Microwave transmission structure with radio frequency coaxial load

Abstract

The application provides a microwave transmission mechanism with a radio frequency coaxial load; comprising a radio frequency input end, a plurality of radio frequency output ends, a plurality of load connectors and a plurality of reed assemblies; the lower end of the first push rod of the reed assembly is fixedly connected with the first microwave reed, the upper end of the first push rod extends to the cavity of the shell, and the first spring is sleeved on the first push rod; the lower end of the second push rod is fixedly connected with the second microwave reed, the upper end of the second push rod extends to the cavity of the shell, and the second spring is sleeved on the second push rod; the microstrip section of the load coaxial connector is fixedly welded with the load inner conductor, the load insulator is sleeved on the outer side of the load inner conductor, and the load inner conductor is fixed in the load outer conductor through the load insulator; the center inner conductor of the radio frequency input end, the center inner conductor of the radio frequency output end and the inner conductor of the load connector all extend into the microwave cavity of the base. The problems of signal leakage, mutual interference and damage to the radio frequency source in the use process of the high-frequency multi-channel coaxial switch are solved.

Description

Technical Field

[0001] This invention relates to a microwave transmission mechanism, and more particularly to a microwave transmission mechanism with a radio frequency coaxial load. Background Technology

[0002] A radio frequency coaxial switch is a passive device that uses a coaxial connector as the radio frequency output terminal to switch / select microwave signal channels on demand and achieve high-quality signal transmission. It is an indispensable basic component in multi-channel microwave systems and has advantages such as low VSWR, low insertion loss, wide bandwidth, and high power tolerance.

[0003] With the development of electronic warfare technology and the upgrading of military equipment, ordinary coaxial switches can no longer meet the reliability requirements of system equipment, and the demand for high-frequency, high-power, multi-channel coaxial switches is increasing. Multiple coaxial switches are combined into a switch matrix system for microwave signal routing, with the switches connected to the output terminals of the signal source, and multiple functional load devices connected to their output terminals. Because the switch matrix has many output paths, any idle open-circuit transmission line may resonate within the microwave frequency range. This resonance may reflect electrical energy back to the operating radio frequency source, causing damage. For high-frequency, high-power systems, the damage will be even more severe due to the significantly reduced isolation. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a microwave transmission mechanism with radio frequency coaxial load that improves the reliability of high-frequency, high-power microwave electronic countermeasures systems.

[0005] To solve the above-mentioned technical problems, the present invention provides a microwave transmission mechanism with a radio frequency coaxial load;

[0006] It includes an RF input terminal, several RF output terminals, several load connectors, and several spring assemblies;

[0007] The RF input terminal, several RF output terminals, and several load connectors are all fixed on the outside of the coaxial switch base, and the coaxial switch base is equipped with a microwave cavity.

[0008] A number of RF output terminals, a number of load connectors, and a number of reed assemblies correspond one-to-one. The reed assembly includes a first microwave reed, a second microwave reed, a first spring, a first push rod, a second spring, and a second push rod. The first microwave reed and the second microwave reed are located inside the microwave cavity. The lower end of the first push rod extends into the microwave cavity and is fixedly connected to the first microwave reed. The upper end of the first push rod extends into the cavity of the outer shell. The first spring is fitted on the first push rod and abuts against the upper end of the first push rod and the base of the outer shell.

[0009] The lower end of the second push rod extends into the microwave cavity and is fixedly connected to the second microwave spring. The upper end of the second push rod extends into the cavity of the outer shell. The second spring is fitted on the second push rod. The second spring abuts against the upper end of the second push rod and the base of the outer shell. The two ends of the second microwave spring are respectively aligned with the center inner conductor of the corresponding RF output end and the corresponding load inner conductor.

[0010] The load coaxial connector includes an inner load conductor, a load insulator, a microstrip segment, and an outer load conductor. The microstrip segment is welded and fixed to the inner load conductor. The load insulator is fitted on the outside of the inner load conductor. The inner load conductor is fixed inside the outer load conductor by the load insulator.

