Balanced 4n harmonic mixer structure based on double anti-parallel schottky diode pair and mixer

Abstract

The application discloses a balanced 4n harmonic mixing structure based on a double anti-parallel Schottky diode pair and a mixer, and belongs to the technical field of radio frequency, millimeter wave and terahertz harmonic mixing. The harmonic mixing structure comprises an RF input port, a local oscillator input port, an RF power division network, a local oscillator phase network, a first sub-harmonic mixing component, a second sub-harmonic mixing component and an intermediate frequency synthesis and extraction network; by adopting an anti-parallel Schottky diode pair in the first and second sub-harmonic mixing components, two groups of differential nonlinear current responses are respectively generated, the intermediate frequency synthesis and extraction network synthesizes the two groups of intermediate frequency responses according to I=(i1-i2)+(i3-i4), so that the mixing components with the local oscillator harmonic order of 4n are reserved, and the non-4n order mixing components are mutually cancelled. The intermediate frequency synthesis and extraction network can be realized through an in-cavity synthesis structure, an out-of-cavity intermediate frequency power synthesis structure or a coaxial output port post-stage synthesis structure. The application is suitable for millimeter wave and terahertz receiving, testing and communication equipment.

Description

Technical Field

[0001] This invention relates to the fields of radio frequency, millimeter wave and terahertz harmonic mixing technology, and in particular to a balanced 4n-th harmonic mixing structure, mixer and electronic device based on a pair of anti-parallel Schottky diodes, where n is a positive integer. Background Technology

[0002] Millimeter-wave and terahertz receiving, testing, and communication systems typically use mixers to convert high-frequency radio frequency (RF) signals into lower-frequency intermediate frequency (IF) signals. As the RF operating frequency increases, the frequency and output power of the local oscillator required for fundamental frequency mixing also increase, significantly increasing the design and implementation difficulty of the local oscillator frequency multiplier chain, port isolation structure, and waveguide packaging.

[0003] Harmonic mixers utilize the local oscillator harmonics generated by nonlinear devices to perform frequency conversion, thereby effectively reducing the fundamental operating frequency of the local oscillator. Anti-parallel Schottky diode pairs possess symmetrical nonlinear characteristics, making them suitable for high-order harmonic mixing; however, a single anti-parallel diode pair can simultaneously generate mixing components corresponding to multiple harmonics. Furthermore, in high-frequency waveguide packages, the layout and arrangement of the diode chip, RF feed lines, local oscillator feed lines, and intermediate frequency output ports directly affect amplitude and phase balance, port isolation, and spurious signal suppression capabilities. Summary of the Invention

[0004] The purpose of this invention is to address the problems of multi-order mixing component spurious emissions, port isolation, and amplitude-phase balance in the existing technology. It proposes a balanced 4n-th harmonic mixing structure and mixer based on a pair of anti-parallel Schottky diodes. Through the design concept of equal RF amplitude distribution, quadrature local oscillator feeding, and two-channel intermediate frequency synthesis, the 4n-th harmonic mixing components are selectively retained at the device level. This improves upon the shortcomings of traditional single-diode harmonic mixing spurious emissions suppression, achieving reduced local oscillator fundamental frequency requirements, suppression of non-4n-th harmonic spurious emissions, and compatibility with millimeter-wave and terahertz waveguide-planar hybrid integrated circuits.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A balanced 4n-th harmonic mixer structure based on a pair of anti-parallel Schottky diodes includes an RF input port, a local oscillator input port, an RF power divider network, a local oscillator phase network, a first subharmonic mixer component, a second subharmonic mixer component, and an intermediate frequency synthesis and extraction network.

[0007] The input terminal of the radio frequency power divider network is connected to the radio frequency input port, the first output terminal is connected to the radio frequency input port of the first subharmonic mixer component, and the second output terminal is connected to the radio frequency input port of the second subharmonic mixer component; it is used to receive externally provided radio frequency signals and divide the radio frequency signals into two equal-amplitude and in-phase radio frequency signals, which are respectively denoted as the first radio frequency signal and the second radio frequency signal.

