Terahertz broadband multi-band mixing receiver

Abstract

The invention provides a terahertz broadband multi-band mixing receiver, and relates to the field of terahertz. The multi-path local oscillation frequency source is connected with the plurality of subharmonic mixers through a plurality of signal channels and outputs homologous and multi-path independent local oscillation signals, and each path of local oscillation signal is transmitted to one subharmonic mixer through one signal channel; one subharmonic mixer is connected with one antenna; and the calibration unit is respectively connected with the plurality of local oscillator frequency sources and the plurality of subharmonic mixers. According to the invention, a 110-1100GHz terahertz broadband frequency mixing receiver is realized, a plurality of frequency sources are not required to provide different local oscillator signals, the system volume is reduced, the same frequency source is not required to be used in turn, and accessories such as a coaxial line and a power line are not required to be repeatedly connected, so that rapid and stable broadband receiving is realized; the working bandwidth and the integration level of the terahertz trace gas detection system are improved, real-time receiving of broadband signals is achieved, and meanwhile the size and the cost of the system are reduced.

Description

Technical Field

[0001] The invention relates to the field of terahertz technology, in particular to a terahertz broadband multi-band mixing receiver. Background Art

[0002] Terahertz trace gas spectrum detection requires that the terahertz wave receiver has the largest possible working bandwidth under the premise of ensuring sufficient resolution. Due to the limitations of Schottky diode junction capacitance and parasitic parameters and the bandwidth limitations of matching circuits, most of the current terahertz mixer receivers are single-band, and one receiver can only receive terahertz signals in one frequency band, which cannot meet the performance requirements of qualitative and quantitative identification of a large number of different types of gases. The direct combination or simple splicing of multiple mixer receivers results in a large system, high cost, and poor consistency. It is difficult to achieve fast and stable broadband reception by using the same frequency source to work in time-sharing mode, and it is difficult to ensure the consistency of the output of the frequency source by using different frequency sources to work independently, resulting in the inability to maintain consistent performance of multiple receivers. . Summary of the invention

[0003] In view of the above problems, the present invention is proposed to provide a terahertz broadband multi-band mixing receiver that solves the above problems or partially solves the above problems.

[0004] A first aspect of an embodiment of the present invention provides a terahertz broadband multi-band mixing receiver, the terahertz broadband multi-band mixing receiver comprising:

[0005] Multiple local oscillator frequency sources, multiple subharmonic mixers, multiple antennas and a calibration unit;

[0006] The multiple local oscillator frequency sources are connected to the multiple subharmonic mixers through multiple signal channels, and output multiple independent local oscillator signals of the same source, and each local oscillator signal is transmitted to a subharmonic mixer through a signal channel;

[0007] A subharmonic mixer is connected to one of the antennas, each antenna receives a terahertz signal of a partial frequency band, and the frequency bands of the terahertz signals received by all antennas are added together to cover the entire frequency band of the terahertz signal;

[0008] The calibration unit is connected to the multiple local oscillator frequency sources and the multiple subharmonic mixers respectively, and is used to calibrate the local oscillator signal in each signal channel so that the phases of all local oscillator signals are the same.

[0009] Optionally, the multi-channel local oscillator frequency source includes: a 1:n low-jitter power divider;

[0010] The multiple local oscillator frequency sources generate n local oscillator signals through the 1:n low-jitter power divider, wherein the frequency band of each local oscillator signal is different from that of other local oscillator signals.

[0011] Optionally, the 1:n low-jitter power divider is a 1:6 low-jitter power divider;

[0012] The multi-channel local oscillator frequency source generates 6 local oscillator signals through the 1:6 low-jitter power divider, and the frequency bands of the 6 local oscillator signals are respectively: 9.16 - 14.17 GHz, 9.44 - 14.45 GHz, 10.83 - 13.75 GHz, 10.31 - 15.63 GHz, 10.41 - 15.63 GHz, 10.41 - 15.28 GHz.

[0013] Optionally, each of the multiple sub-harmonic mixers integrates an E-plane waveguide - microstrip transition;

[0014] The local oscillator signal injection of each sub-harmonic mixer uses a directional coupler.

