Terahertz micro coaxial integrated front end

Abstract

The invention discloses a terahertz micro-coaxial integrated front end. The terahertz micro-coaxial integrated front end comprises a micro-coaxial local oscillator driving frequency multiplier, a micro-coaxial coupler and a micro-coaxial terahertz frequency converter, a micro-coaxial local oscillator drives a frequency multiplier to receive the original local oscillator signal, frequency multiplication processing is carried out on the original local oscillator signal, and a frequency multiplication local oscillator signal is obtained; the micro-coaxial coupler is used for monitoring the output power of the micro-coaxial local oscillator driving frequency multiplier and transmitting a frequency multiplication local oscillator signal to the micro-coaxial terahertz frequency converter; the micro-coaxial terahertz frequency converter receives the original radio frequency signal and the frequency doubling local oscillator signal transmitted by the micro-coaxial coupler, and performs frequency conversion processing on the frequency doubling local oscillator signal and the original radio frequency signal to obtain an intermediate frequency signal. Compared with a traditional microstrip line structure, the microstrip line structure based on the micro-coaxial structure can enable the isolation degree between circuits to be higher, reduce mutual interference, is not affected by bending and cross coupling, facilitates the construction of complex circuits and devices, and achieves the high integration of a circuit system.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technology, and in particular to a terahertz micro-coaxial integrated front end. Background Art

[0002] After rapid development, the basic functional circuits of terahertz solid-state electronics have matured, and system prototypes based on these single-function circuits have been launched one after another, with applications covering many fields such as security inspection, high-speed communication, radar imaging, meteorological monitoring, and biomedicine. At present, the terahertz solid-state electronics communication systems under development still face many challenges, such as large size, complex circuit layout, and difficulty in integration and miniaturization. This is mainly because terahertz solid-state circuits generally use waveguide structures to transmit electromagnetic waves, resulting in poor structural flexibility and complex bending and twisting processing. In order to solve these technical problems and meet the needs of future terahertz high-speed communication systems, multi-circuit integration, miniaturization, and even chipization have become the new development trend of current terahertz solid-state circuits.

[0003] Generally speaking, the terahertz RF front end needs to process the signal in frequency conversion, which requires a frequency converter and a corresponding local oscillator drive circuit. The terahertz RF front end requires multiple components such as a frequency converter and a mixer. In traditional RF front ends, circuits such as frequency converters are often packaged separately and then connected through waveguide flanges. Multiple metal cavities are connected, resulting in a larger volume. At the same time, longer circuits also result in longer transmission lines, which leads to a corresponding increase in the loss of the RF front end. Summary of the invention

[0004] The purpose of this application is to provide a terahertz micro-coaxial integrated front end to solve the technical problem that each circuit of the traditional radio frequency front end is separately packaged in the prior art, resulting in a large size and high loss. The preferred technical solution among the many technical solutions provided in this application can produce many technical effects as described below.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] The present application provides a terahertz micro-coaxial integrated front end, comprising a micro-coaxial local oscillator driven frequency multiplier, a micro-coaxial coupler and a micro-coaxial terahertz frequency converter; the micro-coaxial local oscillator driven 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 to monitor the output power of the micro-coaxial local oscillator driven frequency multiplier, and transmit the frequency multiplied local oscillator signal to the micro-coaxial terahertz frequency converter; the micro-coaxial terahertz frequency converter receives the original radio frequency signal and the frequency multiplied local oscillator signal transmitted by the micro-coaxial coupler. The micro-coaxial terahertz frequency converter is coaxially connected to the output end of the micro-coaxial local oscillator driving the frequency multiplier, and the micro-coaxial terahertz frequency converter is coaxially connected to the output end of the micro-coaxial coupler, and the second receiving end of the micro-coaxial terahertz frequency converter receives the original RF signal; the receiving end of the micro-coaxial local oscillator driving the frequency multiplier receives the original local oscillator signal, and the output end of the micro-coaxial terahertz frequency converter outputs the intermediate frequency signal.

