A multi-channel low-noise integrated high-frequency head

Abstract

This invention relates to the field of radar RF front-end technology and discloses a multi-channel low-noise integrated high-frequency head, including a waveguide-coaxial converter, a local oscillator power divider circuit, and at least four sets of structurally identical RF receiving channels. The waveguide-coaxial converter converts the antenna waveguide signal into a microstrip signal and inputs it to the corresponding RF receiving channel. The local oscillator power divider circuit provides local oscillator signals to each set of RF receiving channels. Each set of RF receiving channels is provided with a limiter, a digitally controlled attenuator, a low-noise amplifier unit, a filter, a mixer, and a temperature-compensated attenuator connected in sequence. This invention simplifies circuit link design, optimizes RF port matching performance, improves inter-channel amplitude and phase consistency and gain stability, reduces system noise figure, improves signal receiving sensitivity and anti-jamming interference capability, and achieves miniaturization, high integration, and stable operation over a wide temperature range, meeting the high-precision tracking and guidance requirements of modern monopulse radar systems.

Description

Technical Field

[0001] This invention relates to the field of radar radio frequency front-end technology. Background Technology

[0002] With the continuous development of radar technology, in order to improve the accuracy of target detection and tracking and achieve high-precision measurement of target angles within a single pulse, the single-pulse angle measurement system is widely adopted. A typical implementation involves an antenna forming a symmetrically focused crossbeam using four horns or a multi-mode feed, and configuring a sum-difference network to perform vector addition and subtraction on the received signals in the four quadrants, simultaneously generating four independent received signals: sum (Σ), azimuth difference (ΔAz), elevation difference (ΔE1), and dual difference (ΔΔ). The sum signal is used for target detection and ranging; the azimuth and elevation difference signals reflect the target's angular deviation in the horizontal and vertical directions, respectively; and the dual difference signal is obtained by double-differentiation of the two difference signals, mainly used to suppress main lobe interference and improve angle measurement accuracy in complex electromagnetic environments. Under this application requirement, the multi-channel LNB integrated design technology, capable of simultaneously processing multiple signals, has become a core key technology for radar RF front-ends.

[0003] Over the past decade, the rapid development of semiconductor technology and monolithic microwave integrated circuit (MMIC) technology has driven the evolution of microwave and millimeter-wave devices towards integration and lightweight design. The LNB, as the radio frequency front-end module of a radar system, primarily amplifies, converts, filters, and transmits weak echo signals, transforming radio frequency signals into intermediate frequency signals suitable for subsequent processing. Its noise figure, inter-channel amplitude consistency, phase consistency, and temperature stability directly determine the radar system's receiving sensitivity, target detection capability, and tracking and guidance level.

[0004] In current multi-channel LNB designs, most adopt single-channel or three-channel receiving architectures, which are insufficient to meet the synchronous processing requirements of four-channel single-pulse pairing, azimuth difference, elevation difference, and double-difference signals. Existing three-channel receiving architectures suffer from complex overall structures, poor RF port matching performance, difficulty in ensuring amplitude and phase consistency between channels, and poor gain stability. Furthermore, their cumbersome internal PCB layout hinders device integration and miniaturization, making it difficult to meet the requirements of modern radar systems for high consistency, high sensitivity, and high integration in multi-channel receiving front-ends. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-channel low-noise integrated high-frequency head that effectively simplifies circuit link design, optimizes RF port matching performance, improves inter-channel amplitude and phase consistency and gain stability, reduces system noise figure, improves signal receiving sensitivity and anti-blocking interference capability, and achieves miniaturization, high integration and stable operation over a wide temperature range, which can meet the high-precision tracking and guidance requirements of modern monopulse radar systems.

[0006] To address the aforementioned technical problems, this invention provides a multi-channel low-noise integrated high-frequency head, comprising a waveguide-coaxial converter, a local oscillator power divider circuit, and at least four sets of identical RF receiving channels. The waveguide-coaxial converter converts the antenna waveguide signal into a microstrip signal and inputs it into the corresponding RF receiving channel. The local oscillator power divider circuit provides local oscillator signals to each set of RF receiving channels. Each set of RF receiving channels includes a limiter, a digitally controlled attenuator, a low-noise amplifier unit, a filter, a mixer, and a temperature-compensated attenuator connected in sequence.