[0015] 5. The terahertz broadband multi-band mixing receiver according to claim 3, wherein each of the multiple sub-harmonic mixers has a built-in frequency doubling circuit;

[0016] The frequency doubling circuit is used to double the frequency of the received local oscillator signal;

[0017] Each sub-harmonic mixer down-converts the frequency-doubled local oscillator signal and the terahertz signal from the corresponding antenna, and outputs the down-converted intermediate frequency signal.

[0018] Optionally, the multiple sub-harmonic mixers include: 6 sub-harmonic mixers;

[0019] The 6 sub-harmonic mixers respectively have built-in frequency doubling circuits of 6 times, 9 times, 12 times, 18 times, 27 times, and 39 times;

[0020] Among them, the sub-harmonic mixer with a built-in 6-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 9.16 - 14.17 GHz;

[0021] The sub-harmonic mixer with a built-in 9-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 9.44 - 14.45 GHz;

[0022] The sub-harmonic mixer with a built-in 12-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 10.83 - 13.75 GHz;

[0023] The sub-harmonic mixer with a built-in 18-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 10.31 - 15.63 GHz;

[0024] The sub-harmonic mixer with a built-in 27-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 10.41 - 15.63 GHz;

[0025] A sub-harmonic mixer with a built-in 36x frequency multiplier circuit multiplies the local oscillator signal in the range of 10.41 - 15.28 GHz by 36 times.

[0026] Optionally, each of the sub-harmonic mixers is connected to the corresponding antenna through a waveguide.

[0027] Optionally, the multiple antennas include: six antennas;

[0028] The six antennas respectively receive terahertz signals in the ranges of 110 - 170 GHz, 170 - 260 GHz, 260 - 330 GHz, 330 - 500 GHz, 500 - 750 GHz, and 750 - 1100 GHz;

[0029] Among them, the antenna receiving the terahertz signal in the range of 110 - 170 GHz is connected to the sub-harmonic mixer with a built-in 6x frequency multiplier circuit;

[0030] The antenna receiving the terahertz signal in the range of 170 - 260 GHz is connected to the sub-harmonic mixer with a built-in 9x frequency multiplier circuit;

[0031] The antenna receiving the terahertz signal in the range of 260 - 330 GHz is connected to the sub-harmonic mixer with a built-in 12x frequency multiplier circuit;

[0032] The antenna receiving the terahertz signal in the range of 330 - 500 GHz is connected to the sub-harmonic mixer with a built-in 18x frequency multiplier circuit;

[0033] The antenna receiving the terahertz signal in the range of 500 - 750 GHz is connected to the sub-harmonic mixer with a built-in 27x frequency multiplier circuit;

[0034] The antenna receiving the terahertz signal in the range of 750 - 1100 GHz is connected to the sub-harmonic mixer with a built-in 36x frequency multiplier circuit.

[0035] Optionally, the calibration unit is integrated with a sampling function and an arithmetic function;

[0036] The calibration unit uses the sampling function to sample the local oscillator signal injected into each sub-harmonic mixer to obtain the real-time sampling signals corresponding to the respective local oscillator signals;

[0037] The calibration unit uses the arithmetic function to perform arithmetic operations on the real-time sampling signals to obtain the real-time phases corresponding to the respective local oscillator signals;

[0038] The calibration unit receives the reference clock from the multi-channel local oscillator frequency source and controls the delay time of each signal channel based on the reference clock and the real-time phase to calibrate the local oscillator signals in each signal channel so that the phases of all local oscillator signals are the same.

[0039] Optionally, each of the signal channels is connected to each of the sub-harmonic mixers through a coaxial cable. By utilizing the deformation characteristics of the coaxial cable, all the sub-harmonic mixers are arranged in a regular polygon layout, and the vertical interconnection part is realized by using gold wire bonding + air coaxial structure;

[0040] When there are 6 signal channels connected to 6 sub-harmonic mixers through coaxial cables, the 6 signal channels are connected to the 6 sub-harmonic mixers through a coaxial structure with an adjacent direction interval of 60° in six directions, so that the 6 sub-harmonic mixers form a regular hexagon layout, and the vertical interconnection part adopts a gold wire bonding + air coaxial structure.