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

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

[0009] In some embodiments, the micro-coaxial coupler includes a micro-coaxial transmission waveguide, a micro-coaxial isolation waveguide and a plurality of micro-coaxial branch structures; one end of the micro-coaxial transmission waveguide is the receiving end of the micro-coaxial coupler, and the other end of the micro-coaxial transmission waveguide is the output end of the micro-coaxial coupler; one end of the micro-coaxial isolation waveguide is a detection port, and the detection port couples part of the energy from the frequency-doubled local oscillator signal to detect the output power of the micro-coaxial local oscillator-driven frequency doubler, and the other end of the micro-coaxial isolation waveguide is an isolation port, and the isolation port is used to reduce internal electromagnetic interference; the micro-coaxial transmission waveguide and the micro-coaxial isolation waveguide are coaxially connected through the plurality of micro-coaxial branch structures, and are symmetrically arranged about the plurality of micro-coaxial branch structures, and there is a preset interval between the plurality of micro-coaxial branch structures.

[0010] In some embodiments, the micro-coaxial local oscillator driven frequency multiplier includes an inner conductor lead-out direct connection structure, a transition structure of the micro-coaxial input waveguide, an input waveguide for receiving the original local oscillator signal, a micro-coaxial input low-pass filter for filtering the original local oscillator signal, a diode pair for frequency multiplying and amplifying the filtered original local oscillator signal to generate the frequency multiplied local oscillator signal, a transition structure of the micro-coaxial output waveguide, two micro-coaxial matching circuits and an output waveguide for transmitting the frequency multiplied 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 micro-coaxial, the second end of the inner conductor lead-out direct connection structure is coaxially connected to the transition structure of the micro-coaxial input waveguide, and 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 micro-coaxial input waveguide is coaxially connected to the second end of the inner conductor lead-out direct connection structure, the second end of the transition structure of the micro-coaxial input waveguide is connected to the input waveguide, and the third end of the transition structure of the micro-coaxial input waveguide is coaxially connected to the micro-coaxial input low-pass filter; the first end of the diode pair is coaxially connected to the micro-coaxial input low-pass filter through one of the micro-coaxial matching circuits, the second end of the diode pair is coaxially connected to the first end of the transition structure of the micro-coaxial output waveguide through another micro-coaxial matching circuit, wherein the second end of the transition structure of the micro-coaxial output waveguide is coaxially connected to the output waveguide.

[0012] In some embodiments, the transition structure of the micro-coaxial input waveguide includes an input probe, which is formed by extending into the interior of the input waveguide through an inner conductor of the transition structure of the micro-coaxial input waveguide, and is used for impedance matching between the transition structure of the micro-coaxial input waveguide and the input waveguide; the transition structure of the micro-coaxial output waveguide includes an output probe, which is formed by extending into the interior of the output waveguide through an inner conductor of the transition structure of the micro-coaxial output waveguide, and is used for impedance matching between the transition structure of the micro-coaxial 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, 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; 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.

[0014] In some examples, the micro-coaxial terahertz converter includes a micro-coaxial local oscillator waveguide for receiving the frequency-doubled 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 a rectangular waveguide structure into a circular structure. The micro-coaxial local oscillator waveguide is coaxially connected to the micro-coaxial radio frequency waveguide and the rectangular micro-coaxial-SMA coaxial transition structure; the first end of the micro-coaxial local oscillator waveguide is the first receiving end of the micro-coaxial terahertz converter, the first end of the micro-coaxial radio frequency waveguide is the second receiving end of the micro-coaxial terahertz converter, and the first end of the rectangular micro-coaxial-SMA coaxial transition structure is the output end of the micro-coaxial terahertz converter.

[0015] In some examples, the micro-coaxial terahertz converter includes a local oscillator probe, a micro-coaxial local oscillator low-pass filter, a micro-coaxial intermediate frequency low-pass filter, a diode for frequency conversion processing, and a radio frequency probe; the first end of the local oscillator probe is coaxially connected to the second end of the micro-coaxial local oscillator waveguide, the second end of the local oscillator probe is coaxially connected to the first end of the micro-coaxial local oscillator low-pass filter, the third end of the local oscillator probe is coaxially connected to the first end of the micro-coaxial intermediate frequency low-pass filter, wherein the second end of the micro-coaxial intermediate frequency low-pass filter 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 micro-coaxial local oscillator low-pass filter, 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 micro-coaxial radio frequency waveguide; the inner conductor of the local oscillator probe extends to the inside of the micro-coaxial local oscillator waveguide, and the inner conductor of the radio frequency probe extends to the inside of the micro-coaxial radio frequency waveguide.