[0007] The low-noise amplifier unit includes a first-stage low-noise amplifier, a fixed attenuator, and a second-stage low-noise amplifier. The fixed attenuator is connected in series between the first-stage and second-stage low-noise amplifiers to adjust the gain distribution, optimize linearity, increase the isolation between the preceding and following stages, and reduce reflections.

[0008] The waveguide-coaxial converter is a coaxial probe-type transition structure. The probe extends vertically into the rectangular waveguide and feeds in the signal at a distance of λg / 4 from the short-circuit end of the waveguide cavity. The left side of the probe has a thickened structure, and the right side of the probe has a flattened structure and is connected to the microstrip line.

[0009] The numerically controlled attenuator is set to a maximum attenuation state and a minimum attenuation state. The operating state of the numerically controlled attenuator is switched by an external gain control signal to realize the attenuation adjustment of the echo signal and the control of large signal echo.

[0010] The filter is a low-pass filter, located at the signal input of the mixer, which purifies the signal spectrum entering the mixer and suppresses out-of-band spurious signals and image frequencies.

[0011] Both the first-stage low-noise amplifier and the second-stage low-noise amplifier use gallium arsenide semiconductor low-noise amplifiers. The two amplifiers improve the noise figure and work together to achieve a preset linear gain output, thereby improving channel stability.

[0012] The local oscillator power divider circuit sequentially amplifies and divides the input local oscillator signal, and outputs the amplified local oscillator signal to the corresponding mixer to reduce mixer losses.

[0013] The limiter is located at the signal input end of the digitally controlled attenuator. The limiter restricts the input large signal to a preset power output, ensuring the normal operation of the subsequent low-noise amplifier.

[0014] The temperature-compensated attenuator is located at the signal output end of the mixer. The temperature-compensated attenuator compensates for the gain changes of the RF receiving channel under high and low temperature environments.

[0015] The radio frequency receiving channels are configured into four groups, corresponding to the pitch difference channel, azimuth difference channel, and dual difference channel, respectively. The four groups of channels and the antenna use compressed waveguides for signal transmission to achieve miniaturization. The overall circuit design adopts multi-chip micro-assembly technology to achieve integration.

[0016] Compared to existing technologies, this invention, in terms of radio frequency performance, effectively reduces the system noise figure and improves receiving sensitivity by setting up a two-stage low-noise amplification and linearization control circuit, combined with a limiting and digitally controlled attenuation unit. It also expands the dynamic range of the input signal and enhances the front-end's anti-jamming capability. By optimizing the waveguide-coaxial conversion structure, it reduces signal conversion loss and port VSWR, widens the operating bandwidth, and improves the RF port matching characteristics. Regarding channel consistency, it adopts a multi-channel standardized receiving link design, combined with a local oscillator power divider and temperature compensation unit, significantly improving amplitude and phase consistency between channels and enhancing gain stability, providing a high-precision signal processing foundation for single-pulse angle measurement. In terms of functional completeness, through a complete four-channel configuration, it can simultaneously receive and process four signals: Σ (sigma), azimuth difference (ΔAz), elevation difference (ΔE1), and double difference (ΔΔ), meeting the requirements of all-state single-pulse angle measurement and anti-interference applications. In terms of system integration, a highly integrated multi-chip micro-assembly process is adopted to achieve overall integrated design, which simplifies circuit links and internal layout, and achieves miniaturization and high integration. It can be directly installed on the back of the antenna to obtain the optimal system noise figure.

[0017] In summary, this invention comprehensively solves the defects of the existing technology and achieves a multi-channel high-frequency head working state with low noise, high consistency, high stability and high integration, which can better adapt to the modern radar system's requirements for improved detection accuracy, tracking stability and guidance capabilities.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0019] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0020] Figure 1 This is a connection diagram of at least one embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this invention. The embodiments can be combined with and referenced by each other without contradiction.

[0022] Example 1 like Figure 1 The multi-channel low-noise integrated high-frequency head shown includes a waveguide-coaxial converter, a local oscillator power divider circuit, and at least four sets of identical RF receiving channels.

[0023] The waveguide-coaxial converter converts the antenna waveguide signal into a microstrip signal and inputs it to the corresponding RF receiving channel. This setup can complete the transition from antenna waveguide transmission mode to circuit microstrip transmission mode, ensuring efficient signal access to the receiving link.