[0011] The RF input terminal and the RF output terminal each have a central inner conductor. The two ends of the first microwave spring are respectively aligned with the central inner conductor of the RF input terminal and the central inner conductor of the corresponding RF output terminal. The central inner conductor of the RF input terminal, the central inner conductor of the RF output terminal, and the inner conductor of the load connector all extend into the microwave cavity of the base.

[0012] To better understand the technical content of this invention, the microwave transmission mechanism with radio frequency coaxial load will be referred to as this microwave transmission mechanism.

[0013] As a preferred embodiment of this microwave transmission mechanism, the centerline of the load inner conductor, the centerline of the microstrip segment, and the centerline of the load outer conductor of the load coaxial connector are collinear.

[0014] As a preferred embodiment of this microwave transmission mechanism, the microstrip segment is a cylindrical non-inductive high-frequency resistor with a frequency of 18GHz, an impedance of 50Ω, a power capacity of 2W, a voltage standing wave ratio of ≤1.2, and an operating temperature of -55℃ to +125℃.

[0015] As a preferred material for this microwave transmission mechanism, the load insulator is made of polytetrafluoroethylene (PTFE).

[0016] As a preferred embodiment of this microwave transmission mechanism, the end face of the inner conductor of the load and the end face of the cylindrical non-inductive high-frequency resistor are fixed by soldering.

[0017] As a preferred embodiment of this microwave transmission mechanism, the RF input terminal is an input-type SMA coaxial connector, and the RF output terminals all adopt output-type SMA coaxial connectors.

[0018] As a preferred embodiment of this microwave transmission mechanism, the input type SMA coaxial connector and the output type SMA coaxial connector have the same structure. The input type SMA coaxial connector includes a central inner conductor, an insulator, and an outer conductor. The central inner conductor is installed inside the outer conductor through the insulator.

[0019] As a preferred embodiment of this microwave transmission mechanism, several RF output terminals and several load connectors are uniformly distributed in a circle around the RF input terminal.

[0020] As a preferred embodiment of this microwave transmission mechanism, the line connecting the center point of the RF input terminal projected on the base of the housing to the center point of the RF output terminal projected on the base of the housing is not collinear with the line connecting the center point of the corresponding RF input terminal projected on the base of the housing to the center point of the corresponding load connector projected on the base of the housing, and the length of the line connecting the center point of the RF input terminal projected on the base of the housing to the center point of the RF output terminal projected on the base of the housing is greater than the length of the line connecting the center point of the corresponding RF input terminal projected on the base of the housing to the center point of the corresponding load connector projected on the base of the housing.

[0021] This microwave transmission mechanism effectively solves the problems of signal leakage, mutual interference, and damage to the radio frequency source during the use of high-frequency multi-channel coaxial switches, ensuring high-quality transmission of radio frequency signals and improving the reliability of electronic countermeasures systems. To further enhance the reliability of high-frequency, high-power microwave electronic countermeasures systems, a 50Ω resistive load is connected to the unused transmission line to absorb reflected signals.

[0022] This microwave transmission mechanism adopts a columnar resistive coaxial load structure, consisting of an inner conductor and a microstrip segment, and has the following characteristics:

[0023] (1) The inner conductor of the load is mainly used to connect the coaxial transmission line of the coaxial switch for the transmission of microwave signals.

[0024] (2) The microstrip segment is a cylindrical non-inductive high-frequency resistor with a frequency of 18GHz, an impedance of 50Ω, a power capacity of 2W, a voltage standing wave ratio of ≤1.2, an operating temperature of -55℃~+125℃, and a size of φ1mm×3.3mm. It is used for absorbing microwave energy and impedance matching.

[0025] (3) The load insulator supports serve to fix the inner conductor and resistance. The material used is polytetrafluoroethylene. The load insulator has a low dielectric constant, good frequency characteristics, good environmental resistance, resistance to high and low temperatures, radiation resistance, and is not easily deformed. At the same time, the shape of the load insulator supports is designed as a stepped transformation structure to compensate for the discontinuity of the transmission line.

[0026] (4) The outer conductor is connected to the base of the coaxial switch, and the thread size is 1 / 4-36UNS-2A.