[0041] The terahertz broadband multi-band mixing receiver provided by the present invention includes: a multi-channel local oscillator frequency source, a plurality of sub-harmonic mixers, a plurality of antennas, and a calibration unit. The multi-channel local oscillator frequency source is connected to the plurality of sub-harmonic mixers through a plurality of signal channels, and outputs local oscillator signals that are homologous and multi-channel independent. Each local oscillator signal is transmitted to a sub-harmonic mixer through a signal channel.

[0042] A sub-harmonic mixer is connected to an antenna. Each antenna receives terahertz signals in a partial frequency band. The frequency bands of the terahertz signals received by all the antennas are added together to cover the entire frequency band of the terahertz signals; the calibration unit is respectively connected to the multi-channel local oscillator frequency source and the plurality of sub-harmonic mixers, and is used to calibrate the local oscillator signals in each signal channel so that the phases of all the local oscillator signals are the same.

[0043] In the terahertz broadband multi-band mixing receiver proposed by the present invention, a plurality of sub-harmonic mixers are connected to antennas corresponding to frequency bands and are centrally packaged in the same cavity to realize miniaturization of the system end. Signals generated by the same frequency source are simultaneously output through a plurality of independent channels, and a plurality of local oscillator signals corresponding to frequency bands are generated through a plurality of coaxial cables and frequency doubling circuits with corresponding multiples.

[0044] A shared reference clock is introduced to calibrate the phases of each channel in real time. Coaxial structures in multiple directions are connected to a plurality of mixers based on three-dimensional stacking technology. The local oscillator signals generated based on this frequency source drive a plurality of sub-harmonic mixers to work simultaneously, realizing a terahertz broadband mixing receiver of 110~1100 GHz. It is no longer necessary to use multiple frequency sources to provide different local oscillator signals, reducing the system volume. It is also no longer necessary to alternately use the same frequency source and repeatedly connect accessories such as coaxial cables and power lines, realizing fast and stable broadband reception, improving the working bandwidth and integration of the terahertz trace gas detection system, realizing real-time reception of broadband signals, while reducing the system volume and cost, and having high practicability. Description of the Drawings

[0045] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0046] Figure 1 is a structural block diagram of a terahertz broadband multi-band mixing receiver according to an embodiment of the present invention;

[0047] Figure 2 is a schematic structural diagram of a preferred terahertz broadband multi-band mixing receiver of the present invention shown by taking 6 signal channels and 6 local oscillator signals as an example in an embodiment of the present invention. Specific Embodiments

[0048] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are only a part of the embodiments of the present invention, rather than all of the embodiments, and are not used to limit the present invention.

[0049] Terahertz waves are in the transition region between macroelectronics and microphotonics. Broadly speaking, they include electromagnetic waves in the frequency range of 0.1 - 10 THz, and are also called the "terahertz gap". It is of great significance in the detection and identification of chemical substances. The vibration and rotation energy levels of most gas molecules are in the terahertz band, so obvious characteristic peak absorptions will occur. By analyzing these characteristic frequencies, people can deeply understand their structures and properties, and provide accurate fingerprint spectrum information for detection and identification. To realize the real-time detection of the molecular states of reactants, intermediates and products during chemical reactions by terahertz waves, a terahertz trace gas detection and analysis system for real-time detection of chemical reaction experiments needs to be built.

[0050] A mixing receiver is an active detection system that receives radio frequency signals and mixes them with local oscillator signals and then down-converts them to intermediate frequencies. A terahertz mixing receiver can receive terahertz signals emitted or present in the atmospheric environment, and has characteristics such as high resolution, high response speed, and high sensitivity, and can provide absorption spectra of gas molecules in a gas cell or the atmospheric environment. Terahertz mixing reception technology can be widely applied in fields such as material detection and identification, high-speed communication, security inspection, and astronomical detection, and has great application prospects.