[0024] The local oscillator power distribution circuit provides local oscillator signals to each group of RF receiving channels. The same source local oscillator signal supply method can ensure that the phase reference between channels is consistent, providing a basic condition for the amplitude and phase consistency between channels.

[0025] Each RF receiving channel contains a limiter, a digitally controlled attenuator, a low-noise amplifier, a filter, a mixer, and a temperature-compensated attenuator connected in sequence.

[0026] The limiter is located at the very beginning of the RF receiving channel to clamp the high-power input signal, limiting the signal amplitude to a safe range and preventing damage to downstream sensitive devices from excessive power signals.

[0027] The digitally controlled attenuator is located next to the limiter and is used to controllably adjust the amplitude of the input signal to adapt to echo signals of different intensities and expand the dynamic range of the overall input signal.

[0028] The low-noise amplifier unit is connected between the digitally controlled attenuator and the filter to amplify weak echo signals with low noise, thereby improving the system's ability to receive weak signals and reducing the overall noise figure of the system.

[0029] The filter is connected between the low-noise amplifier unit and the mixer to filter out out-of-band interference and image frequency components, thereby improving the purity of the signal entering the mixer.

[0030] The mixer simultaneously receives the local oscillator signal from the local oscillator power divider circuit, which is used to perform difference frequency processing on the RF echo signal and the local oscillator signal to realize the down-conversion of the RF signal to the intermediate frequency signal.

[0031] The temperature-compensated attenuator is connected to the output of the mixer to compensate for the link gain shift caused by changes in ambient temperature and maintain the stability of the output signal amplitude.

[0032] Each group of RF receiving channels adopts a symmetrical layout, which can reduce channel performance deviations caused by differences in wiring and parasitic parameters, and improve the consistency of multi-channel operation.

[0033] This architecture employs a multi-channel parallel architecture and standardized links to construct a universal and scalable RF signal receiving and frequency conversion platform. It overcomes the limitations of traditional single-channel or fixed-channel structures, adapting to the configuration requirements of various radar systems. Functional components are cascaded sequentially according to signal flow, forming a complete link for signal protection, amplitude adjustment, low-noise amplification, filtering, down-conversion, and temperature compensation, enabling synchronous processing of multiple RF signals output from the antenna. This architecture optimizes RF port matching characteristics, simplifies overall link design, and improves inter-channel amplitude and phase consistency and gain stability. This gives the LNB (Low-Noise Block downconverter) the fundamental capabilities of low noise, high consistency, and high reliability, meeting the universal and integrated requirements of modern radar systems for RF front-ends.

[0034] Example 2 Based on Embodiment 1, the low-noise amplification unit includes a first-stage low-noise amplifier, a fixed attenuator, and a second-stage low-noise amplifier. The fixed attenuator is connected in series between the first-stage low-noise amplifier and the second-stage low-noise amplifier. The fixed attenuator can adjust the signal amplitude between stages, so that both amplifiers are kept in the linear operating range, avoiding gain compression caused by large signal input, and improving the link linearity and dynamic range.

[0035] The waveguide-coaxial converter features a coaxial probe-type transition structure. The probe extends vertically into the rectangular waveguide, feeding the signal at a distance of λg / 4 from the short-circuit end of the waveguide cavity. This feeding position corresponds to the region of maximum electric field intensity within the waveguide, which improves energy conversion efficiency, reduces insertion loss, and expands the operating bandwidth. The left side of the probe has a thickened structure to enhance mechanical strength and assembly stability, preventing displacement or detachment during use. The right side of the probe has a flattened structure connected to the microstrip line, reducing impedance abrupt changes in the transmission line and improving impedance matching between the waveguide and the microstrip.

[0036] The digitally controlled attenuator is set to maximum and minimum attenuation states. The operating state of the digitally controlled attenuator is switched by an external gain control signal. The dual-state control mode simplifies the driving logic, has a fast response speed, and can quickly complete the amplitude adjustment of strong and weak echo signals and large signal suppression.

[0037] The filter is a low-pass filter, located at the signal input of the mixer. It filters out image frequency interference before the signal enters the mixer, blocking image interference from entering the intermediate frequency passband and ensuring the signal-to-noise ratio of the output intermediate frequency signal.