[0027] (5) The load inner conductor and microstrip segment are fixed by soldering.

[0028] The beneficial technical effects of this microwave transmission mechanism are as follows: It designs an SMA-type coaxial load that is directly built into the RF output terminal of the coaxial switch, with a frequency of 18GHz, a voltage standing wave ratio of less than 1.2, an absorption power of 2W, and an impedance of 50Ω. This effectively reduces signal interference from the unused RF port, while the energy of the reflected signal is absorbed by the coaxial load, protecting the RF source. Attached Figure Description

[0029] Figure 1 This is a bottom view of an embodiment of the microwave transmission mechanism.

[0030] Figure 2 yes Figure 1 A cross-sectional view along the AA direction.

[0031] Figure 3 This is a front view of the cavity cover and reed assembly of this microwave transmission mechanism embodiment.

[0032] Figure 4 yes Figure 3 A bottom view.

[0033] Figure 5 This is a cross-sectional view of the radio frequency input terminal of this microwave transmission mechanism embodiment.

[0034] Figure 6 This is a cross-sectional view of the load connector of this microwave transmission mechanism embodiment.

[0035] Figure 7 This is a left view of the microwave transmission mechanism in use according to an embodiment. Detailed Implementation

[0036] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0037] The terms “vertical,” “horizontal,” “left,” “right,” and similar expressions used in this document are for illustrative purposes only and do not represent the only possible implementation.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] Please see Figures 1 to 6 .

[0040] This microwave transmission mechanism includes an RF input terminal 21, six RF output terminals 22, six load connectors, and six sets of reed assemblies.

[0041] The RF input terminal 21, six RF output terminals 22 and six load connectors are all fixed on the outside of the base 11 of the coaxial switch. The base 11 includes a cavity cover 11a and a seat body 11b. The end face of the seat body 11b near the cavity has a groove. The cavity cover 11a is fixedly connected to the end face of the seat body 11b near the cavity. A microwave cavity 11c is formed between the seat body 11b and the cavity cover 11a.

[0042] The RF input terminal 21 is an input-type SMA coaxial connector, and the RF output terminals 22 all use output-type SMA coaxial connectors. The input-type and output-type SMA coaxial connectors have the same structure. Taking the input-type SMA coaxial connector as an example: the input-type SMA coaxial connector includes a center inner conductor 21b, an insulator 21c, and an outer conductor 21a. The center inner conductor 21b is mounted inside the outer conductor 21a via the insulator 21c. The structure of the output-type SMA coaxial connector will not be described in detail.

[0043] The load coaxial connector 23 includes an inner load conductor 23b, a load insulator 23c, a microstrip segment, and an outer load conductor 23a.

[0044] The microstrip segment is a cylindrical non-inductive high-frequency resistor 23d with a frequency of up to 18GHz, an impedance of 50Ω, a power capacity of 2W, a voltage standing wave ratio of ≤1.2, an operating temperature of -55℃~+115℃, and dimensions of φ1mm×3.3mm. It is used for absorbing microwave energy and impedance matching.

[0045] The cylindrical non-inductive high-frequency resistor 23d is welded and fixed to the inner conductor 23b of the load. The load insulator 23c is fitted on the outside of the inner conductor 23b of the load. The load insulator 23c and the inner conductor 23b of the load are located inside the outer conductor 23a of the load. The inner conductor 23b of the load is fixed inside the outer conductor 23a of the load through the load insulator 23c. The load insulator 23c plays the role of supporting and fixing the inner conductor 23b of the load and the cylindrical non-inductive high-frequency resistor 23d.

[0046] The six RF output terminals 22, six load connectors, and six sets of reed assemblies correspond one-to-one. The reed assembly includes a first microwave reed 24a, a second microwave reed 24b, a first spring 24c, a first push rod 24e, a second spring 24d, and a second push rod 24f. The first microwave reed 24a and the second microwave reed 24b are located in the microwave cavity 11c. The lower end of the first push rod 24e extends into the microwave cavity 11c and is fixedly connected to the first microwave reed 24a. The upper end of the first push rod 24e extends into the cavity of the outer shell. The first spring 24c is fitted on the first push rod 24e. The first spring 24c abuts against the upper end of the first push rod 24e and the base 11 of the outer shell. The two ends of the first microwave reed 24a are respectively aligned with the center inner conductor 21b of the RF input terminal 21 and the center inner conductor 21b of the corresponding RF output terminal 22.