[0008] The input terminal of the local oscillator phase network is connected to the local oscillator input port, the first output terminal is connected to the local oscillator input port of the first subharmonic mixer component, and the second output terminal is connected to the local oscillator input port of the second subharmonic mixer component; it is used to receive the local oscillator signal and divide the local oscillator signal into two local oscillator signals with equal amplitude and a phase difference of 90°, which are denoted as the first local oscillator signal and the second local oscillator signal, respectively.

[0009] The output port of the first subharmonic mixer component is connected to the first input port of the intermediate frequency synthesis and extraction network, and is used to receive the first radio frequency signal and the first local oscillator signal, and to perform mixing processing on the first radio frequency signal and the first local oscillator signal to generate the first intermediate frequency signal;

[0010] The output port of the second subharmonic mixer component is connected to the second input port of the intermediate frequency synthesis and extraction network, and is used to receive the second radio frequency signal and the second local oscillator signal, and to perform mixing processing on the second radio frequency signal and the second local oscillator signal to generate the second intermediate frequency signal;

[0011] The output of the intermediate frequency synthesis and extraction network is the final intermediate frequency output port, which is used to receive the first intermediate frequency signal and the second intermediate frequency signal, synthesize the first intermediate frequency signal and the second intermediate frequency signal in an in-phase superposition manner, and make the mixing outputs cancel each other out when k=4n+1, 4n+2 or 4n+3; where k is the local oscillator harmonic order and n is a positive integer; the synthesized intermediate frequency signal is output as the final intermediate frequency signal through the intermediate frequency output port.

[0012] Furthermore, the first subharmonic mixer component includes a first dielectric substrate, and a first radio frequency (RF) input waveguide, a first local oscillator (LO) input waveguide, a first anti-parallel Schottky diode pair, and a first intermediate frequency (IF) output port disposed on the first dielectric substrate; the first RF input waveguide is the RF input port of the first subharmonic mixer component; the first LO input waveguide is the LO input port of the first subharmonic mixer component; the first IF output port is the output port of the first subharmonic mixer component; the input terminals of the first anti-parallel Schottky diode pair are respectively connected to the first RF input waveguide and the first LO input waveguide, and the output terminals are connected to the first IF output port; it is used to generate a first current component i1 and a second current component i2 flowing through its two diodes according to the received first RF signal and the first LO signal; the first current component i1 and the second current component i2 are superimposed in the port loops at both ends of the first anti-parallel Schottky diode pair, and the difference frequency component is extracted to generate a first IF signal, which is then output from the first IF output port;

[0013] The second subharmonic mixer component includes a second dielectric substrate, and a second RF input waveguide, a second local oscillator input waveguide, a second anti-parallel Schottky diode pair, and a second intermediate frequency output port disposed on the second dielectric substrate; the second RF input waveguide is the RF input port of the second subharmonic mixer component; the second local oscillator input waveguide is the local oscillator input port of the second subharmonic mixer component; the input terminals of the second anti-parallel Schottky diode pair are respectively connected to the second RF input waveguide and the second local oscillator input waveguide, and the output terminals are connected to the second intermediate frequency output port; it is used to generate a third current component i3 and a fourth current component i4 flowing through its two diodes according to the received second RF signal and second local oscillator signal; after the third current component i3 and the fourth current component i4 are superimposed in the port loops at both ends of its diode pair, the difference frequency component is extracted to generate a second intermediate frequency signal and output from the second intermediate frequency output port.

[0014] Furthermore, the RF power divider network 120 adopts a waveguide T-type power divider structure, an E-plane power divider structure, an H-plane power divider structure, a suspended microstrip power divider structure, or a 0° power divider network.