[0038] Both the first-stage and second-stage low-noise amplifiers use gallium arsenide (GaAs) semiconductor low-noise amplifiers. GaAs devices have a lower noise figure and higher gain characteristics, which can significantly reduce system noise and improve the receiver sensitivity of the LNB. The two-stage amplifiers improve the noise figure and work together to achieve preset linear gain output, improve channel stability, and ensure that weak signals are effectively amplified while maintaining stable link gain and linear output.

[0039] Therefore, through a linearized design with a two-stage amplification and fixed attenuator, an optimized waveguide-coaxial conversion structure, dual-state digitally controlled attenuation, pre-filtering to suppress image interference, and the selection of gallium arsenide low-noise devices, the core indicators of the LNB are comprehensively improved from multiple dimensions, including noise performance, linearity, conversion efficiency, signal purity, and channel consistency. This ensures both high-sensitivity reception of weak signals and linear output when strong signals are input, while reducing signal conversion loss and improving port matching performance. It effectively overcomes the problems of poor amplitude and phase consistency, insufficient gain stability, high noise figure, and poor linearity in traditional multi-channel LNBs, enabling the LNB to maintain a high-precision, low-distortion, and highly stable working state even in complex signal environments, providing accurate and reliable amplitude and phase information for radar systems.

[0040] Example 3 Based on Embodiment 1, the local oscillator power divider circuit sequentially amplifies and divides the input local oscillator signal, and outputs the amplified local oscillator signal to the corresponding mixer. The amplification-then-division processing method ensures that each local oscillator signal has sufficient excitation amplitude, reduces the frequency conversion loss of the mixer, and improves the strength of the intermediate frequency output signal.

[0041] The limiter is located at the signal input end of the digitally controlled attenuator. The limiter restricts the large input signal to a preset power output. Through power clamping, it controls the input signal within the safe operating range of the subsequent devices, ensuring the continuous and stable operation of the subsequent low-noise amplifier and other sensitive devices.

[0042] The temperature-compensated attenuator is located at the signal output of the mixer. The temperature-compensated attenuator adaptively adjusts the attenuation amount according to the ambient temperature, directly compensating for the gain shift of the link in high and low temperature environments, so that the channel gain remains stable across the entire temperature range.

[0043] The radio frequency receiving channels are set to four groups, corresponding to the pitch difference channel, azimuth difference channel, and dual difference channel, respectively, fully covering all channel types required for radar monopulse angle measurement, and meeting the target azimuth and pitch angle tracking and positioning requirements; the four channels are arranged in a compressed waveguide form, which reduces the overall structural size, improves the isolation between channels, and improves the radio frequency port matching characteristics; the whole is integrated using multi-chip micro-assembly technology, which shortens the signal wiring length, reduces parasitic parameters, reduces product size, improves integration, and allows the LNB to be directly mounted on the back of the antenna.

[0044] By optimizing the local oscillator power divider, front-end limiting protection, full-temperature gain compensation, four-channel complete configuration, compressed waveguide layout, and highly integrated micro-assembly technology, the LNB's environmental adaptability, structural compactness, channel isolation, system compatibility, and installation convenience are comprehensively improved. It also effectively enhances mixing efficiency, improves the front-end's anti-jamming interference capability with the limiter, ensures stable performance across the entire temperature range with the temperature-compensated attenuator, and addresses the shortcomings of traditional three-channel structures, such as complexity, poor matching, and low isolation. The compressed waveguide and micro-assembly technology achieve miniaturization and high integration. This allows the LNB to achieve optimal performance in terms of noise figure, channel consistency, structural size, environmental adaptability, and integration. It can be directly mounted close to the antenna to obtain the best system noise figure, significantly improving the radar system's detection accuracy, tracking stability, and guidance capability, fully meeting the requirements of modern phased array radars for high-performance multi-channel RF front-ends.