[0016] Implementing one of the above technical solutions of the present application has the following advantages or beneficial effects: In the present application, the local oscillator driven frequency multiplier, micro-coaxial coupler and terahertz frequency converter are designed based on the micro-coaxial structure, and each circuit is coaxially connected based on its own inner conductor to realize signal transmission and processing. In this case, compared with the traditional microstrip line structure, the isolation between each circuit can be higher based on the micro-coaxial structure, reducing mutual interference. At the same time, the performance of the micro-coaxial structure is not affected by bending and cross-coupling, which is convenient for constructing complex circuits and devices, thereby realizing a high degree of integration of the circuit system; in addition, the coaxial connection of each circuit can facilitate the integration of the circuit and is easy to connect, thereby making the volume of the terahertz micro-coaxial integrated front end smaller, thereby reducing the loss of the overall circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. It is obvious that the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

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

[0019] Figure 2 is a schematic structural diagram of a rectangular micro-coaxial line according to an embodiment of the present application;

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

[0021] Figure 4 It is a schematic structural diagram of the inner conductor of the terahertz micro-coaxial integrated front end of an embodiment of the present application;

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

[0023] Figure 6 It is a structural block diagram of a micro-coaxial local oscillator driven frequency multiplier according to an embodiment of the present application;

[0024] Figure 7 It is a structural schematic diagram of a micro-coaxial local oscillator driven frequency multiplier according to an embodiment of the present application;

[0025] Figure 8 It is a schematic diagram of the internal structure of the micro-coaxial local oscillator driven frequency multiplier of the embodiment of the present application;

[0026] Fig. 9 It is a schematic structural diagram of the inner conductor of the micro-coaxial local oscillator driven frequency multiplier in an embodiment of the present application;

[0027] Fig.10 It is a schematic diagram of the structure of the inner conductor of the micro-coaxial terahertz converter according to an embodiment of the present application.

[0028] In the figure: 1. Terahertz micro-coaxial integrated front end; 2. Micro-coaxial coupler; 3. Micro-coaxial local oscillator driven frequency multiplier; 4. Micro-coaxial terahertz frequency converter; 5. Micro-coaxial filter; 6. Micro-coaxial first transition waveguide; 7. Micro-coaxial second transition waveguide;

[0029] S1, receiving end of the local oscillator driven frequency multiplier of the micro-coaxial; S2, output end of the local oscillator driven frequency multiplier of the micro-coaxial; 30, inner conductor lead direct connection structure; 31, transition structure of the input waveguide of the micro-coaxial; 32, input waveguide; 33, input low-pass filter of the micro-coaxial; 34, diode pair; 35, transition structure of the output waveguide of the micro-coaxial; 36, micro-coaxial matching circuit; 37, output waveguide; 310, input probe; 350, output probe;

[0030] S3, receiving end of micro-coaxial coupler; S4, output end of micro-coaxial coupler; 20, transmission waveguide of micro-coaxial; 21, isolation waveguide of micro-coaxial; 22, branch structure of micro-coaxial;

[0031] S5, the first receiving end of the micro-coaxial terahertz converter; S6, the second receiving end of the micro-coaxial terahertz converter; S7, the output end of the micro-coaxial terahertz converter; 40, the local oscillator waveguide of the micro-coaxial; 41, the radio frequency waveguide of the micro-coaxial; 42, the rectangular micro-coaxial-SMA coaxial transition structure; 43, the local oscillator probe; 44, the local oscillator low-pass filter of the micro-coaxial; 45, the intermediate frequency low-pass filter of the micro-coaxial; 46, the diode; 47, the radio frequency probe. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present application clearer, the various exemplary embodiments to be described below will refer to the corresponding drawings, which constitute a part of the exemplary embodiments, wherein various exemplary embodiments that may be used to implement the present application are described. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation methods described in the following exemplary embodiments do not represent all implementation methods consistent with the present disclosure. It should be understood that they are only examples of processes, methods, and devices that are consistent with some aspects disclosed in the present application as detailed in the attached claims, and other embodiments may also be used, or the embodiments listed herein may be modified in structure and function without departing from the scope and essence of the present application.

