Terahertz micro-coaxial integrated front-end

Abstract

The application discloses a terahertz micro-coaxial integrated front end, which comprises a micro-coaxial local oscillator driving frequency multiplier, a micro-coaxial coupler and a micro-coaxial terahertz frequency converter; the micro-coaxial local oscillator driving frequency multiplier receives an original local oscillator signal, performs frequency multiplication processing on the original local oscillator signal, and obtains a frequency-multiplied local oscillator signal; the micro-coaxial coupler is used for monitoring the output power of the micro-coaxial local oscillator driving frequency multiplier, and transmitting the frequency-multiplied local oscillator signal to the micro-coaxial terahertz frequency converter; the micro-coaxial terahertz frequency converter receives an original radio frequency signal and the frequency-multiplied local oscillator signal transmitted by the micro-coaxial coupler, performs frequency conversion processing on the frequency-multiplied local oscillator signal and the original radio frequency signal, and obtains an intermediate frequency signal. Compared with a traditional microstrip line structure, the micro-coaxial structure can make the isolation degree between various circuits higher, reduce mutual interference, is not affected by bending and cross coupling, is convenient for constructing complex circuits and devices, and thus realizes high integration of a circuit system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless communication, and particularly relates to a terahertz micro-coaxial integrated front end. BACKGROUND

[0002] After rapid development, the basic functional circuits of terahertz solid-state electronics have become mature, and system prototypes based on these single-function circuits have emerged one after another, and the application range covers many fields such as security inspection, high-speed communication, radar imaging, weather monitoring and biological medicine. At present, the terahertz solid-state electronic communication system being developed still faces many challenges, such as large size, complex circuit layout, and difficulty in integration and miniaturization. This is mainly because the terahertz solid-state circuit generally uses a waveguide structure to transmit electromagnetic waves, resulting in poor structural flexibility, and the processing of bending and twisting is also more complex. In order to solve these technical problems and meet the needs of future terahertz high-speed communication systems, multi-circuit integration, miniaturization and even chip have become the new development trend of current terahertz solid-state circuits.

[0003] Generally, the terahertz radio frequency front end needs to perform frequency conversion processing on the signal, and needs a frequency converter and a corresponding local oscillator driving circuit. The terahertz radio frequency front end needs a frequency converter, a frequency mixer and other components. In the traditional radio frequency front end, the frequency converter and other circuits are often packaged separately, and then connected through a waveguide flange. The connection of multiple metal cavities results in a large size, and the long circuit also causes a long transmission line, thereby causing the loss of the radio frequency front end to increase accordingly. SUMMARY

[0004] The purpose of the present application is to provide a terahertz micro-coaxial integrated front end to solve the technical problems of the conventional radio frequency front end in the prior art, that is, the size is large and the loss is high due to the separate packaging of each circuit. The preferred technical solutions in many technical solutions provided by the present application can produce many technical effects, which are described in detail below.

[0005] To achieve the above purpose, the present application provides the following technical solutions:

[0006] This application provides a terahertz microcoaxial integrated front end, comprising a local oscillator drive frequency multiplier, a microcoaxial coupler, and a microcoaxial terahertz frequency converter. The local oscillator drive frequency multiplier receives the original local oscillator signal and performs frequency multiplication processing on the original local oscillator signal to obtain a frequency-multiplied local oscillator signal. The microcoaxial coupler is used to monitor the output power of the local oscillator drive frequency multiplier and transmit the frequency-multiplied local oscillator signal to the microcoaxial terahertz frequency converter. The microcoaxial terahertz frequency converter receives the original radio frequency signal and the frequency multiplied signal transmitted by the microcoaxial coupler. The local oscillator signal is used to perform frequency conversion processing on the frequency-doubled local oscillator signal and the original radio frequency signal to obtain an intermediate frequency signal; the output terminal of the local oscillator driving frequency multiplier of the micro-coaxial cable is coaxially connected to the receiving terminal of the micro-coaxial coupler, the first receiving terminal of the micro-coaxial terahertz frequency converter is coaxially connected to the output terminal of the micro-coaxial coupler, and the second receiving terminal of the micro-coaxial terahertz frequency converter receives the original radio frequency signal; the receiving terminal of the local oscillator driving frequency multiplier of the micro-coaxial cable receives the original local oscillator signal, and the output terminal of the micro-coaxial terahertz frequency converter outputs the intermediate frequency signal.

[0007] In some embodiments, the terahertz micro-coaxial integrated front end further includes a micro-coaxial filter, which is coaxially connected to the second receiving end of the terahertz inverter of the micro-coaxial circuit; the micro-coaxial filter receives the original radio frequency signal and filters the original radio frequency signal to obtain a filtered radio frequency signal; the terahertz inverter of the micro-coaxial circuit performs frequency conversion processing on the frequency-doubled local oscillator signal and the filtered radio frequency signal to obtain the intermediate frequency signal.

[0008] In some embodiments, the terahertz microcoaxial integrated front end includes a first transition waveguide and a second transition waveguide of the microcoaxial system; a first end of the first transition waveguide of the microcoaxial system is coaxially connected to the output of the local oscillator drive frequency multiplier of the microcoaxial system, and a second end of the first transition waveguide of the microcoaxial system is coaxially connected to the receiving end of the microcoaxial coupler; a first end of the second transition waveguide of the microcoaxial system is coaxially connected to the microcoaxial filter, and a second end of the second transition waveguide of the microcoaxial system is coaxially connected to the second receiving end of the terahertz frequency converter of the microcoaxial system.