[0045] Example 4 Based on the above embodiments, a four-channel design is adopted, which can amplify, filter, down-convert, and attenuate the four sum and difference RF signals from the echo antenna, and output the intermediate frequency (IF) signal to the echo IF amplifier. High-integration multi-chip micro-assembly technology is used to reduce the structural size, simplify the installation method with the antenna, and improve the system noise figure to 3dB. The limiter and digitally controlled attenuator are placed at the front end of the microwave mixer link to achieve autonomous adjustment of strong and weak signals, withstand a power of 10W (continuous wave), improve the anti-jamming interference capability of the RF front end, and increase the input signal range. In addition, the following specific design is adopted: 1. Integrated Design: The mature, highly integrated multi-chip micro-assembly technology simplifies circuit design, significantly reduces size while improving product performance, and ensures good link amplitude and phase consistency when applied to other channels.

[0046] 2. High Sensitivity Technology: The relationship between noise figure and sensitivity can be summarized as follows: the lower the noise figure, the higher the sensitivity of the tuner. A high-gain, low-noise-figure gallium arsenide (GaAs) semiconductor low-noise amplifier (LNA) is selected to build the circuit, ensuring good internal matching. High-gain devices often lack linearity; therefore, the design employs a two-stage amplification process, with a fixed attenuator added in between to control the device's operation in the linear region and leave a certain margin, avoiding gain compression caused by large signals.

[0047] 3. Multi-channel design: It adopts a four-channel design, with the sum, elevation, azimuth, and dual-differential networks using compressed waveguides. The waveguide-coaxial converter realizes the conversion of the antenna's four waveguides to the LNB microstrip circuit. Compared with the traditional three-channel link, it has two additional dual-differential channels, which solves the problems of RF port matching and channel isolation. The performance is more consistent, and the structure is smaller and more integrated. Therefore, it can be directly installed behind the antenna to obtain the best system noise figure.

[0048] 4. Waveguide coaxial adapter design: A coaxial probe-type transition structure is adopted. The size of the probe in the waveguide cavity is increased to reduce the high impedance characteristics of the waveguide, thereby reducing the sensitivity of impedance to frequency changes. Simulation results show that the insertion loss is small, the standing wave ratio is low, and there is sufficient operating bandwidth. The structure is simple and easy to manufacture. The good matching characteristics greatly reduce the loss in the signal conversion process.

[0049] The components used are shown in Table 1.

[0050] Table 1 Component List

[0051] The waveguide-to-probe converter is designed as a waveguide-to-probe structure. The probe extends perpendicularly into the rectangular waveguide from the waveguide wall, at a distance from the short-circuit end of the high-frequency waveguide cavity. Feeding in, It can be calculated using the following two formulas: ( (where λ is the wavelength of an electromagnetic wave in a vacuum), the waveguide cavity is hollow, therefore (Where 'a' is the long side of the rectangular waveguide). The excitation probe will generate waves at both the open and short-circuit ends of the high-frequency waveguide cavity. The function of the short-circuit end of the high-frequency waveguide cavity is to reflect the wave propagating along the short-circuit direction back to the open end. The left side of the probe is designed to be thicker to prevent the probe from slipping into the waveguide cavity, while the right side is flattened for connection with the microstrip line. Simulation in the HFSS environment shows that the converter has a wide passband range, with an insertion loss of less than 0.1 dB and a standing wave ratio of less than 1.4 within the required 2 GHz passband.

[0052] The limiter has a power handling capacity of 40dBm and a limiting level of less than 14dBm, limiting large signals to a signal power output of 14dBm to prevent strong signals from burning out downstream link devices.

[0053] The digitally controlled attenuator achieves dynamic range control of 20dB attenuation.

[0054] Two-stage low-noise amplifiers can amplify weak signals, reduce the system noise figure, and achieve a linear gain of 17dB for the output signal.

[0055] The filter effectively suppresses the image frequency. Assuming the frequency of the local oscillator signal is F... LO The intermediate frequency is F IF Then when the input frequency is F LO +F IF and F LO -F IF At any given time, an intermediate frequency (IF) of the same frequency will be generated. Let the useful signal among them be denoted as F. in The other signal is image frequency interference, denoted as F. im To prevent F im Mixing with the local oscillator, falling into the intermediate frequency band, affects the SNR of the useful signal. A low-pass filter is added before the echo signal enters the mixer.

[0056] The local oscillator signal is divided into four channels to provide amplified local oscillator signals. These signals are then amplified to a typical value before being output to the mixer, reducing mixer losses. This invention is not limited to power-dividing devices; all devices that implement reference signal splitting, such as couplers and T-junction power dividers, are considered to be within the scope of this invention.