[0051] However, the inventor found that most of the currently studied terahertz mixing receivers are single-band. Limited by the mixing principle of Schottky diodes, a single receiver can only receive terahertz signals in one band. To realize the reception of ultra-wideband terahertz waves in the range of 110 - 1100 GHz, multiple mixing receivers need to work simultaneously.

[0052] The inventors further studied and found that the current solutions to the above problems are as follows: multiple frequency sources provide different local oscillator signals, and the entire system is very large in volume; or the same frequency source is used alternately, and it is necessary to repeatedly connect accessories such as coaxial cables and power lines, and adjust the transmitted signal of the frequency source, making it impossible to achieve fast and stable broadband reception.

[0053] However, the existing technical solutions using multiple independent frequency sources and mixing circuits result in an overly large system volume, which is not conducive to integration and miniaturization, and increases the system cost; using the same frequency source alternately requires repeated adjustment and connection, making it impossible to achieve fast and stable broadband reception. When existing multi-band receivers work simultaneously, due to the asynchronous phases of the local oscillator signals in different bands, interference occurs when the intermediate frequency signals are superimposed, reducing the detection signal-to-noise ratio.

[0054] Based on the above creative findings, after repeated research, the inventors creatively proposed a terahertz broadband multi-band mixing receiver of the present invention. The technical solutions of the present invention will be explained and described in detail below.

[0055] A terahertz broadband multi-band mixing receiver of the present invention, referring to Figure 1 the shown structural block diagram, includes: a multi-channel local oscillator frequency source, a plurality of sub-harmonic mixers, a plurality of antennas, and a calibration unit.

[0056] The multi-channel local oscillator frequency source is connected to a plurality of sub-harmonic mixers ( Figure 1 sub-harmonic mixers 1 to n in Figure 1 through a plurality of signal channels ( Figure 1 signal channels 1 to n in

[0057] ), and outputs local oscillator signals ( Figure 1 local oscillator signals 1 to n in

[0057] ) that are of the same source and multi-channel independent. Each local oscillator signal is transmitted to a sub-harmonic mixer through a signal channel.

[0058] One sub-harmonic mixer is connected to one antenna. Each antenna receives terahertz signals in part of the frequency bands. The frequency bands of the terahertz signals received by all antennas are added together to cover all the frequency bands of the terahertz signals; the calibration unit is respectively connected to the multi-channel local oscillator frequency source and the plurality of sub-harmonic mixers, and is used to calibrate the local oscillator signals in each signal channel so that the phases of all the local oscillator signals are the same.

[0059] In an embodiment of the present invention, preferably, each of the multiple sub-harmonic mixers integrates an E-plane waveguide - microstrip transition; a directional coupler is adopted for injecting the local oscillator signal of each sub-harmonic mixer.

[0060] In an embodiment of the present invention, preferably, each of the multiple sub-harmonic mixers is internally provided with a frequency doubling circuit; the frequency doubling circuit is used for doubling the received local oscillator signal; each sub-harmonic mixer down-converts the frequency-doubled local oscillator signal and the terahertz signal from the corresponding antenna, and outputs the down-converted intermediate frequency signal.

[0061] To better understand the terahertz broadband multi-band mixing receiver of the present invention, refer to Figure 2 the schematic structural diagram of a preferred terahertz broadband multi-band mixing receiver of the present invention shown with six signal channels and six local oscillator signals as an example.

[0062] The proposed 1:n low-jitter power divider is a 1:6 low-jitter power divider; six local oscillator frequency sources generate six local oscillator signals through the 1:6 low-jitter power divider, and the frequency bands of these six local oscillator signals are respectively: 9.16 - 14.17 GHz, 9.44 - 14.45 GHz, 10.83 - 13.75 GHz, 10.31 - 15.63 GHz, 10.41 - 15.63 GHz, 10.41 - 15.28 GHz.