[0033] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", etc. indicate the orientation or positional relationship based on the drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the elements referred to must have a specific orientation, be constructed and operated in a specific orientation. The terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. The term "multiple" means two or more. The terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a communication connection, a direct connection, an indirect connection 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 related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0034] In order to illustrate the technical solution described in the present application, a specific embodiment is provided below, and only the parts related to the embodiment of the present application are shown.

[0035] like Figure 1 As shown, the present application provides a terahertz micro-coaxial integrated front end 1, including a micro-coaxial local oscillator driven 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 driven frequency multiplier 3 can receive the original local oscillator signal, perform frequency multiplication processing on the original local oscillator signal, and obtain a frequency multiplied local oscillator signal; the micro-coaxial coupler 2 can be used to monitor the output power of the micro-coaxial local oscillator driven frequency multiplier 3, and transmit the frequency multiplied local oscillator signal to the micro-coaxial terahertz converter 4; the micro-coaxial terahertz converter 4 can receive the original radio frequency signal and the frequency multiplied local oscillator signal transmitted by the micro-coaxial coupler 2, perform frequency conversion processing on the frequency multiplied local oscillator signal and the original radio frequency signal, and obtain an intermediate frequency signal.

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

[0038] In some embodiments, the transmission mode of the rectangular micro-coaxial line is TEM mode. Therefore, the use of rectangular micro-coaxial line for transmission has the advantages of low dispersion and low loss, and can enable the terahertz micro-coaxial integrated front end 1 to operate at a wider operating frequency.

[0039] In summary, the traditional rectangular waveguide has high-pass characteristics. For a rectangular waveguide of fixed size, it can only transmit electromagnetic waves of a fixed frequency band and cannot transmit broadband. At the same time, because the inner conductor of the rectangular micro-coaxial line is closed and has high isolation, even if two rectangular micro-coaxial lines are very close to each other, their mutual interference is extremely small, so they can be wired very close to each other. By adjusting the size of the inner conductor, it is easy to change the impedance. In addition, the performance of the rectangular micro-coaxial line is not affected by bending and cross-coupling, which facilitates the construction of complex circuits and devices, thereby achieving a high degree of integration of the circuit system.

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

[0041] In some embodiments, Figure 1 , Figure 3 and Figure 4 As shown, the output end of the micro-coaxial local oscillator driven frequency multiplier 3 can be coaxially connected to the receiving end S3 of the micro-coaxial coupler 2, and the first receiving end S5 of the micro-coaxial terahertz converter 4 can be coaxially connected to the output end 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 micro-coaxial local oscillator-driven frequency multiplier 3 and transmit it to the micro-coaxial terahertz converter 4 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 driven frequency multiplier 3 can receive the original local oscillator signal, the output end S7 of the micro-coaxial terahertz converter 4 can output the intermediate frequency signal, and the second receiving end S6 of the micro-coaxial terahertz converter 4 can receive the original radio frequency signal.

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

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

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

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

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

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

[0050] In some embodiments, the micro-coaxial transmission waveguide 20 may be coaxially connected to the micro-coaxial isolation waveguide 21 through a plurality of micro-coaxial branch structures 22, and may be symmetrically arranged about the plurality of micro-coaxial branch structures 22. The plurality of micro-coaxial branch structures 22 may have a preset interval therebetween.

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

[0052] In some embodiments, the length of the micro-coaxial branch structure 22 may be equal to the interval between the micro-coaxial transmission waveguide 20 and the micro-coaxial isolation waveguide 21 .

[0053] In some embodiments, Figure 6 As shown, the local oscillator driven frequency multiplier 3 of the micro-coaxial device includes an inner conductor lead-out direct connection structure 30, a transition structure 31 of the micro-coaxial input waveguide, an input waveguide 32 for receiving an original local oscillator signal, a micro-coaxial input low-pass filter 33 for filtering the original local oscillator signal, a diode pair 34 for frequency-multiplying and amplifying the filtered original local oscillator signal to generate a frequency-doubled local oscillator signal, a transition structure 35 of the micro-coaxial output waveguide, two micro-coaxial 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, 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 micro-coaxial input waveguide. 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 led out from the inner conductor of the direct connection structure 30 through the SMA coaxial line to DC feed the micro-coaxial local oscillator drive multiplier 3. Since the DC bias can be directly loaded through the inner conductor, the volume can be reduced by 50% compared with the traditional multiplier. The SMA (SubMiniature version A) coaxial line is a radio frequency coaxial cable connector.