[0009] In some embodiments, the microcoaxial coupler includes a transmission waveguide of the microcoaxial axis, an isolation waveguide of the microcoaxial axis, and multiple branch structures of the microcoaxial axis. One end of the transmission waveguide of the microcoaxial axis is the receiving end of the microcoaxial coupler, and the other end of the transmission waveguide of the microcoaxial axis is the output end of the microcoaxial coupler. One end of the isolation waveguide of the microcoaxial axis is a detection port, which couples out a portion of the energy from the frequency-doubled local oscillator signal to detect the output power of the local oscillator driving the frequency multiplier of the microcoaxial axis. The other end of the isolation waveguide of the microcoaxial axis is an isolation port, which is used to reduce internal electromagnetic interference. The transmission waveguide of the microcoaxial axis and the isolation waveguide of the microcoaxial axis are coaxially connected through the multiple branch structures of the microcoaxial axis and are symmetrically arranged about the multiple branch structures of the microcoaxial axis. There is a preset interval between the multiple branch structures of the microcoaxial axis.

[0010] In some embodiments, the microcoaxial local oscillator drive frequency multiplier includes an inner conductor lead-out direct connection structure, a transition structure of the microcoaxial input waveguide, an input waveguide for receiving the original local oscillator signal, a microcoaxial input low-pass filter for filtering the original local oscillator signal, a diode pair for frequency multiplication and amplification of the filtered original local oscillator signal to generate the frequency-doubled local oscillator signal, a transition structure of the microcoaxial output waveguide, two microcoaxial matching circuits, and an output waveguide for transmitting the frequency-doubled local oscillator signal. The first end of the inner conductor lead-out direct connection structure is directly connected to an external DC bias circuit through the inner conductor of the microcoaxial circuit, and the second end of the inner conductor lead-out direct connection structure is coaxially connected to the transition structure of the microcoaxial input waveguide. The inner conductor lead-out direct connection structure is used to introduce the bias voltage of the external DC bias circuit to reduce distortion.

[0011] In some embodiments, the first end of the transition structure of the input waveguide of the microcoaxial cable is coaxially connected to the second end of the direct-connect structure of the inner conductor; the second end of the transition structure of the input waveguide of the microcoaxial cable is connected to the input waveguide; and the third end of the transition structure of the input waveguide of the microcoaxial cable is coaxially connected to the input low-pass filter of the microcoaxial cable. The first end of the diode pair is coaxially connected to the input low-pass filter of the microcoaxial cable through one of the microcoaxial matching circuits, and the second end of the diode pair is coaxially connected to the first end of the transition structure of the output waveguide of the microcoaxial cable through another of the microcoaxial matching circuits, wherein the second end of the transition structure of the output waveguide of the microcoaxial cable is coaxially connected to the output waveguide.

[0012] In some embodiments, the transition structure of the input waveguide of the microcoaxial cable includes an input probe, which extends into the interior of the input waveguide through the inner conductor of the transition structure, for impedance matching between the transition structure of the input waveguide and the input waveguide; the transition structure of the output waveguide of the microcoaxial cable includes an output probe, which extends into the interior of the output waveguide through the inner conductor of the transition structure, for impedance matching between the transition structure of the output waveguide and the output waveguide.

[0013] In some embodiments, the first end of the input waveguide is the receiving end of the local oscillator driven frequency multiplier of the micro-coaxial circuit, and the second end of the input waveguide is connected to the input probe; the first end of the input probe is coaxially connected to the second end of the inner conductor lead-out direct connection structure, the second end of the input probe is connected to the second end of the input waveguide, and the third end of the input probe is coaxially connected to the first end of the input low-pass filter of the micro-coaxial circuit; the first end of the output probe is coaxially connected to the diode pair; the first end of the output waveguide is connected to the second end of the output probe, and the second end of the output waveguide is the output end of the local oscillator driven frequency multiplier of the micro-coaxial circuit.

[0014] In some examples, the microcoaxial terahertz inverter includes a microcoaxial local oscillator waveguide for receiving the frequency-doubled local oscillator signal, a microcoaxial radio frequency waveguide for receiving the original radio frequency signal or the filtered radio frequency signal, and a rectangular microcoaxial-SMA coaxial transition structure for converting the rectangular waveguide structure into a circular structure. The microcoaxial local oscillator waveguide, the microcoaxial radio frequency waveguide, and the rectangular microcoaxial-SMA coaxial transition structure are all coaxially connected. The first end of the microcoaxial local oscillator waveguide is the first receiving end of the microcoaxial terahertz inverter, the first end of the microcoaxial radio frequency waveguide is the second receiving end of the microcoaxial terahertz inverter, and the first end of the rectangular microcoaxial-SMA coaxial transition structure is the output end of the microcoaxial terahertz inverter.

[0015] In some examples, the microcoaxial terahertz inverter includes a local oscillator probe, a microcoaxial local oscillator low-pass filter, a microcoaxial intermediate frequency (IF) low-pass filter, a diode for frequency conversion processing, and an RF probe. A first end of the local oscillator probe is coaxially connected to a second end of the microcoaxial local oscillator waveguide, a second end of the local oscillator probe is coaxially connected to a first end of the microcoaxial local oscillator low-pass filter, and a third end of the local oscillator probe is coaxially connected to a first end of the microcoaxial IF low-pass filter, wherein the second end of the microcoaxial IF low-pass filter is coaxially connected to a second end of the rectangular microcoaxial-SMA coaxial transition structure. A first end of the diode is coaxially connected to a second end of the microcoaxial local oscillator low-pass filter, and a second end of the diode is coaxially connected to a first end of the RF probe, wherein the second end of the RF probe is coaxially connected to a second end of the microcoaxial RF waveguide. The inner conductor of the local oscillator probe extends into the interior of the microcoaxial local oscillator waveguide, and the inner conductor of the RF probe extends into the interior of the microcoaxial RF waveguide.