[0063] The six local oscillator signals are respectively connected to six sub-harmonic mixers through six signal channels and six coaxial cables. The six sub-harmonic mixers are respectively internally provided with frequency doubling circuits of 6 times, 9 times, 12 times, 18 times, 27 times, and 39 times; among them, the sub-harmonic mixer internally provided with the 6-fold frequency doubling circuit doubles the local oscillator signal of 9.16 - 14.17 GHz ( Figure 2 represented by the 9.16 - 14.17 GHz sub-harmonic mixer in the text); the sub-harmonic mixer internally provided with the 9-fold frequency doubling circuit doubles the local oscillator signal of 9.44 - 14.45 GHz ( Figure 2 represented by the 9.44 - 14.45 GHz sub-harmonic mixer in the text); the sub-harmonic mixer internally provided with the 12-fold frequency doubling circuit doubles the local oscillator signal of 10.83 - 13.75 GHz ( Figure 2 represented by the 10.83 - 13.75 GHz sub-harmonic mixer in the text); the sub-harmonic mixer internally provided with the 18-fold frequency doubling circuit doubles the local oscillator signal of 10.31 - 15.63 GHz ( Figure 2 represented by the 10.31 - 15.63 GHz sub-harmonic mixer in the text); the sub-harmonic mixer internally provided with the 27-fold frequency doubling circuit doubles the local oscillator signal of 10.41 - 15.63 GHz ( Figure 2represented by a sub-harmonic mixer with a frequency range of 10.41 - 15.63 GHz; a sub-harmonic mixer with a built-in 36x frequency multiplier circuit multiplies the local oscillator signal in the range of 10.41 - 15.28 GHz by 36 Figure 2 represented by a sub-harmonic mixer with a frequency range of 10.41 - 15.28 GHz). Figure 2 In [it], "×6, ×9, ×12, ×18, ×27, ×36" are respectively used to represent the corresponding frequency multiplication.

[0064] In an embodiment of the present invention, preferably, each sub-harmonic mixer is connected to the corresponding antenna through a waveguide. Taking Figure 2 the 6 sub-harmonic mixers in [it] as an example, there are correspondingly 6 antennas, and the 6 antennas respectively receive terahertz signals in the ranges of 110 - 170 GHz, 170 - 260 GHz, 260 - 330 GHz, 330 - 500 GHz, 500 - 750 GHz, and 750 - 1100 GHz Figure 2 represented in [it] by an antenna for 110 - 170 GHz, an antenna for 170 - 260 GHz, an antenna for 260 - 330 GHz, an antenna for 330 - 500 GHz, an antenna for 500 - 750 GHz, and an antenna for 750 - 1100 GHz); among them, the antenna receiving the terahertz signal in the range of 110 - 170 GHz is connected to the sub-harmonic mixer with a built-in 6x frequency multiplier circuit; the antenna receiving the terahertz signal in the range of 170 - 260 GHz is connected to the sub-harmonic mixer with a built-in 9x frequency multiplier circuit; the antenna receiving the terahertz signal in the range of 260 - 330 GHz is connected to the sub-harmonic mixer with a built-in 12x frequency multiplier circuit; the antenna receiving the terahertz signal in the range of 330 - 500 GHz is connected to the sub-harmonic mixer with a built-in 18x frequency multiplier circuit; the antenna receiving the terahertz signal in the range of 500 - 750 GHz is connected to the sub-harmonic mixer with a built-in 27x frequency multiplier circuit; the antenna receiving the terahertz signal in the range of 750 - 1100 GHz is connected to the sub-harmonic mixer with a built-in 36x frequency multiplier circuit.

[0065] Each mixer down-converts the frequency-multiplied local oscillator signal and the terahertz signal from the corresponding antenna, and outputs the down-converted intermediate-frequency signal. For example: the sub-harmonic mixer with a built-in 6x frequency multiplier circuit multiplies the local oscillator signal in the range of 9.16 - 14.17 GHz by 6 to obtain a frequency-multiplied signal of 9.16×6 - 14.17×6, that is, a frequency-multiplied signal of 54.96 - 85.02 GHz, and then down-converts it with the terahertz signal in the range of 110 - 170 GHz, and finally outputs the down-converted intermediate-frequency signal.