[0057] Waveguide coaxial adapters are used to solve the problems of low loss, wide bandwidth, and miniaturization in waveguide-microstrip transitions. However, they are not limited to this type of waveguide coaxial adapter. All waveguide-microstrip signal conversion devices, such as other waveguide-microstrip converters and microstrip probe converters, are considered to be included within the scope of protection of this invention.

[0058] The digitally controlled attenuator is used for attenuation control of the echo signal. It is not limited to the analog gain attenuation of the example circuit. As long as attenuation control can achieve signal power control, it is considered to be included in the protection scope of this invention.

[0059] Those skilled in the art will understand that the above embodiments can be modified in form and detail in practical applications without departing from the spirit and scope of the invention.

Claims

1. A multi-channel low-noise integrated high-frequency head, characterized in that, It includes a waveguide-coaxial converter, a local oscillator power divider circuit, and at least four sets of identical radio frequency receiving channels; The waveguide-coaxial converter converts the antenna waveguide signal into a microstrip signal and inputs it into the corresponding RF receiving channel. The local oscillator power divider circuit provides the local oscillator signal to each group of RF receiving channels. Each group of RF receiving channels includes a limiter, a digitally controlled attenuator, a low-noise amplifier, a filter, a mixer, and a temperature-compensated attenuator connected in sequence.

2. The multi-channel low-noise integrated high-frequency head according to claim 1, characterized in that, The low-noise amplifier unit includes a first-stage low-noise amplifier, a fixed attenuator, and a second-stage low-noise amplifier. The fixed attenuator is connected in series between the first-stage and second-stage low-noise amplifiers to adjust the gain distribution, optimize linearity, increase the isolation between the preceding and following stages, and reduce reflections.

3. The multi-channel low-noise integrated high-frequency head according to claim 1, characterized in that, The waveguide-coaxial converter is a coaxial probe-type transition structure. The probe extends vertically into the rectangular waveguide and feeds in the signal at a distance of λg / 4 from the short-circuit end of the waveguide cavity. The left side of the probe has a thickened structure, and the right side of the probe has a flattened structure that is connected to the microstrip line.

4. The multi-channel low-noise integrated high-frequency head according to claim 1, characterized in that, The numerically controlled attenuator is set to a maximum attenuation state and a minimum attenuation state. The operating state of the numerically controlled attenuator is switched by an external gain control signal to realize the attenuation adjustment of the echo signal and the control of large signal echo.

5. The multi-channel low-noise integrated high-frequency head according to claim 1, characterized in that, The filter is a low-pass filter, located at the signal input of the mixer, which purifies the signal spectrum entering the mixer and suppresses out-of-band spurious signals and image frequencies.

6. The multi-channel low-noise integrated high-frequency head according to claim 2, characterized in that, Both the first-stage low-noise amplifier and the second-stage low-noise amplifier use gallium arsenide semiconductor low-noise amplifiers. The two amplifiers improve the noise figure and work together to achieve a preset linear gain output, thereby improving channel stability.

7. The multi-channel low-noise integrated high-frequency head according to claim 1, characterized in that, The local oscillator power divider circuit sequentially amplifies and divides the input local oscillator signal, and outputs the amplified local oscillator signal to the corresponding mixer to reduce mixer losses.

8. The multi-channel low-noise integrated high-frequency head according to claim 1, characterized in that, The limiter is located at the signal input end of the digitally controlled attenuator. The limiter restricts the input large signal to a preset power output, ensuring the normal operation of the subsequent low-noise amplifier.

9. The multi-channel low-noise integrated high-frequency head according to claim 1, characterized in that, The temperature-compensated attenuator is located at the signal output end of the mixer. The temperature-compensated attenuator compensates for the gain changes of the RF receiving channel under high and low temperature environments.

10. The multi-channel low-noise integrated high-frequency head according to claim 1, characterized in that, The radio frequency receiving channels are configured into four groups, corresponding to the pitch difference channel, azimuth difference channel, and dual difference channel, respectively. The four groups of channels and the antenna use compressed waveguides for signal transmission to achieve miniaturization. The overall circuit design adopts multi-chip micro-assembly technology to achieve integration.

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