[0016] Implementing one of the above-described technical solutions of this application has the following advantages or beneficial effects: In this application, the local oscillator drive frequency multiplier, micro-coaxial coupler, and terahertz frequency converter are designed based on a micro-coaxial structure, and each circuit is coaxially connected based on its own inner conductor to achieve signal transmission and processing. In this case, compared with the traditional microstrip line structure, the micro-coaxial structure can achieve higher isolation between the circuits, reduce mutual interference, and the performance of the micro-coaxial structure is not affected by bending and cross-coupling, making it easy to construct complex circuits and devices, thereby achieving a high degree of integration of the circuit system; in addition, the coaxial connection of each circuit facilitates circuit integration and is easy to connect, thereby making the size of the terahertz micro-coaxial integrated front end smaller, and thus reducing the overall circuit loss. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0018] Figure 1 This is a schematic diagram of the structure of the terahertz micro-coaxial integrated front end according to an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of the rectangular micro-coaxial cable according to an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of the internal structure of the terahertz micro-coaxial integrated front end according to an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the structure of the inner conductor of the terahertz micro-coaxial integrated front end according to an embodiment of this application;

[0022] Figure 5 This is a schematic diagram of the inner conductor of the micro coaxial coupler according to an embodiment of this application;

[0023] Figure 6 This is a structural block diagram of the local oscillator drive frequency multiplier of the micro coaxial cable according to an embodiment of this application;

[0024] Figure 7 This is a schematic diagram of the structure of the micro-coaxial local oscillator drive frequency multiplier according to an embodiment of this application;

[0025] Figure 8 This is a schematic diagram of the internal structure of the local oscillator drive frequency multiplier of the micro-coaxial structure according to an embodiment of this application;

[0026] Figure 9 This is a schematic diagram of the inner conductor of the local oscillator drive frequency multiplier of the micro-coaxial structure according to an embodiment of this application;

[0027] Figure 10 This is a schematic diagram of the structure of the inner conductor of the micro-coaxial terahertz frequency converter according to an embodiment of this application.

[0028] In the figure: 1. Terahertz microcoaxial integrated front end; 2. Microcoaxial coupler; 3. Local oscillator drive frequency multiplier of microcoaxial; 4. Terahertz frequency converter of microcoaxial; 5. Microcoaxial filter; 6. First transition waveguide of microcoaxial; 7. Second transition waveguide of microcoaxial;

[0029] S1, Receiver of the local oscillator-driven frequency multiplier in the micro-coaxial cable; S2, Output of the local oscillator-driven frequency multiplier in the micro-coaxial cable; 30, Direct connection structure of the inner conductor lead-out; 31, Transition structure of the input waveguide in the micro-coaxial cable; 32, Input waveguide; 33, Input low-pass filter in the micro-coaxial cable; 34, Diode pair; 35, Transition structure of the output waveguide in the micro-coaxial cable; 36, Matching circuit in the micro-coaxial cable; 37, Output waveguide; 310, Input probe; 350, Output probe;

[0030] S3, receiver of the microcoaxial coupler; S4, output of the microcoaxial coupler; 20, transmission waveguide of the microcoaxial coupler; 21, isolation waveguide of the microcoaxial coupler; 22, branch structure of the microcoaxial coupler;

[0031] S5, First receiver of the micro-coaxial terahertz inverter; S6, Second receiver of the micro-coaxial terahertz inverter; S7, Output of the micro-coaxial terahertz inverter; 40, Local oscillator waveguide of the micro-coaxial inverter; 41, Radio frequency waveguide of the micro-coaxial inverter; 42, Rectangular micro-coaxial-SMA coaxial transition structure; 43, Local oscillator probe; 44, Local oscillator low-pass filter of the micro-coaxial inverter; 45, Intermediate frequency low-pass filter of the micro-coaxial inverter; 46, Diode; 47, Radio frequency probe. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, various exemplary embodiments described below will be referenced to the accompanying drawings, which form part of the exemplary embodiments and depict various exemplary embodiments that may be adopted to implement this application. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. It should be understood that they are merely examples of processes, methods, and apparatuses consistent with some aspects of this application disclosed as detailed in the appended claims, and other embodiments may be used, or structural and functional modifications may be made to the embodiments listed herein without departing from the scope and spirit of this application.

[0033] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the referred element must have a specific orientation, or be constructed and operated in a specific orientation. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. The term "multiple" means two or more. The terms "connected" and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, integral connections, mechanical connections, electrical connections, communication connections, direct connections, indirect connections through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more of the related listed items. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] To illustrate the technical solutions described in this application, specific embodiments are provided below, showing only the parts related to the embodiments of this application.

[0035] like Figure 1 As shown, this application provides a terahertz micro-coaxial integrated front end 1, including a micro-coaxial local oscillator drive frequency multiplier 3, a micro-coaxial coupler 2, and a micro-coaxial terahertz frequency converter 4.