[0066] In an embodiment of the present invention, the calibration unit integrates a sampling function and an arithmetic function; the calibration unit uses the sampling function to sample the local oscillator signals injected into each sub-harmonic mixer, and obtains real-time sampling signals corresponding to each local oscillator signal. For example, a high-speed ADC can be integrated in the calibration unit to sample in real time the local oscillator signals transmitted to the sub-harmonic mixer through each signal channel.

[0067] The calibration unit uses the arithmetic function to perform arithmetic operations on the real-time sampling signals, and obtains the real-time phases corresponding to each local oscillator signal. For example, the calibration unit can use a digital phase discriminator algorithm to perform arithmetic operations on the real-time sampling signals, and obtain the real-time phases corresponding to each local oscillator signal. For example: Figure 2 The real-time phases of 6 local oscillator signals.

[0068] The calibration unit receives the reference clock from a multi-channel local oscillator frequency source, and based on the reference clock and the real-time phase, controls the delay time of each signal channel to calibrate the local oscillator signals in each signal channel ( Figure 2 represented by the phase calibration signal in), so that the phases of all local oscillator signals are the same, and the phase unity of each channel is realized. For example, each signal channel integrates a programmable all-digital delay-locked loop, and its delay time (Δt) and the phase offset The relationship is: where f LO is the center frequency of the local oscillator signal (for example, the center frequency of the local oscillator signal in the range of 9.16 - 14.17 GHz is 11.66 GHz). For example, if the phase of a certain signal channel lags by π / 2 radians, the delay time Δt = (π / 2) / (2π×10 GHz) = 21.44 ps needs to be increased. The delay line is dynamically adjusted through the PID control algorithm until the real-time phases of all signal channels are synchronized with the reference clock

[0069] In an embodiment of the present invention, each signal channel is connected to each sub-harmonic mixer through a coaxial cable. Using the deformation characteristics of the coaxial cable, all sub-harmonic mixers are arranged in a regular polygon layout, and the vertical interconnection part is realized by gold wire bonding + air coaxial structure.

[0070] For example: when 6 signal channels are connected to 6 sub-harmonic mixers through coaxial cables, the coaxial structures of the 6 signal channels in six directions with an adjacent direction interval of 60° are connected to the 6 sub-harmonic mixers, so that the 6 sub-harmonic mixers form a regular hexagon layout, and the vertical interconnection part adopts a gold wire bonding + air coaxial structure. Such a layout can make the 6 sub-harmonic mixers form the densest regular hexagon layout, realizing the three-dimensional stacking miniaturization, stability and consistency of 6 signal channels.

[0071] The above Figure 2The shown terahertz broadband multi-band mixing receiver can be used as the receiving end of a 110 - 1100 GHz terahertz wave solid-state frequency multiplication link. The terahertz wave is generated through the frequency multiplication link. After passing through the gas cell, the terahertz wave carrying gas information is received by the antenna of the terahertz broadband multi-band mixing receiver proposed by the present invention, and is down-converted by the sub-harmonic mixer. The down-converted intermediate-frequency signal is output to a spectrum analyzer or an industrial control computer with a data acquisition card to realize the detection of trace gas broadband terahertz wave spectra. Similarly, the terahertz broadband multi-band mixing receiver proposed by the present invention can be used as a passive broadband detection system for terahertz waves to detect terahertz wave signals in the 110 - 1100 GHz frequency band existing in the atmospheric space or material radiation. While realizing 110 - 1100 GHz terahertz broadband mixing reception, the working bandwidth and integration degree of the terahertz trace gas detection system are also improved.

[0072] Through the above embodiments, the terahertz broadband multi-band mixing receiver provided by the present invention includes: multiple local oscillator frequency sources, multiple sub-harmonic mixers, multiple antennas, and a calibration unit. The multiple local oscillator frequency sources are connected to the multiple sub-harmonic mixers through multiple signal channels, and output local oscillator signals that are of the same source and are multiplexed and independent. Each local oscillator signal is transmitted to a sub-harmonic mixer through a signal channel.

