancelled; finally, the mutual coupling signal is shunted to the B terminal via the a-B path of the i-shaped isolation network 5. Since the mutual coupling signal can not enter the 50 omega microstrip line 4 as the microstrip output port, the isolation between the two microstrip ports of the converter is realized.

The effect of the rectangular waveguide double-microstrip converter with the I-shaped isolation network is shown in fig. 3, the waveguide double-microstrip transition transmission is equal-amplitude and same-phase power distribution, and the relative bandwidth of the double-microstrip interval separation degree higher than 15dB is up to 36%. In addition, the relative bandwidths of the echoes of the input waveguide end and the output microstrip end of the converter, which are better than-15 dB, can reach 30 percent and 27 percent respectively. Obviously, by adopting the converter structure of the invention, the isolation and the port echo can meet the requirements of circuits such as a broadband phased array feeder network, balanced frequency mixing, high-power synthesis and the like.

It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.