[0036] In some embodiments, the micro-coaxial local oscillator drive frequency multiplier 3 can receive the original local oscillator signal, perform frequency multiplication on the original local oscillator signal to obtain a frequency-doubled local oscillator signal; the micro-coaxial coupler 2 can be used to monitor the output power of the micro-coaxial local oscillator drive frequency multiplier 3 and transmit the frequency-doubled local oscillator signal to the micro-coaxial terahertz frequency converter 4; the micro-coaxial terahertz frequency converter 4 can receive the original radio frequency signal and the frequency-doubled local oscillator signal transmitted by the micro-coaxial coupler 2, perform frequency conversion on the frequency-doubled local oscillator signal and the original radio frequency signal to obtain an intermediate frequency signal.

[0037] In some embodiments, the terahertz microcoaxial integrated front-end 1 can use a rectangular microcoaxial cable for communication. For example... Figure 2 As shown, a rectangular micro coaxial cable may include an inner conductor, a dielectric support, and an outer shielding cavity. Specifically, the inner conductor may be a closed structure, and it may be disposed inside the outer shielding cavity. A dielectric support is disposed between the inner conductor and the outer shielding cavity, and signals can be transmitted through the inner conductor.

[0038] In some embodiments, the transmission mode of the rectangular microcoaxial cable is TEM mode. Therefore, using a rectangular microcoaxial cable for transmission has the advantages of low dispersion and low loss, enabling the terahertz microcoaxial integrated front-end 1 to operate over a wider operating frequency range.

[0039] In summary, traditional rectangular waveguides exhibit high-pass characteristics, but fixed-size rectangular waveguides can only transmit electromagnetic waves within a fixed frequency band and cannot achieve broadband transmission. Meanwhile, because the inner conductor of a rectangular microcoaxial cable is closed, it offers high isolation. Even when two rectangular microcoaxial cables are very close together, their mutual interference is minimal, allowing for very close wiring. Impedance can be easily altered by adjusting the dimensions of the inner conductor. Furthermore, the performance of rectangular microcoaxial cables is unaffected by bending and cross-coupling, facilitating the construction of complex circuits and devices, thereby enabling high-level integration of circuit systems.

[0040] In some embodiments, the local oscillator drive frequency multiplier 3 of the micro-coaxial can transmit signals based on a rectangular micro-coaxial line.

[0041] In some embodiments, such as Figure 1 , Figure 3 and Figure 4 As shown, the output terminal of the local oscillator drive frequency multiplier 3 of the micro-coaxial converter can be coaxially connected to the receiving terminal S3 of the micro-coaxial coupler 2, and the first receiving terminal S5 of the micro-coaxial terahertz frequency converter 4 can be coaxially connected to the output terminal S4 of the micro-coaxial coupler 2.

[0042] In some embodiments, the receiving end S3 of the micro-coaxial coupler 2 can be used to receive the frequency-doubled local oscillator signal from the local oscillator drive frequency multiplier 3 of the micro-coaxial coupler, and transmit it to the terahertz frequency converter 4 of the micro-coaxial coupler 2 via the output end S4 of the micro-coaxial coupler 2.

[0043] In some embodiments, the receiving end S1 of the micro-coaxial local oscillator drive frequency multiplier 3 can receive the original local oscillator signal, the output end S7 of the micro-coaxial terahertz frequency converter 4 can output the intermediate frequency signal, and the second receiving end S6 of the micro-coaxial terahertz frequency converter 4 can receive the original radio frequency signal.

[0044] In some embodiments, the terahertz micro-coaxial integrated front end 1 may further include a micro-coaxial filter 5, which may be coaxially connected to the second receiving end S6 of the micro-coaxial terahertz frequency converter 4; the micro-coaxial filter 5 may receive the original radio frequency signal, filter the original radio frequency signal, and obtain a filtered radio frequency signal.

[0045] In some embodiments, the micro-coaxial terahertz inverter 4 can perform frequency conversion processing on the frequency-doubled local oscillator signal and the filtered radio frequency signal to obtain an intermediate frequency signal. Specifically, the micro-coaxial terahertz inverter 4 can receive the original radio frequency signal or the filtered radio frequency signal, as well as the frequency-doubled local oscillator signal, and perform frequency conversion processing on the signals to obtain an intermediate frequency signal.

[0046] In some embodiments, the terahertz microcoaxial integrated front-end 1 may include a first transition waveguide 6 and a second transition waveguide 7 of the microcoaxial system. The first end of the first transition waveguide 6 may be coaxially connected to the output S2 of the local oscillator drive frequency multiplier of the microcoaxial system, and the second end of the first transition waveguide 6 may be coaxially connected to the receiving end S3 of the microcoaxial coupler 2. The first end of the second transition waveguide 7 may be coaxially connected to the microcoaxial filter 5, and the second end of the second transition waveguide 7 may be coaxially connected to the second receiving end S6 of the terahertz frequency converter of the microcoaxial system.

[0047] In some embodiments, the microcoaxial coupler 2 may include a microcoaxial transmission waveguide 20, a microcoaxial isolation waveguide 21, and a plurality of microcoaxial branch structures 22.

[0048] In some embodiments, such as Figure 5 As shown, one end of the micro-coaxial transmission waveguide 20 can be the receiving end S3 of the micro-coaxial coupler 2, and the other end of the micro-coaxial transmission waveguide 20 can be the output end S4 of the micro-coaxial coupler 2.

[0049] In some embodiments, one end of the microcoaxial isolation waveguide 21 can be a detection port, which can couple out a portion of the energy from the frequency-doubled local oscillator signal to detect the output power of the microcoaxial local oscillator driving the frequency multiplier 3. The other end of the microcoaxial isolation waveguide 21 can be an isolation port, which can be used to reduce internal electromagnetic interference.