[0015] Furthermore, the local oscillator phase network includes a 90° bridge and a local oscillator load port; the 90° bridge has a local oscillator input terminal, an isolation terminal, a first quadrature output terminal, and a second quadrature output terminal; the local oscillator input terminal of the 90° bridge is connected to the local oscillator input port, the isolation terminal is connected to the local oscillator load port, the first quadrature output terminal is connected to the first local oscillator input waveguide, and the second quadrature output terminal is connected to the second local oscillator input waveguide.

[0016] Furthermore, both the first anti-parallel Schottky diode pair and the second anti-parallel Schottky diode pair are composed of two semiconductor diode chips; the semiconductor diode chips are any one of gallium arsenide diode chips, indium phosphide diode chips, or silicon-based diode chips.

[0017] Furthermore, the first intermediate frequency output port is connected to the first input port of the intermediate frequency synthesis and extraction network through a first frequency microstrip transition section, and the second intermediate frequency output port is connected to the second input port of the intermediate frequency synthesis and extraction network through a second frequency microstrip transition section.

[0018] Furthermore, both the first and second intermediate frequency microstrip transition sections are polytetrafluoroethylene low-loss high-frequency dielectric substrates.

[0019] Furthermore, the balanced 4n-th harmonic mixing structure also includes a metal cavity, in which the first subharmonic mixing component and the second subharmonic mixing component are disposed and arranged parallel to each other about the central plane of the metal cavity.

[0020] Furthermore, the metal cavity is also provided with a first intermediate frequency coaxial output port and a second intermediate frequency coaxial output port; the intermediate frequency synthesis and extraction network is located inside or outside the metal cavity;

[0021] When the intermediate frequency synthesis and extraction network is located outside the metal cavity, its first input terminal is connected to the first intermediate frequency output port via the first intermediate frequency coaxial output port and the first intermediate frequency microstrip line, and its second input terminal is connected to the second intermediate frequency output port via the second intermediate frequency coaxial output port and the second intermediate frequency microstrip line.

[0022] A balanced 4n-th harmonic mixer, characterized in that it includes the above-mentioned balanced 4n-th harmonic mixing structure.

[0023] An electronic device, characterized in that it includes the above-mentioned balanced 4n-th harmonic mixer.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. This invention uses two sets of anti-parallel Schottky diode pairs to form a balanced mixing core, instead of four independent physical mixing paths, which helps to reduce the topological complexity of the device and makes the circuit structure consistent with the actual diode chip form.

[0026] 2. The RF power divider network provides equal-amplitude and in-phase RF excitation to the two sets of anti-parallel Schottky diode pairs, and the local oscillator phase network provides 90° quadrature local oscillator excitation to the two sets of anti-parallel Schottky diode pairs, so that a definite phase synthesis relationship is formed between the two sets of mixing responses.

[0027] 3. The intermediate frequency synthesis and extraction network synthesizes the two sets of intermediate frequency responses according to I=(i1-i2)+(i3-i4), so that the mixing component of the local oscillator harmonic order of 4n is retained, while the mixing components of the non-4n order local oscillator harmonics cancel each other out, thereby improving the selectivity of the target harmonic mixing component.

[0028] 4. The first dielectric substrate and the second dielectric substrate can use the same or mirrored planar mixer components, and cooperate with the dual RF input waveguide, dual local oscillator input waveguide and dual intermediate frequency output structure, which is beneficial to improve port isolation, amplitude and phase consistency and assembly symmetry.

[0029] 5. The intermediate frequency synthesis structure can be set inside the metal cavity, outside the metal cavity, or after the coaxial output port, and can be flexibly implemented according to the intermediate frequency, package space and system interface form. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall topology of the balanced 4n-th harmonic mixing structure according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the longitudinal structure of the first anti-parallel Schottky diode mixer component according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the radio frequency power divider network and two radio frequency input waveguides according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the local oscillator phase network, two local oscillator input waveguides, and two intermediate frequency output ports according to an embodiment of the present invention.