[0047] The lower end of the second push rod 24f extends into the microwave cavity 11c and is fixedly connected to the second microwave spring 24b. The upper end of the second push rod 24f extends into the cavity of the outer shell. The second spring 24d is fitted onto the second push rod 24f. The second spring 24d abuts against the upper end of the second push rod 24f and the base 11 of the outer shell. The two ends of the second microwave spring 24b are respectively aligned with the center inner conductor 21b and the corresponding load inner conductor 23b of the corresponding RF output terminal 22.

[0048] The RF input terminal 21 and the RF output terminal 22 each have a central inner conductor 21b. The central inner conductor 21b of the RF input terminal 21, the central inner conductor 21b of the RF output terminal 22, and the inner conductor of the load connector all extend into the microwave cavity 11c of the base 11.

[0049] The center line of the load inner conductor 23b, the center line of the cylindrical non-inductive high-frequency resistor 23d, and the center line of the load outer conductor 23a of the load coaxial connector 23 are collinear.

[0050] The load insulator 23c is made of polytetrafluoroethylene (PTFE), which has a low dielectric constant, good frequency characteristics, good environmental resistance, resistance to high and low temperatures, radiation resistance, and is not easily deformed. Meanwhile, the load insulator 23c is designed with a stepped transformation structure to compensate for discontinuities in the transmission line.

[0051] The inner conductor 23b of the load is fixed to the cylindrical non-inductive high-frequency resistor 23d by soldering. The outer conductor 23a of the load is connected to the base 11 of the coaxial switch by bolts with a thread size of 1 / 4-36UNS-2A.

[0052] The six RF output terminals 22 and the six load connectors are evenly distributed in a circle around the RF input terminal 21. The line connecting the center point of the projection of the RF input terminal 21 on the base 11 of the housing to the center point of the projection of the RF output terminal 22 on the base 11 of the housing is not collinear with the line connecting the center point of the projection of the corresponding RF input terminal 21 on the base 11 of the housing to the center point of the projection of the corresponding load connector on the base 11 of the housing. Furthermore, the length of the line connecting the center point of the projection of the RF input terminal 21 on the base 11 of the housing to the center point of the projection of the RF output terminal 22 on the base 11 of the housing is greater than the length of the line connecting the center point of the projection of the corresponding RF input terminal 21 on the base 11 of the housing to the center point of the projection of the corresponding load connector on the base 11 of the housing.

[0053] Starting from the RF input terminal 21, the lines are sequentially connected to the corresponding RF output terminal 22 and the corresponding load coaxial connector 23 to form a "7" shape. The "7" shape structure effectively reduces the outer diameter of the microwave transmission component, which can meet the requirement of miniaturization of the switch. At the same time, it effectively solves the problem of matching the RF coaxial transmission line with the coaxial load.

[0054] Please see Figure 7 .

[0055] This microwave transmission mechanism works in conjunction with the circuit control mechanism 4 and electromagnetic drive mechanism 3 of the coaxial switch. The circuit control mechanism 4 and electromagnetic drive mechanism 3 of the coaxial switch adopt conventional circuit control mechanism 4, and the electromagnetic drive mechanism 3 consists of multiple sets of balanced rotary electromagnetic systems. An "integrated" electromagnetic drive system is designed, characterized by connecting the external magnetic circuits of each battery system together, so that the electromagnetic drive force can be reliably operated while the size is smaller. The circuit control mechanism 4 controls the electromagnetic drive mechanism 3 to form a single-pole multi-throw magnetic holding structure, and the RF terminal matches the load. That is, each channel is a set of magnetic holding type single-pole double-throw system, which can be realized by the coaxial switch through the electromagnetic drive mechanism 3.