[0050] In some embodiments, the transmission waveguide 20 of the microcoaxial cable can be coaxially connected to the isolation waveguide 21 of the microcoaxial cable through a plurality of microcoaxial branch structures 22, and symmetrically arranged about the plurality of microcoaxial branch structures 22. The plurality of microcoaxial branch structures 22 may have a preset interval between them.

[0051] In some embodiments, one end of the microcoaxial branch structure 22 can be coaxially connected to the microcoaxial transmission waveguide 20, and the other end of the microcoaxial branch structure 22 can be coaxially connected to the microcoaxial isolation waveguide 21.

[0052] In some embodiments, the length of the branch structure 22 of the microcoaxial can be equal to the spacing between the transmission waveguide 20 of the microcoaxial and the isolation waveguide 21 of the microcoaxial.

[0053] In some embodiments, such as Figure 6 As shown, the microcoaxial local oscillator drive frequency multiplier 3 includes an inner conductor lead-out direct connection structure 30, a transition structure 31 for the input waveguide of the microcoaxial, an input waveguide 32 for receiving the original local oscillator signal, a microcoaxial input low-pass filter 33 for filtering the original local oscillator signal, a diode pair 34 for frequency multiplication and amplification of the filtered original local oscillator signal to generate a frequency-doubled local oscillator signal, a transition structure 35 for the output waveguide of the microcoaxial, two microcoaxial matching circuits 36, and an output waveguide 37 for transmitting the frequency-doubled local oscillator signal.

[0054] In some embodiments, the first end of the inner conductor lead-out direct connection structure 30 can be directly connected to an external DC bias circuit through the inner conductor of the micro-coaxial circuit, and the second end of the inner conductor lead-out direct connection structure 30 can be coaxially connected to the transition structure 31 of the input waveguide of the micro-coaxial circuit. The inner conductor lead-out direct connection structure 30 can be used to introduce the bias voltage of the external DC bias circuit to reduce distortion.

[0055] In some embodiments, the external DC bias circuit can be directly fed to the local oscillator drive frequency multiplier 3 of the micro-coaxial circuit by leading out from the inner conductor through the SMA coaxial line and directly connecting to the inner conductor of the structure 30. Since the DC bias can be directly applied through the inner conductor, the volume can be reduced by 50% compared to the traditional frequency multiplier. The SMA (SubMiniature version A) coaxial line is an RF coaxial cable connector.

[0056] Traditional microstrip-based frequency multiplier structures often use quartz substrates or other materials, making it impossible for the inner conductor of the coaxial connector to connect directly. This necessitates an additional 5880 flexible substrate for transition, increasing circuit size, connection losses, and overall fabrication difficulty. In this embodiment, the inner conductor lead-out direct connection structure 30 can be formed by directly extending a rectangular microcoaxial line. Therefore, this embodiment offers advantages such as simple structure, convenient connection, low loss, and small size.

[0057] In some embodiments, the inner conductor of the inner conductor leading out direct connection structure 30 can extend from one end of the inner conductor leading out direct connection structure 30 to the other end, that is, it can be directly connected to the inner conductor of the inner conductor leading out direct connection structure 30 through both ends.

[0058] In some embodiments, such as Figure 7 to Figure 9 As shown, the first end of the transition structure 31 of the microcoaxial input waveguide can be coaxially connected to the second end of the inner conductor lead-out direct connection structure 30. The second end of the transition structure 31 of the microcoaxial input waveguide can be connected to the input waveguide 32. The third end of the transition structure 31 of the microcoaxial input waveguide can be coaxially connected to the microcoaxial input low-pass filter 33. The inner conductor of the transition structure 31 of the microcoaxial input waveguide can be directly connected to the inner conductor of the inner conductor lead-out direct connection structure 30, and the inner conductor of the transition structure 31 of the microcoaxial input waveguide can be directly connected to the inner conductor of the microcoaxial input low-pass filter 33.

[0059] In some embodiments, the first end of the diode pair 34 can be coaxially connected to the input low-pass filter 33 of the microcoaxial via a microcoaxial matching circuit 36, and the second end of the diode pair 34 can be coaxially connected to the first end of the transition structure 35 of the output waveguide of the microcoaxial via another microcoaxial matching circuit 36, wherein the second end of the transition structure 35 of the output waveguide of the microcoaxial is coaxially connected to the output waveguide 37.

[0060] In some embodiments, the transition structure 31 of the microcoaxial input waveguide may include an input probe 310, which can be formed by extending the inner conductor of the transition structure 31 into the interior of the input waveguide 32 for impedance matching between the transition structure 31 and the input waveguide 32. In this embodiment, when the transition structure 31 of the microcoaxial input waveguide transitions into the input waveguide 32, only the inner conductor needs to be extended outward, thus the structure is simple and the circuit size is small.

[0061] In some embodiments, the input probe 310 may be a T-shaped structure.

[0062] In some embodiments, the first end of the input waveguide 32 can be the receiving end S1 of the micro-coaxial local oscillator driving frequency multiplier 3, the second end of the input waveguide 32 can be connected to the input probe 310; the first end of the input probe 310 can be coaxially connected to the second end of the inner conductor lead-out direct connection structure 30, the second end of the input probe 310 can be connected to the second end of the input waveguide 32, and the third end of the input probe 310 can be coaxially connected to the first end of the micro-coaxial input low-pass filter 33.

[0063] In some embodiments, the inner conductor of the micro-coaxial input low-pass filter 33 may include multiple rectangular branches. Specifically, the inner conductor of the micro-coaxial input low-pass filter 33 may extend in a direction perpendicular to the inner conductor's extension direction to form multiple rectangular branches. This enables impedance variation, thereby achieving the performance of a resonant cavity and satisfying the filtering effect.