[0034] Figure 5 This is a schematic diagram of the packaging of a metal cavity, dual intermediate frequency microstrip transition section and dual intermediate frequency coaxial output port according to an embodiment of the present invention;

[0035] Figure label:

[0036] 110. RF input port, 120. RF power divider network, 130. Local oscillator input port, 140. Local oscillator phase network, 142. Local oscillator load port, 160. Intermediate frequency synthesis and extraction network, 170. Intermediate frequency output port, 220. First dielectric substrate, 221. First anti-parallel Schottky diode pair, 222. First intermediate frequency output port, 223. First local oscillator input waveguide, 224. First RF input waveguide, second RF input waveguide, 230. Second dielectric substrate, 231. Second parallel Schottky diode pair, 232. Second intermediate frequency output port, 233. Second local oscillator input waveguide, 225. First intermediate frequency coaxial output, 260. Metal cavity.

[0037] Specific implementation methods

[0038] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are used to explain the present invention and are not intended to limit the scope of protection of the present invention; where there is no conflict, the technical features of the various embodiments can be combined with each other.

[0039] like Figures 1 to 5 As shown, this embodiment provides a balanced 4n-th harmonic mixing structure based on a pair of anti-parallel Schottky diodes, including an RF input port 110, a local oscillator input port 130, an RF power divider network 120, a local oscillator phase network 140, a first subharmonic mixing component, a second subharmonic mixing component, and an intermediate frequency synthesis and extraction network 160.

[0040] like Figure 3 As shown, the input terminal of the RF power divider network 120 is connected to the RF input port 110, the first output terminal is connected to the RF input port of the first subharmonic mixer component, and the second output terminal is connected to the RF input port of the second subharmonic mixer component. It is used to receive externally provided RF signals and split the RF signals into two equal-amplitude, in-phase RF signals, denoted as the first RF signal and the second RF signal, respectively. The RF power divider network 120 can adopt a waveguide T-type power divider structure, an E-plane power divider structure, an H-plane power divider structure, a suspended microstrip power divider structure, or other power divider structures capable of providing equal-amplitude, in-phase output. In this embodiment, a 0° power divider network is selected.

[0041] like Figure 4 As shown, the input terminal of the local oscillator phase network 140 is connected to the local oscillator input port 130, the first output terminal is connected to the local oscillator input port of the first subharmonic mixer component, and the second output terminal is connected to the local oscillator input port of the second subharmonic mixer component. It is used to receive the local oscillator signal and split it into two local oscillator signals with equal amplitude and a 90° phase difference, denoted as the first local oscillator signal and the second local oscillator signal, respectively. In this embodiment, the local oscillator phase network consists of a 90° bridge 141 and a local oscillator load port 142. The 90° bridge 141 has a local oscillator input terminal, an isolation terminal, a first quadrature output terminal, and a second quadrature output terminal. The local oscillator input terminal of the 90° bridge 141 is connected to the local oscillator input port 130; the isolation terminal is connected to the local oscillator load port 142, used to absorb power from the isolation terminal and improve the local oscillator port matching; the first quadrature output terminal is connected to the first local oscillator input waveguide 223, and the second quadrature output terminal is connected to the second local oscillator input waveguide 233.

[0042] like Figure 2As shown, the output port of the first subharmonic mixer is connected to the first input port of the intermediate frequency synthesis and extraction network, and is used to receive the first radio frequency signal and the first local oscillator signal, and to perform mixing processing on the first radio frequency signal and the first local oscillator signal to generate the first intermediate frequency signal. The output port of the second subharmonic mixer is connected to the second input port of the intermediate frequency synthesis and extraction network, and is used to receive the second radio frequency signal and the second local oscillator signal, and to perform mixing processing on the second radio frequency signal and the second local oscillator signal to generate the second intermediate frequency signal. As the core components of the mixing structure in this embodiment, the specific structures of the first and second monolithic integrated harmonic mixers are as follows:

[0043] The first subharmonic mixer component includes a first dielectric substrate 220, and a first RF input waveguide 224, a first local oscillator input waveguide 223, a first anti-parallel Schottky diode pair 221, and a first intermediate frequency output port 222 disposed on the first dielectric substrate 220. The first RF input waveguide 224 is the RF input port of the first subharmonic mixer component; the first local oscillator input waveguide 223 is the local oscillator input port of the first subharmonic mixer component; the first intermediate frequency output port 222 is the output port of the first subharmonic mixer component; the input terminals of the first anti-parallel Schottky diode pair 221 are respectively connected to the first RF input waveguide 224. 4 and the first local oscillator input waveguide 223, the output end of which is connected to the first intermediate frequency output port 222; it is used to generate a first current component i1 and a second current component i2 flowing through its two diodes according to the received first radio frequency signal and the first local oscillator signal; the first current component i1 and the second current component i2 are superimposed in the port loops at both ends of the first anti-parallel Schottky diode pair, and the difference frequency component is extracted to generate the first intermediate frequency signal and output by the first intermediate frequency output port 222; the equivalent input corresponding to the first current component i1 is F(RF,LO), and the equivalent input corresponding to the second current component i2 is F(-RF,-LO).

[0044] The second subharmonic mixer component includes a second dielectric substrate 230, and a second RF input waveguide 234, a second local oscillator input waveguide 233, a second anti-parallel Schottky diode pair 231, and a second intermediate frequency output port 235 disposed on the second dielectric substrate 230. The second RF input waveguide 234 is the RF input port of the second subharmonic mixer component; the second local oscillator input waveguide 233 is the local oscillator input port of the second subharmonic mixer component; the input terminals of the second anti-parallel Schottky diode pair 231 are respectively connected to the second RF input waveguide 234 and the second local oscillator input waveguide 235. 33, the output terminal is connected to the second intermediate frequency output port 235; it is used to generate a third current component i3 and a fourth current component i4 flowing through its two diodes according to the received second radio frequency signal and second local oscillator signal; after the third current component i3 and the fourth current component i4 are superimposed in the port loops at both ends of its diode pair, the difference frequency component is extracted to generate the second intermediate frequency signal and output by the second intermediate frequency output port 235; the equivalent input corresponding to the third current component i3 is F(RF,-jLO), and the equivalent input corresponding to the fourth current component i4 is F(-RF,jLO).

[0045] In this embodiment, both the first and second anti-parallel Schottky diode pairs are composed of two Schottky diodes connected in parallel with opposite polarities; the Schottky diodes are semiconductor diode chips; the semiconductor diode chips are any one of gallium arsenide diode chips, indium phosphide diode chips, or silicon-based diode chips. It should be noted that i1 to i4 represent the nonlinear current components within the two anti-parallel Schottky diode pairs, rather than four independent physical mixing branches.

[0046] The output of the intermediate frequency synthesis and extraction network 160 is the final intermediate frequency output port 170, which is used to receive the first intermediate frequency signal and the second intermediate frequency signal, and synthesize the first intermediate frequency signal and the second intermediate frequency signal in an in-phase superposition manner. The synthesis operation relationship is as follows:

[0047] I = (i1 - i2) + (i3 - i4);

[0048] Among them, i1 and i2, i3 and i4 constitute differential signal pairs, and their sign difference reflects the 180° phase reversal introduced by the front-end balun or differential structure, thereby achieving the suppression of common-mode interference and the effective superposition of signals during the synthesis process.