[0073] A sub-harmonic mixer is connected to an antenna. Each antenna receives terahertz signals in a partial frequency band. The frequency bands of the terahertz signals received by all antennas are added together to cover the entire frequency band of the terahertz signals. The calibration unit is respectively connected to the multiple local oscillator frequency sources and the multiple sub-harmonic mixers, and is used to calibrate the local oscillator signals in each signal channel so that the phases of all local oscillator signals are the same.

[0074] For the terahertz broadband multi-band mixing receiver proposed by the present invention, multiple sub-harmonic mixers are connected to the antennas corresponding to their frequency bands and are centrally packaged in the same cavity to realize miniaturization at the end of the system. Signals generated by the same frequency source are simultaneously output through multiple independent channels, and multiple local oscillator signals corresponding to the frequency bands are generated through multiple coaxial cables and frequency multiplication circuits with corresponding multiples.

[0075] A shared reference clock is introduced to calibrate the phases of each channel in real time. Coaxial structures in multiple directions based on three-dimensional stacking technology are connected to multiple mixers. The local oscillator signals generated based on this frequency source drive multiple sub-harmonic mixers to work simultaneously, realizing a 110 - 1100 GHz terahertz broadband mixing receiver. There is no longer a need for multiple frequency sources to provide different local oscillator signals, reducing the system volume. Nor is it necessary to alternately use the same frequency source and repeatedly connect accessories such as coaxial cables and power supply lines, realizing fast and stable broadband reception, improving the working bandwidth and integration degree of the terahertz trace gas detection system, realizing real-time reception of broadband signals, while reducing the system volume and cost, and having high practicability.

[0076] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or terminal device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising said element.

[0077] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the purpose of the present invention and the scope protected by the claims. All of these are within the protection scope of the present invention.

Claims

1. A terahertz broadband multi-band mixing receiver, characterized in that, The terahertz broadband multi-band mixing receiver includes: a multi-channel local oscillator frequency source, a plurality of sub-harmonic mixers, a plurality of antennas, and a calibration unit; The multi-channel local oscillator frequency source is connected to the plurality of sub-harmonic mixers through a plurality of signal channels, and outputs a homologous and multi-channel independent local oscillator signal. Each local oscillator signal is transmitted to a sub-harmonic mixer through a signal channel; One sub-harmonic mixer is connected to one of the antennas. Each antenna receives terahertz signals in a partial frequency band, and the frequency bands of the terahertz signals received by all antennas are added together to cover the entire frequency band of the terahertz signals; The calibration unit is respectively connected to the multi-channel local oscillator frequency source and the plurality of sub-harmonic mixers, and is used to calibrate the local oscillator signals in each signal channel so that the phases of all local oscillator signals are the same.

2. The terahertz broadband multi-band mixing receiver according to claim 1, characterized in that, The multi-channel local oscillator frequency source includes: a 1:n low-jitter power divider; The multi-channel local oscillator frequency source generates n local oscillator signals through the 1:n low-jitter power divider, wherein the frequency band of each local oscillator signal is different from that of other channels.

3. The terahertz broadband multi-band mixing receiver according to claim 2, wherein The 1:n low-jitter power divider is a 1:6 low-jitter power divider; The multi-channel local oscillator frequency source generates 6 local oscillator signals through the 1:6 low-jitter power divider, and the frequency bands of the 6 local oscillator signals are respectively: 9.16 - 14.17 GHz, 9.44 - 14.45 GHz, 10.83 - 13.75 GHz, 10.31 - 15.63 GHz, 10.41 - 15.63 GHz, 10.41 - 15.28 GHz.

4. The terahertz broadband multi-band mixing receiver according to claim 1, characterized in that, Each of the plurality of sub-harmonic mixers integrates an E-plane waveguide - microstrip transition; The local oscillator signal injection of each sub-harmonic mixer uses a directional coupler.