[0064] Compared to microstrip line filters, the microcoaxial input low-pass filter 33 has a structure that reduces the lateral length of the circuit and the overall size can be reduced by 20%.

[0065] In some embodiments, the inner conductor of one microcoaxial matching circuit 36 ​​can be directly connected to the inner conductor of the input low-pass filter 33 of the microcoaxial circuit, and the inner conductor of another microcoaxial matching circuit 36 ​​can be directly connected to the inner conductor of the transition structure 35 of the output waveguide of the microcoaxial circuit.

[0066] In some embodiments, diode pair 34 can be directly connected to the inner conductor of the micro-coaxial matching circuit 36 ​​across diode pair 34. In this case, multiple coaxial-to-microstrip line transitions can be omitted, making the circuit structure of the terahertz frequency multiplier more compact; the heat dissipation area of ​​diode pair 34 can be increased, reducing the impact of heat accumulation on the performance of the terahertz frequency multiplier.

[0067] Traditional frequency multiplier diode integration primarily relies on flip-chip technology, where the diode chip is discrete and manually assembled onto the circuit substrate using conductive adhesive or other materials. Therefore, in traditional frequency multipliers, only a small portion of the diode is connected to the external cavity. Since the external cavity is metal, diode heat dissipation mainly depends on thermal conduction with the cavity. Due to the small contact area with the metal, heat dissipation is difficult, and heat accumulation further degrades the frequency multiplier's performance.

[0068] In some embodiments, diode pair 34 can be Schottky diodes connected in parallel in phase.

[0069] In some embodiments, the microcoaxial local oscillator drive frequency multiplier 3 may include a microcoaxial arched matching structure for heat dissipation of the diode pair 34; the first end of the microcoaxial arched matching structure may be coaxially connected to the diode pair 34, and the microcoaxial arched matching structure may be coaxially connected to the transition structure 35 of the output waveguide of the microcoaxial.

[0070] In some embodiments, the transition structure 35 of the microcoaxial output waveguide may include an output probe 350, which may be formed by extending the inner conductor of the transition structure 35 of the microcoaxial output waveguide into the interior of the output waveguide 37 for impedance matching between the transition structure 35 and the output waveguide 37.

[0071] In some embodiments, the first end of the output probe 350 can be coaxially connected to the diode pair 34, or coaxially connected to the diode pair 34 through the arched matching structure of the micro-coaxial; the first end of the output waveguide 37 can be connected to the second end of the output probe 350, and the second end of the output waveguide 37 can be the output end of the local oscillator driving frequency multiplier 3 of the micro-coaxial.

[0072] In some embodiments, the microcoaxial terahertz inverter 4 may include a microcoaxial local oscillator waveguide 40 for receiving a frequency-doubled local oscillator signal, a microcoaxial radio frequency waveguide 41 for receiving a raw radio frequency signal or a filtered radio frequency signal, and a rectangular microcoaxial-SMA coaxial transition structure 42 for converting a rectangular waveguide structure into a circular structure. The microcoaxial local oscillator waveguide 40 can be coaxially connected to both the microcoaxial radio frequency waveguide 41 and the rectangular microcoaxial-SMA coaxial transition structure 42. Because the microcoaxial terahertz inverter 4 of this embodiment does not use a substrate structure and omits multiple coaxial-to-microstrip line transitions, the entire microcoaxial terahertz inverter 4 has a compact circuit structure, and its volume can be reduced by 40% compared to that of a conventional inverter, thereby achieving miniaturization.

[0073] In some embodiments, the first end of the micro-coaxial local oscillator waveguide 40 can be the first receiving end S5 of the micro-coaxial terahertz inverter 4, the first end of the micro-coaxial radio frequency waveguide 41 can be the second receiving end S6 of the micro-coaxial terahertz inverter 4, and the first end of the rectangular micro-coaxial-SMA coaxial transition structure 42 can be the output end S7 of the micro-coaxial terahertz inverter 4.

[0074] In some embodiments, such as Figure 10 As shown, the micro-coaxial terahertz inverter 4 may include a local oscillator probe 43, a micro-coaxial local oscillator low-pass filter 44, a micro-coaxial intermediate frequency low-pass filter 45, a diode 46 for frequency conversion processing, and an RF probe 47.

[0075] In some embodiments, the first end of the local oscillator probe 43 can be coaxially connected to the second end of the micro-coaxial local oscillator waveguide 40, the second end of the local oscillator probe 43 can be coaxially connected to the first end of the micro-coaxial local oscillator low-pass filter 44, and the third end of the local oscillator probe 43 can be coaxially connected to the first end of the micro-coaxial intermediate frequency low-pass filter 45, wherein the second end of the micro-coaxial intermediate frequency low-pass filter 45 can be coaxially connected to the second end of the rectangular micro-coaxial-SMA coaxial transition structure 42.

[0076] In some embodiments, the first end of diode 46 may be coaxially connected to the second end of micro-coaxial local oscillator low-pass filter 44, and the second end of diode 46 may be coaxially connected to the first end of RF probe 47, wherein the second end of RF probe 47 may be coaxially connected to the second end of micro-coaxial RF waveguide 41.

[0077] In some embodiments, the inner conductor of the local oscillator probe 43 may extend into the interior of the micro-coaxial local oscillator waveguide 40, and the inner conductor of the RF probe 47 may extend into the interior of the micro-coaxial RF waveguide 41. This enables impedance matching.