[0049] To analyze the frequency selectivity of the network, the nonlinear response of the diode is expanded into a series with respect to the RF excitation order m and the local oscillator harmonic order k. Considering that the local oscillator signal generates two quadrature components after passing through the quadrature frequency divider network, which are then mixed with the RF signal, the synthesized output current can be uniformly expressed as:

[0050] RF m ·LO k ·[1-(-1) m (-1)^k+(-j) k -(-1) m ·j k ];

[0051] When the radio frequency signal takes the fundamental term, i.e., m=1, the synthesis coefficients in the above equation can be simplified to:

[0052] 1+(-1) k +(-j) k +j k ;

[0053] Further analysis of the coefficient's value characteristics under different local oscillator harmonic orders k; let n be any non-negative integer n=0,1,2,..., then we have:

[0054] When k=4n, the corresponding mixing term is retained, forming an effective intermediate frequency output;

[0055] When k = 4n+1, 4n+2 or 4n+3, the corresponding mixing terms completely cancel each other out due to the orthogonal superposition of phases.

[0056] It can be seen that the intermediate frequency synthesis network essentially achieves systematic suppression of the 4n+1, 4n+2 and 4n+3 components in the local oscillator harmonics, thereby effectively improving the spectral purity of the output intermediate frequency and reducing spurious interference.

[0057] Furthermore, the balanced 4n-th harmonic mixer structure of this embodiment also includes a metal cavity 260. The first and second subharmonic mixer components are disposed within the metal cavity and are arranged parallel to each other about the central plane of the metal cavity. The metal cavity is provided with a first intermediate frequency coaxial output port 225 and a second intermediate frequency coaxial output port 235. See details. Figure 5 :

[0058] The first intermediate frequency (IF) output port 222 on the first dielectric substrate 220 is connected to a first IF microstrip transition section, which in turn is connected to the first IF coaxial output port 225. The second IF output port 232 on the second dielectric substrate 230 is connected to the second IF coaxial output port 235 via the second IF microstrip transition section in the same or mirror manner. The IF microstrip transition section can be a low-loss, high-frequency dielectric substrate such as polytetrafluoroethylene (PTFE), for example, RT / duroid 5880, used to complete the electromagnetic transition and mechanical assembly between the planar transmission line of the dielectric substrate and the coaxial output structure. The first IF coaxial output port 225 and the second IF coaxial output port 235 are located on opposite sides, upper and lower sides, or other convenient assembly positions of the metal cavity 260, and are used to lead out the IF signals of the first IF output port 222 and the second IF output port 232, respectively. The first intermediate frequency output port 222, the second intermediate frequency output port 232, the intermediate frequency microstrip transition section, the first intermediate frequency coaxial output port 225, the second intermediate frequency coaxial output port 235, and the subsequent intermediate frequency synthesis structure together constitute an encapsulated implementation of the intermediate frequency synthesis and extraction network 160.

[0059] In one embodiment, the first intermediate frequency (IF) coaxial output port 225 and the second IF coaxial output port 235 are connected to an external IF power combining network outside the metal cavity 260. The two IF signals are combined into one IF signal by the external IF power combining network and output through the IF output port 170. In another embodiment, the IF combining structure can also be disposed inside the metal cavity 260, or disposed at the downstream connector or system interface of the first IF coaxial output port 225 and the second IF coaxial output port 235. Therefore, Figure 1 The intermediate frequency synthesis and extraction network 160 shown represents the extraction, transmission and synthesis functions of two intermediate frequency signals. Its specific implementation can be intracavity synthesis, extracavity synthesis or post-stage synthesis after coaxial output. It should not be understood as limited to independent planar devices set on the dielectric substrate.

[0060] Finally, it should be noted that the intermediate frequency microstrip transition section, coaxial output port, and external intermediate frequency power combining network provided in this embodiment are only one packaging implementation method and do not constitute a limitation on the packaging form. In other embodiments, the first intermediate frequency output port 222 and the second intermediate frequency output port 232 can also achieve intermediate frequency extraction and combining through other low-loss dielectric transition plates, planar transmission lines, conductive strips, bonding interconnects, connector transition structures, or intermediate frequency power combining networks integrated in a metal cavity; the positions of the two intermediate frequency output interfaces can also be changed according to the installation space, output frequency, and interface form.