[0056] In the conventional frequency multiplier structure based on microstrip lines, since the substrate is often made of quartz substrate or other materials, the inner conductor of the coaxial connector cannot be directly connected to it, and an additional 5880 soft substrate transition needs to be set, which increases the volume of the circuit, the connection loss and the difficulty of overall processing. The inner conductor lead-out direct connection structure 30 of the embodiment of the present application can be formed by directly extending the rectangular micro-coaxial line, so the embodiment of the present application has the advantages of simple structure, convenient connection, low loss, small volume, etc.

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

[0058] In some embodiments, Figures 7 to 9 As shown, the first end of the transition structure 31 of the micro-coaxial 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 micro-coaxial input waveguide can be connected to the input waveguide 32, and the third end of the transition structure 31 of the micro-coaxial input waveguide can be coaxially connected to the micro-coaxial input low-pass filter 33. The inner conductor of the transition structure 31 of the micro-coaxial 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 micro-coaxial input waveguide can be directly connected to the inner conductor of the micro-coaxial input low-pass filter 33.

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

[0060] In some embodiments, the transition structure 31 of the micro-coaxial input waveguide may include an input probe 310, which may be formed by extending the inner conductor of the transition structure 31 of the micro-coaxial input waveguide to the inside of the input waveguide 32, and is used for impedance matching between the transition structure 31 of the micro-coaxial input waveguide and the input waveguide 32. In the embodiment of the present application, when the transition structure 31 of the micro-coaxial input waveguide transitions to the input waveguide 32, it is only necessary to extend the inner conductor outward, so 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 driven multiplier 3, and 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 a plurality of rectangular branches. Specifically, the inner conductor of the micro-coaxial input low-pass filter 33 may extend in a direction perpendicular to the extension direction of the inner conductor to form a plurality of rectangular branches. Thus, the impedance can be changed, thereby achieving the performance of the resonant cavity and satisfying the filtering effect.

[0064] Compared with a microstrip line filter, the structure of the micro-coaxial input low-pass filter 33 can reduce the lateral length of the circuit and the overall size can be reduced by 20%.

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

[0066] In some embodiments, the diode pair 34 can be directly connected to the inner conductor of the micro-coaxial matching circuit 36 ​​at both ends of the 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 ​​the diode pair 34 can be increased, reducing the impact of heat accumulation on the performance of the terahertz frequency multiplier.

[0067] The traditional frequency multiplier diode integration method is mainly based on the flip-chip process, that is, the diode chip is separate and is bonded to the circuit substrate by artificial assembly using conductive adhesive and other materials. Therefore, in the traditional frequency multiplier, only a small part of the diode is connected to the external cavity. Since the external cavity is metal, the heat dissipation of the diode mainly depends on the heat conduction with the external cavity. Due to the small connection area with the metal, heat dissipation is difficult, and heat accumulation will further deteriorate the performance of the frequency multiplier.

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

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

[0070] In some embodiments, the transition structure 35 of the micro-coaxial output waveguide may include an output probe 350, which may be formed by extending the inner conductor of the transition structure 35 of the micro-coaxial output waveguide toward the inside of the output waveguide 37, for impedance matching between the transition structure 35 of the micro-coaxial output waveguide 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 a micro-coaxial arch matching structure; 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 micro-coaxial local oscillator driven multiplier 3.

[0072] In some embodiments, the micro-coaxial terahertz converter 4 may include a micro-coaxial local oscillator waveguide 40 for receiving a frequency-doubled local oscillator signal, a micro-coaxial radio frequency waveguide 41 for receiving an original radio frequency signal or a filtered radio frequency signal, and a rectangular micro-coaxial-SMA coaxial transition structure 42 for converting a rectangular waveguide structure into a circular structure. The micro-coaxial local oscillator waveguide 40 may be coaxially connected to both the micro-coaxial radio frequency waveguide 41 and the rectangular micro-coaxial-SMA coaxial transition structure 42. Since the micro-coaxial terahertz converter 4 of the embodiment of the present application does not adopt a substrate structure, multiple coaxial to microstrip line transitions are omitted, and the circuit structure of the entire micro-coaxial terahertz converter 4 is compact, and the volume can be reduced by 40% compared with the volume of a traditional converter, 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 converter 4, the first end of the micro-coaxial radio frequency waveguide 41 can be the second receiving end S6 of the micro-coaxial terahertz converter 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 converter 4.