[0056] When the coaxial switch is working, the RF input terminal 21 and the RF output terminal 22 are connected through the first microwave reed 24a to transmit RF signals. When the coaxial switch is not working, the unused RF output terminal 22 is connected to the 50Ω load terminal, and the reflected signal is absorbed by the load, which improves the anti-interference capability of the coaxial switch, effectively protects the front-end power amplifier, and improves the system's safety.

[0057] The above description is only one embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the principle of the present invention, and these should also be considered to fall within the protection scope of the present invention.

Claims

1. A microwave transmission mechanism with a radio frequency coaxial load, characterized in that: it comprises a radio frequency input end, a plurality of radio frequency output ends, a plurality of load connectors and a plurality of reed assemblies; the radio frequency input end, the plurality of radio frequency output ends and the plurality of load connectors are fixed outside the base of the coaxial switch, and the base of the coaxial switch is internally provided with a microwave cavity; the plurality of radio frequency output ends, the plurality of load connectors and the plurality of reed assemblies are in one-to-one correspondence, and the reed assembly comprises a first microwave reed, a second microwave reed, a first spring, a first push rod, a second spring and a second push rod, the first microwave reed and the second microwave reed are located in the microwave cavity, the lower end of the first push rod extends into the microwave cavity and is fixedly connected with the first microwave reed, the upper end of the first push rod extends to the cavity of the shell, the first spring is sleeved on the first push rod, and the first spring is respectively abutted between the upper end of the first push rod and the base of the shell; the lower end of the second push rod extends into the microwave cavity and is fixedly connected with the second microwave reed, the upper end of the second push rod extends to the cavity of the shell, the second spring is sleeved on the second push rod, and the second spring is respectively abutted between the upper end of the second push rod and the base of the shell, and the two ends of the second microwave reed are respectively aligned with the center inner conductor of the corresponding radio frequency output end and the load inner conductor; the load coaxial connector comprises a load inner conductor, a load insulator, a microstrip section and a load outer conductor, the microstrip section is welded and fixed with the load inner conductor, the load insulator is sleeved outside the load inner conductor, and the load inner conductor is fixed in the load outer conductor through the load insulator; the radio frequency input end and the radio frequency output end respectively have a center inner conductor, the two ends of the first microwave reed are respectively aligned with the center inner conductor of the radio frequency input end and the center inner conductor of the corresponding radio frequency output end, and the center inner conductor of the radio frequency input end, the center inner conductor of the radio frequency output end and the inner conductor of the load connector all extend into the microwave cavity of the base; the center line of the load inner conductor of the load coaxial connector, the center line of the microstrip section and the center line of the load outer conductor are collinear; the microstrip section is a cylindrical non-inductive high-frequency resistor, the frequency reaches 18GHz, the impedance is 50Ω, the power capacity is 2W, the voltage standing wave ratio is ≤1.2, and the working temperature is -55℃-+125℃; the material of the load insulator is selected from polytetrafluoroethylene; the load inner conductor end face and the cylindrical non-inductive high-frequency resistor end face are fixed by soldering; the radio frequency input end is an input type SMA type coaxial connector, and the radio frequency output end adopts an output type SMA type coaxial connector; the input type SMA type coaxial connector and the output type SMA type coaxial connector have the same structure, the input type SMA type coaxial connector comprises a center inner conductor, an insulator and an outer conductor, and the center inner conductor is installed in the outer conductor through the insulator; the plurality of radio frequency output ends and the plurality of load connectors are uniformly distributed along the radio frequency input end as the center; ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The line connecting the projection center point of the radio frequency input end on the base of the shell to the projection center point of the radio frequency output end on the base of the shell is not collinear with the line connecting the projection center point of the corresponding radio frequency input end on the base of the shell to the projection center point of the corresponding load connector on the base of the shell, and the length of the line connecting the projection center point of the radio frequency input end on the base of the shell to the projection center point of the radio frequency output end on the base of the shell is greater than the length of the line connecting the projection center point of the corresponding radio frequency input end on the base of the shell to the projection center point of the corresponding load connector on the base of the shell; The lines between the radio frequency input end, the corresponding radio frequency output end and the corresponding load coaxial connector form a "7" shape in sequence.

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