[0078] In some embodiments, the local oscillator low-pass filter 44 of the microcoaxial can be provided with a rectangular branch, and the local oscillator waveguide 40 of the microcoaxial can be a rectangular waveguide.

[0079] In some embodiments, diode 46 may be two Schottky diodes connected in anti-parallel.

[0080] In some embodiments, the filtered RF signal or the original RF signal, as well as the frequency-doubled local oscillator signal, can be fed into the corresponding rectangular waveguide port, respectively, and loaded onto the Schottky diode through their respective matching networks (RF matching circuit, local oscillator matching circuit) to participate in frequency conversion. The resulting intermediate frequency signal can finally be output by the micro coaxial intermediate frequency low-pass filter 45.

[0081] In some embodiments, the inner conductor of the micro-coaxial filter 5 may have multiple rectangular branches.

[0082] The embodiments of this application can integrate a frequency converter, frequency multiplier, filter and coupler based on a micro coaxial structure into a single module, thereby achieving miniaturization of the single-sideband receiver front-end circuit.

[0083] In this application, a local oscillator drive frequency multiplier 3, a micro-coaxial coupler 2, and a terahertz frequency converter 4 are designed based on a micro-coaxial structure. Each circuit is coaxially connected based on its own inner conductor to achieve signal transmission and processing. In this configuration, compared to traditional microstrip line structures, the micro-coaxial structure provides higher isolation between circuits, reducing mutual interference. Furthermore, the performance of the micro-coaxial structure is unaffected by bending and cross-coupling, facilitating the construction of complex circuits and devices, thereby achieving a high degree of circuit system integration. Additionally, the coaxial connection of each circuit facilitates circuit integration and easy connection, resulting in a smaller size for the terahertz micro-coaxial integrated front-end 1, thereby reducing overall circuit losses.

[0084] The above description is merely a preferred embodiment of this application. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this application. Furthermore, under the teachings of this application, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this application. Therefore, this application is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this application.

Claims

1. A terahertz micro-coaxial integrated front end, characterized in that, The system includes a microcoaxial local oscillator drive frequency multiplier, a microcoaxial coupler, and a microcoaxial terahertz frequency converter. The microcoaxial local oscillator drive frequency multiplier receives the original local oscillator signal and performs frequency multiplication processing on the original local oscillator signal to obtain a frequency-doubled local oscillator signal. The microcoaxial coupler is used to monitor the output power of the microcoaxial local oscillator drive frequency multiplier and transmit the frequency-doubled local oscillator signal to the microcoaxial terahertz frequency converter. The microcoaxial terahertz frequency converter receives the original radio frequency signal and the frequency-doubled local oscillator signal transmitted by the microcoaxial coupler, and performs frequency conversion processing on the frequency-doubled local oscillator signal and the original radio frequency signal to obtain an intermediate frequency signal. The output terminal of the local oscillator drive frequency multiplier of the micro-coaxial cable is coaxially connected to the receiving terminal of the micro-coaxial coupler. The first receiving terminal of the micro-coaxial terahertz frequency converter is coaxially connected to the output terminal of the micro-coaxial coupler. The second receiving terminal of the micro-coaxial terahertz frequency converter receives the original radio frequency signal. The receiving end of the micro-coaxial local oscillator drive frequency multiplier receives the original local oscillator signal, and the output end of the micro-coaxial terahertz frequency converter outputs the intermediate frequency signal; the micro-coaxial terahertz frequency converter includes a micro-coaxial local oscillator waveguide for receiving the frequency multiplied local oscillator signal, a micro-coaxial radio frequency waveguide for receiving the original radio frequency signal or the filtered radio frequency signal, and a rectangular micro-coaxial-SMA coaxial transition structure for converting the rectangular waveguide structure into a circular structure. The micro-coaxial local oscillator waveguide, the micro-coaxial radio frequency waveguide, and the rectangular micro-coaxial-SMA coaxial transition structure are all coaxially connected.

2. The terahertz micro-coaxial integrated front end according to claim 1, characterized in that, The terahertz micro-coaxial integrated front end also includes a micro-coaxial filter, which is coaxially connected to the second receiving end of the terahertz frequency converter of the micro-coaxial circuit. The micro-coaxial filter receives the original radio frequency signal and filters it to obtain a filtered radio frequency signal. The terahertz frequency converter of the micro-coaxial circuit performs frequency conversion processing on the frequency-doubled local oscillator signal and the filtered radio frequency signal to obtain the intermediate frequency signal.

3. The terahertz micro-coaxial integrated front end according to claim 2, characterized in that, The terahertz micro-coaxial integrated front end includes a first transition waveguide and a second transition waveguide of the micro-coaxial system. The first end of the first transition waveguide is coaxially connected to the output of the local oscillator drive frequency multiplier of the micro-coaxial system, and the second end of the first transition waveguide is coaxially connected to the receiving end of the micro-coaxial coupler. The first end of the second transition waveguide is coaxially connected to the micro-coaxial filter, and the second end of the second transition waveguide is coaxially connected to the second receiving end of the terahertz frequency converter of the micro-coaxial system.