[0061] The present invention also provides a balanced 4n harmonic mixer, which includes the balanced 4n harmonic mixing structure 100 described in any of the above embodiments. The balanced 4n harmonic mixer can receive the radio frequency signal under test through the radio frequency input port 110, receive the local oscillator signal through the local oscillator input port 130, and output the intermediate frequency signal after 4n harmonic mixing through the intermediate frequency output port 170.

[0062] The present invention also provides an electronic device comprising the aforementioned balanced 4n harmonic mixer. The electronic device may be a millimeter-wave receiver, a terahertz receiving front-end, a terahertz testing system, a spectrum analysis extension module, a communication receiving device, a radar receiving device, or other electronic devices requiring harmonic mixing functionality.

Claims

1. A balanced 4n-th harmonic mixer structure based on a pair of anti-parallel Schottky diodes, characterized in that, It includes an RF input port, a local oscillator input port, an RF power divider network, a local oscillator phase network, a first subharmonic mixer component, a second subharmonic mixer component, and an intermediate frequency synthesis and extraction network; The input terminal of the radio frequency power divider network is connected to the radio frequency input port, the first output terminal is connected to the radio frequency input port of the first subharmonic mixer component, and the second output terminal is connected to the radio frequency input port of the second subharmonic mixer component. It is used to receive externally provided radio frequency signals and split the radio frequency signals into two equal-amplitude and in-phase radio frequency signals, which are respectively referred to as the first radio frequency signal and the second radio frequency signal; The input terminal of the local oscillator phase network is connected to the local oscillator input port, the first output terminal is connected to the local oscillator input port of the first subharmonic mixer component, and the second output terminal is connected to the local oscillator input port of the second subharmonic mixer component; it is used to receive the local oscillator signal and divide the local oscillator signal into two local oscillator signals with equal amplitude and a phase difference of 90°, which are denoted as the first local oscillator signal and the second local oscillator signal, respectively. The output port of the first subharmonic mixer component is connected to the first input port of the intermediate frequency synthesis and extraction network, and is used to receive the first radio frequency signal and the first local oscillator signal, and to perform mixing processing on the first radio frequency signal and the first local oscillator signal to generate the first intermediate frequency signal; The output port of the second subharmonic mixer component is connected to the second input port of the intermediate frequency synthesis and extraction network, and is used to receive the second radio frequency signal and the second local oscillator signal, and to perform mixing processing on the second radio frequency signal and the second local oscillator signal to generate the second intermediate frequency signal; The output of the intermediate frequency synthesis and extraction network is the final intermediate frequency output port, which is used to receive the first intermediate frequency signal and the second intermediate frequency signal. The first intermediate frequency signal and the second intermediate frequency signal are synthesized in an in-phase superposition manner. For the first mixing term of the radio frequency signal, the corresponding mixing components cancel each other out or are suppressed when k=4n+1, 4n+2 or 4n+3; where k is the local oscillator harmonic order and n is a positive integer. When k=4n, the two intermediate frequency signals are coherently superimposed. The synthesized intermediate frequency signal is output as the final intermediate frequency signal through the intermediate frequency output port.