5. The terahertz broadband multi-band mixing receiver according to claim 3, characterized in that Each of the plurality of sub-harmonic mixers has a built-in frequency doubling circuit; The frequency doubling circuit is used to double the frequency of the received local oscillator signal; Each sub-harmonic mixer down-converts the frequency-doubled local oscillator signal and the terahertz signal from the corresponding antenna, and outputs the down-converted intermediate frequency signal.

6. The terahertz broadband multi-band mixing receiver according to claim 5, characterized in that, The plurality of sub-harmonic mixers includes: 6 sub-harmonic mixers; The 6 sub-harmonic mixers respectively have built-in frequency doubling circuits of 6 times, 9 times, 12 times, 18 times, 27 times, and 39 times; Among them, the sub-harmonic mixer with a built-in 6-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 9.16 - 14.17 GHz; The sub-harmonic mixer with a built-in 9-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 9.44 - 14.45 GHz; The sub-harmonic mixer with a built-in 12-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 10.83 - 13.75 GHz; The sub-harmonic mixer with a built-in 18-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 10.31 - 15.63 GHz; The sub-harmonic mixer with a built-in 27-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 10.41 - 15.63 GHz; The sub-harmonic mixer with a built-in 36-fold frequency doubling circuit doubles the frequency of the local oscillator signal of 10.41 - 15.28 GHz.

7. The terahertz broadband multi-band mixing receiver according to claim 1, characterized in that Each of the sub-harmonic mixers is connected to the corresponding antenna through a waveguide.

8. The terahertz broadband multi-band mixing receiver according to claim 6, wherein The multiple antennas include: 6 antennas; The 6 antennas respectively receive terahertz signals of 110 - 170 GHz, 170 - 260 GHz, 260 - 330 GHz, 330 - 500 GHz, 500 - 750 GHz, and 750 - 1100 GHz; Among them, the antenna that receives the terahertz signal of 110 - 170 GHz is connected to a sub - harmonic mixer with a built - in 6 - times frequency - multiplier circuit; The antenna that receives the terahertz signal of 170 - 260 GHz is connected to a sub - harmonic mixer with a built - in 9 - times frequency - multiplier circuit; The antenna that receives the terahertz signal of 260 - 330 GHz is connected to a sub - harmonic mixer with a built - in 12 - times frequency - multiplier circuit; The antenna that receives the terahertz signal of 330 - 500 GHz is connected to a sub - harmonic mixer with a built - in 18 - times frequency - multiplier circuit; The antenna that receives the terahertz signal of 500 - 750 GHz is connected to a sub - harmonic mixer with a built - in 27 - times frequency - multiplier circuit; The antenna that receives the terahertz signal of 750 - 1100 GHz is connected to a sub - harmonic mixer with a built - in 36 - times frequency - multiplier circuit.

9. The terahertz broadband multi-band mixing receiver according to claim 1, wherein The calibration unit is integrated with a sampling function and an operation function; The calibration unit uses the sampling function to sample the local oscillator signals injected into each sub - harmonic mixer, and obtains real - time sampling signals corresponding to each local oscillator signal; The calibration unit uses the operation function to operate on the real - time sampling signals, and obtains real - time phases corresponding to each local oscillator signal; The calibration unit receives a reference clock from the multi - path local oscillator frequency source, and based on the reference clock and the real - time phase, controls the delay time of each signal channel to calibrate the local oscillator signals in each signal channel so that the phases of all local oscillator signals are the same.

10. The terahertz broadband multi-band mixing receiver according to claim 1, characterized in that, Each signal channel is connected to each sub - harmonic mixer through a coaxial cable. Using the deformation characteristics of the coaxial cable, all sub - harmonic mixers are arranged in a regular polygon layout, and the vertical interconnection part is realized by gold wire bonding + air coaxial structure; When 6 signal channels are connected to 6 sub - harmonic mixers through coaxial cables, the 6 signal channels are connected to the 6 sub - harmonic mixers in a coaxial structure with an interval of 60° between adjacent directions in six directions, so that the 6 sub - harmonic mixers form a regular hexagon layout, and the vertical interconnection part is realized by gold wire bonding + air coaxial structure.

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