[0074] In some embodiments, Fig.10 As shown, the micro-coaxial terahertz frequency converter 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 a radio frequency 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 the diode 46 can be coaxially connected to the second end of the micro-coaxial local oscillator low-pass filter 44, and the second end of the diode 46 can be coaxially connected to the first end of the RF probe 47, wherein the second end of the RF probe 47 can be coaxially connected to the second end of the micro-coaxial RF waveguide 41.

[0077] In some embodiments, the inner conductor of the local oscillator probe 43 may extend into the micro-coaxial local oscillator waveguide 40, and the inner conductor of the radio frequency probe 47 may extend into the micro-coaxial radio frequency waveguide 41. In this way, impedance matching can be performed.

[0078] In some embodiments, the micro-coaxial local oscillator low-pass filter 44 may be provided with rectangular branches, and the micro-coaxial local oscillator waveguide 40 may be a rectangular waveguide.

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

[0080] In some embodiments, the filtered RF signal or the original RF signal, and the frequency-doubled local oscillator signal can be fed into the corresponding rectangular waveguide ports respectively, loaded into the Schottky diode through their respective matching networks (RF matching circuit, local oscillator matching circuit) to participate in frequency conversion, and the generated 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 a plurality of rectangular branches.

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

[0083] In the present application, the local oscillator driven frequency multiplier 3, the micro-coaxial coupler 2 and the terahertz frequency converter 4 are designed based on the micro-coaxial structure, and each circuit is coaxially connected based on its own inner conductor to realize signal transmission and processing. In this case, compared with the traditional microstrip line structure, the isolation between each circuit can be higher based on the micro-coaxial structure, reducing mutual interference. At the same time, the performance of the micro-coaxial structure is not affected by bending and cross-coupling, which is convenient for constructing complex circuits and devices, thereby realizing a high degree of integration of the circuit system; in addition, the coaxial connection of each circuit can facilitate the integration of the circuit and is easy to connect, thereby making the volume of the terahertz micro-coaxial integrated front end 1 smaller, thereby reducing the loss of the overall circuit.

[0084] The above is only the preferred embodiment of the present application. Those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present application. In addition, under the guidance of the present application, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application belong to the protection scope of the present application.

Claims

1. A terahertz micro-coaxial integrated front end, characterized in that: It includes a micro-coaxial local oscillator driven frequency multiplier, a micro-coaxial coupler and a micro-coaxial terahertz frequency converter; the micro-coaxial local oscillator driven 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 to monitor the output power of the micro-coaxial local oscillator driven frequency multiplier, and transmits 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 a 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; The output end of the micro-coaxial local oscillator-driven frequency multiplier is coaxially connected to the receiving end of the micro-coaxial coupler, the first receiving end of the micro-coaxial terahertz frequency converter is coaxially connected to the output end of the micro-coaxial coupler, and the second receiving end of the micro-coaxial terahertz frequency converter receives the original radio frequency signal; The receiving end of the micro-coaxial local oscillator-driven frequency multiplier receives the original local oscillator signal, and the output end of the micro-coaxial terahertz frequency converter outputs the intermediate frequency signal.

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 micro-coaxial terahertz converter; the micro-coaxial filter receives the original radio frequency signal, filters the original radio frequency signal, and obtains a filtered radio frequency signal; the micro-coaxial terahertz converter 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 of the micro-coaxial and a second transition waveguide of the micro-coaxial; the first end of the first transition waveguide of the micro-coaxial is coaxially connected to the output end of the local oscillator driven frequency multiplier of the micro-coaxial, and the second end of the first transition waveguide of the micro-coaxial is coaxially connected to the receiving end of the micro-coaxial coupler; the first end of the second transition waveguide of the micro-coaxial is coaxially connected to the micro-coaxial filter, and the second end of the second transition waveguide of the micro-coaxial is coaxially connected to the second receiving end of the micro-coaxial terahertz converter.