2. The balanced 4n-th harmonic mixing structure according to claim 1, characterized in that, The first subharmonic mixer component includes a first dielectric substrate, and a first radio frequency input waveguide, a first local oscillator input waveguide, a first anti-parallel Schottky diode pair, and a first intermediate frequency output port disposed on the first dielectric substrate; the first radio frequency input waveguide is the radio frequency input port of the first subharmonic mixer component; The first local oscillator input waveguide is the local oscillator input port of the first subharmonic mixer component; the first intermediate frequency output port is the output port of the first subharmonic mixer component; the input terminals of the first anti-parallel Schottky diode pair are respectively connected to the first radio frequency input waveguide and the first local oscillator input waveguide, and the output terminals are connected to the first intermediate frequency output port; It is used to generate a first current component i1 and a second current component i2 flowing through its two diodes according to the received first radio frequency signal and the first local oscillator signal; after the first current component i1 and the second current component i2 are superimposed in the port circuits at both ends of the first anti-parallel Schottky diode pair, the difference frequency component is extracted to generate a first intermediate frequency signal and output from the first intermediate frequency output port. The second subharmonic mixer component includes a second dielectric substrate, and a second RF input waveguide, a second local oscillator input waveguide, a second anti-parallel Schottky diode pair, and a second intermediate frequency output port disposed on the second dielectric substrate; the second RF input waveguide is the RF input port of the second subharmonic mixer component; the second local oscillator input waveguide is the local oscillator input port of the second subharmonic mixer component; the input terminals of the second anti-parallel Schottky diode pair are respectively connected to the second RF input waveguide and the second local oscillator input waveguide, and the output terminals are connected to the second intermediate frequency output port; It is used to generate a third current component i3 and a fourth current component i4 flowing through its two diodes according to the received second radio frequency signal and second local oscillator signal; after the third current component i3 and the fourth current component i4 are superimposed in the port loops at both ends of its diode pair, the difference frequency component is extracted to generate a second intermediate frequency signal and output from the second intermediate frequency output port.

3. The balanced 4n-th harmonic mixing structure according to claim 1, characterized in that, The RF power divider network 120 adopts a waveguide T-type power divider structure, an E-plane power divider structure, an H-plane power divider structure, a suspended microstrip power divider structure, or a 0° power divider network.

4. The balanced 4n-th harmonic mixing structure according to claim 2, characterized in that, The local oscillator phase network includes a 90° bridge and a local oscillator load port; the 90° bridge has a local oscillator input terminal, an isolation terminal, a first quadrature output terminal, and a second quadrature output terminal; the local oscillator input terminal of the 90° bridge is connected to the local oscillator input port, the isolation terminal is connected to the local oscillator load port, the first quadrature output terminal is connected to the first local oscillator input waveguide, and the second quadrature output terminal is connected to the second local oscillator input waveguide.

5. The balanced 4n-th harmonic mixing structure according to claim 2, characterized in that, The first anti-parallel Schottky diode pair and the second anti-parallel Schottky diode pair are each composed of two semiconductor diode chips; the semiconductor diode chips are any one of gallium arsenide diode chips, indium phosphide diode chips, or silicon-based diode chips.

6. The balanced 4n-th harmonic mixing structure according to claim 2, characterized in that, The first intermediate frequency output port is connected to the first input port of the intermediate frequency synthesis and extraction network through a first frequency microstrip transition section, and the second intermediate frequency output port is connected to the second input port of the intermediate frequency synthesis and extraction network through a second frequency microstrip transition section.

7. The balanced 4n-th harmonic mixing structure according to claim 6, characterized in that, Both the first and second intermediate frequency microstrip transition sections are polytetrafluoroethylene dielectric plates.

8. The balanced 4n-th harmonic mixing structure according to claim 7, characterized in that, The balanced 4n-th harmonic mixing structure further includes a metal cavity, in which the first subharmonic mixing component and the second subharmonic mixing component are disposed and arranged parallel to each other about the central plane of the metal cavity.

9. The balanced 4n-th harmonic mixing structure according to claim 8, characterized in that... The metal cavity is also provided with a first intermediate frequency coaxial output port and a second intermediate frequency coaxial output port; the intermediate frequency synthesis and extraction network is located inside or outside the metal cavity. When the intermediate frequency synthesis and extraction network is located outside the metal cavity, its first input terminal is connected to the first intermediate frequency output port via the first intermediate frequency coaxial output port and the first intermediate frequency microstrip line, and its second input terminal is connected to the second intermediate frequency output port via the second intermediate frequency coaxial output port and the second intermediate frequency microstrip line.

10. A balanced 4n-th harmonic mixer, characterized in that, This includes the aforementioned balanced 4n-th harmonic mixing structure.

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