4. The terahertz micro-coaxial integrated front end according to claim 1, characterized in that, The microcoaxial coupler includes a microcoaxial transmission waveguide, a microcoaxial isolation waveguide, and multiple microcoaxial branch structures. One end of the transmission waveguide of the microcoaxial cable is the receiving end of the microcoaxial coupler, and the other end of the transmission waveguide of the microcoaxial cable is the output end of the microcoaxial coupler. One end of the isolation waveguide of the micro-coaxial cable is a detection port, which couples out a portion of the energy from the frequency-doubled local oscillator signal to detect the output power of the local oscillator driving the frequency doubler of the micro-coaxial cable. The other end of the isolation waveguide of the micro-coaxial cable is an isolation port, which is used to reduce internal electromagnetic interference. The transmission waveguide and isolation waveguide of the microcoaxial cable are coaxially connected through the branch structures of the multiple microcoaxial cables and are symmetrically arranged about the branch structures of the multiple microcoaxial cables. The branch structures of the multiple microcoaxial cables have a preset interval.

5. The terahertz micro-coaxial integrated front end according to claim 1, characterized in that, The microcoaxial local oscillator drive frequency multiplier includes an inner conductor lead-out direct connection structure, a transition structure for the input waveguide of the microcoaxial, an input waveguide for receiving the original local oscillator signal, an input low-pass filter for filtering the original local oscillator signal, a pair of diodes for frequency multiplication and amplification of the filtered original local oscillator signal to generate the frequency-doubled local oscillator signal, a transition structure for the output waveguide of the microcoaxial, two microcoaxial matching circuits, and an output waveguide for transmitting the frequency-doubled local oscillator signal. The first end of the inner conductor lead-out direct connection structure is directly connected to the external DC bias circuit through the inner conductor of the micro-coaxial circuit. The second end of the inner conductor lead-out direct connection structure is coaxially connected to the transition structure of the input waveguide of the micro-coaxial circuit. The inner conductor lead-out direct connection structure is used to introduce the bias voltage of the external DC bias circuit to reduce distortion.

6. The terahertz micro-coaxial integrated front end according to claim 5, characterized in that, The first end of the transition structure of the input waveguide of the microcoaxial cable is coaxially connected to the second end of the direct connection structure of the inner conductor; the second end of the transition structure of the input waveguide of the microcoaxial cable is connected to the input waveguide; and the third end of the transition structure of the input waveguide of the microcoaxial cable is coaxially connected to the input low-pass filter of the microcoaxial cable. The first end of the diode pair is coaxially connected to the input low-pass filter of the microcoaxial circuit through one of the microcoaxial matching circuits, and the second end of the diode pair is coaxially connected to the first end of the transition structure of the output waveguide of the microcoaxial circuit through another of the microcoaxial matching circuits, wherein the second end of the transition structure of the output waveguide of the microcoaxial circuit is coaxially connected to the output waveguide.

7. The terahertz micro-coaxial integrated front end according to claim 5, characterized in that, The transition structure of the microcoaxial input waveguide includes an input probe, which is formed by extending into the interior of the input waveguide through the inner conductor of the transition structure of the microcoaxial input waveguide, for impedance matching between the transition structure of the microcoaxial input waveguide and the input waveguide. The transition structure of the microcoaxial output waveguide includes an output probe, which is formed by extending into the interior of the output waveguide through the inner conductor of the transition structure of the microcoaxial output waveguide, for impedance matching between the transition structure of the microcoaxial output waveguide and the output waveguide.

8. The terahertz micro-coaxial integrated front end according to claim 7, characterized in that, The first end of the input waveguide is the receiving end of the local oscillator driven frequency multiplier of the micro-coaxial circuit, and the second end of the input waveguide is connected to the input probe. The first end of the input probe is coaxially connected to the second end of the direct connection structure of the inner conductor, and the second end of the input probe is connected to the second end of the input waveguide. The third end of the input probe is coaxially connected to the first end of the input low-pass filter of the micro-coaxial circuit. The first end of the output probe is coaxially connected to the diode pair. The first end of the output waveguide is connected to the second end of the output probe, and the second end of the output waveguide is the output end of the local oscillator driven frequency multiplier of the micro-coaxial circuit.

9. The terahertz micro-coaxial integrated front end according to claim 2, characterized in that, The first end of the local oscillator waveguide of the micro-coaxial converter is the first receiving end of the micro-coaxial terahertz frequency converter, the first end of the radio frequency waveguide of the micro-coaxial converter is the second receiving end of the micro-coaxial terahertz frequency converter, and the first end of the rectangular micro-coaxial-SMA coaxial transition structure is the output end of the micro-coaxial terahertz frequency converter.

10. The terahertz micro-coaxial integrated front end according to claim 9, characterized in that, The microcoaxial terahertz frequency converter includes a local oscillator probe, a microcoaxial local oscillator low-pass filter, a microcoaxial intermediate frequency low-pass filter, a diode for frequency conversion processing, and an RF probe. The first end of the local oscillator probe is coaxially connected to the second end of the local oscillator waveguide of the micro-coaxial structure, the second end of the local oscillator probe is coaxially connected to the first end of the local oscillator low-pass filter of the micro-coaxial structure, and the third end of the local oscillator probe is coaxially connected to the first end of the intermediate frequency low-pass filter of the micro-coaxial structure, wherein the second end of the intermediate frequency low-pass filter of the micro-coaxial structure is coaxially connected to the second end of the rectangular micro-coaxial-SMA coaxial transition structure. The first end of the diode is coaxially connected to the second end of the local oscillator low-pass filter of the micro-coaxial circuit, and the second end of the diode is coaxially connected to the first end of the radio frequency probe, wherein the second end of the radio frequency probe is coaxially connected to the second end of the radio frequency waveguide of the micro-coaxial circuit. The inner conductor of the local oscillator probe extends into the interior of the micro-coaxial local oscillator waveguide, and the inner conductor of the radio frequency probe extends into the interior of the micro-coaxial radio frequency waveguide.

Images