4. The terahertz micro-coaxial integrated front end according to claim 1, characterized in that: The micro-coaxial coupler comprises a micro-coaxial transmission waveguide, a micro-coaxial isolation waveguide and a plurality of micro-coaxial branch structures; One end of the micro-coaxial transmission waveguide is the receiving end of the micro-coaxial coupler, and the other end of the micro-coaxial transmission waveguide is the output end of the micro-coaxial coupler; One end of the isolation waveguide of the micro-coaxial is a detection port, and the detection port couples part 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. The other end of the isolation waveguide of the micro-coaxial is an isolation port, and the isolation port is used to reduce internal electromagnetic interference. The transmission waveguide of the micro-coaxial and the isolation waveguide of the micro-coaxial are coaxially connected through the multiple micro-coaxial branch structures and are symmetrically arranged with respect to the multiple micro-coaxial branch structures. There are preset intervals between the multiple micro-coaxial branch structures.

5. The terahertz micro-coaxial integrated front end according to claim 1, characterized in that: The micro-coaxial local oscillator driven frequency multiplier includes an inner conductor lead-out direct connection structure, a transition structure of a micro-coaxial input waveguide, an input waveguide for receiving the original local oscillator signal, a micro-coaxial input low-pass filter for filtering the original local oscillator signal, a diode pair for frequency-multiplying and amplifying the filtered original local oscillator signal to generate the frequency-multiplied local oscillator signal, a transition structure of a micro-coaxial output waveguide, two micro-coaxial matching circuits, and an output waveguide for transmitting the frequency-multiplied 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 micro-coaxial, and 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, and 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 micro-coaxial input waveguide is coaxially connected to the second end of the inner conductor lead-out direct connection structure, the second end of the transition structure of the micro-coaxial input waveguide is connected to the input waveguide, and the third end of the transition structure of the micro-coaxial input waveguide is coaxially connected to the input low-pass filter of the micro-coaxial; The first end of the diode pair is coaxially connected to the input low-pass filter of the micro-coaxial through one of the micro-coaxial 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 micro-coaxial through another of the micro-coaxial matching circuits, wherein the second end of the transition structure of the output waveguide of the micro-coaxial 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 micro-coaxial input waveguide includes an input probe, which is formed by extending toward the inside of the input waveguide through the inner conductor of the transition structure of the micro-coaxial input waveguide, and is used for impedance matching between the transition structure of the micro-coaxial input waveguide and the input waveguide; The transition structure of the micro-coaxial output waveguide includes an output probe, which is formed by extending toward the inside of the output waveguide through an inner conductor of the transition structure of the micro-coaxial output waveguide, and is used for impedance matching between the transition structure of the micro-coaxial 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, 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; 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.

9. The terahertz micro-coaxial integrated front end according to claim 2, characterized in that: The micro-coaxial terahertz frequency converter comprises a micro-coaxial local oscillator waveguide for receiving the frequency-doubled 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 a rectangular waveguide structure into a circular structure, wherein the micro-coaxial local oscillator waveguide is coaxially connected to the micro-coaxial radio frequency waveguide and the rectangular micro-coaxial-SMA coaxial transition structure; The first end of the micro-coaxial local oscillator waveguide is the first receiving end of the micro-coaxial terahertz converter, the first end of the micro-coaxial radio frequency waveguide is the second receiving end of the micro-coaxial terahertz converter, and the first end of the rectangular micro-coaxial-SMA coaxial transition structure is the output end of the micro-coaxial terahertz converter.

10. The terahertz micro-coaxial integrated front end according to claim 9, characterized in that: The micro-coaxial terahertz frequency converter comprises a local oscillator probe, a micro-coaxial local oscillator low-pass filter, a micro-coaxial intermediate frequency low-pass filter, a diode for frequency conversion processing, and a radio frequency 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, 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, 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, wherein the second end of the intermediate frequency low-pass filter of the micro-coaxial 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, 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; The inner conductor of the local oscillator probe extends into the interior of the local oscillator waveguide of the micro-coaxial, and the inner conductor of the radio frequency probe extends into the interior of the radio frequency waveguide of the micro-coaxial.

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