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CN-122026929-A - 210-220GHz radio frequency transmitting module

CN122026929ACN 122026929 ACN122026929 ACN 122026929ACN-122026929-A

Abstract

The invention relates to the field of wireless communication and discloses a 210-220GHz radio frequency transmitting module which comprises a case and a digital baseband processing unit, wherein the case comprises a local oscillator interface, an intermediate frequency interface, a radio frequency interface and a power supply interface, wherein the local oscillator interface is arranged inside the case and is used for introducing external reference or monitoring an internal clock state, the intermediate frequency interface is arranged inside the case and is used for receiving intermediate frequency signals, the radio frequency interface is arranged inside the case and is used for outputting radio frequency signals, the power supply interface is arranged on the outer wall of the case and is used for supplying power for the operation of an overall circuit, and the radio frequency circuit system is integrated inside the case. By adopting a three-dimensional stacked four-way synthesis topological structure in the power amplification unit and utilizing the space power synthesis technology in the waveguide cavity, the energy of the four-way solid power amplification tube core is overlapped in parallel, so that the effect of improving the radio frequency output power in the 210-220GHz terahertz frequency band is achieved.

Inventors

  • LU HAO
  • TAN ZHIZHONG
  • LV XINWEI

Assignees

  • 苏州泰莱微波技术有限公司

Dates

Publication Date
20260512
Application Date
20260205

Claims (10)

  1. 1. The 210-220GHz radio frequency transmitting module is characterized by comprising a case (1) and a digital baseband processing unit (20); The chassis (1) comprises: The local oscillation interface (2) is arranged inside the case (1) and is used for introducing external reference or monitoring the internal clock state; The intermediate frequency interface (3) is arranged inside the case (1) and is used for receiving intermediate frequency signals; The radio frequency interface (4) is arranged inside the case (1) and is used for outputting radio frequency signals; The power supply interface (5) is arranged on the outer wall of the chassis (1) and is used for supplying power to the whole circuit operation; the radio frequency circuit system integrated inside the chassis (1) comprises a local oscillator generating unit (11), a mixing unit (12) and a power amplifying unit (13) which are mutually cascaded; The local oscillation generating unit (11) is connected with the local oscillation interface (2) and is used for providing local oscillation signals; The intermediate frequency input end of the mixing unit (12) is connected to the intermediate frequency interface (3) and is used for performing mixing operation by utilizing the local oscillation signal and the intermediate frequency signal input through the intermediate frequency interface (3) and outputting a radio frequency signal; The power amplification unit (13) is connected to the radio frequency output end of the mixing unit (12), and the output end of the power amplification unit (13) is connected to the radio frequency interface (4); The digital baseband processing unit (20) stores therein frequency domain fingerprint data describing nonlinear characteristics of the radio frequency circuit system, and is used for performing amplitude and phase pre-correction processing on a baseband signal according to the frequency domain fingerprint data to generate a broadband driving signal sequence, and the broadband driving signal sequence is input to the intermediate frequency interface (3) after digital-to-analog conversion, so as to compensate frequency conversion loss fluctuation of the frequency mixing unit (12) and nonlinear distortion of the power amplifying unit (13).
  2. 2. A 210-220GHz radio frequency transmission module as claimed in claim 1, wherein the local oscillator generating unit (11) comprises: The phase-locked crystal oscillator is used for outputting a reference signal with the frequency of 100 MHz; The point frequency source is connected with the phase-locked crystal oscillator and is used for locking the reference signal by utilizing an internal phase-locked loop circuit and outputting a point frequency signal with the frequency of 13.125 GHz; And the frequency multiplier is connected with the point frequency source and is used for performing eight-time frequency processing on the point frequency signal of 13.125GHz and outputting the local oscillation signal with the frequency of 105GHz to the frequency mixing unit (12).
  3. 3. The 210-220GHz radio frequency transmission module as in claim 1 wherein, The frequency mixing unit (12) adopts an I/Q second harmonic mixer architecture, and the frequency of the radio frequency signal output by the frequency mixing unit covers 210GHz-220GHz; the power amplifying unit (13) adopts a three-dimensional stacked four-way synthesis topological structure, and four-way parallel solid power amplifying tube core energy is stacked in the waveguide cavity through a space power synthesis technology; The intermediate frequency interface (3) adopts an SMA female connector; The radio frequency interface (4) is configured as a waveguide flange of WR4.3-UG387/M specification.
  4. 4. The 210-220GHz radio frequency emission module as claimed in claim 1, wherein a heat dissipation assembly is arranged inside the chassis (1); The heat dissipation assembly comprises heat conduction glue, metal heat dissipation teeth and a case heat dissipation fan (6) arranged at the rear panel position of the case (1); The metal radiating teeth are adhered to the surfaces of the frequency multiplier and the power amplifying unit (13) through the heat conducting adhesive, and heat is conducted to the bottom plate of the chassis (1) through screw fixing holes; the chassis cooling fan (6) is matched with cooling holes formed in the side wall of the chassis (1) to form an air convection channel.
  5. 5. The 210-220GHz radio frequency transmission module of claim 1, wherein the digital baseband processing unit (20) comprises: A characteristic parameter storage subunit (21) for storing the frequency domain fingerprint data; A safety margin calculation subunit (22) for constructing a frequency-dependent maximum safety power envelope from the frequency domain fingerprint data and converting into a voltage amplitude limitation threshold; a pre-correction parameter generation subunit (23) for synthesizing the frequency domain fingerprint data and the voltage amplitude limitation threshold value, generating a complex predistortion filter comprising an amplitude pre-correction coefficient and a phase pre-correction response; -a real-time signal processing subunit (24) for applying said complex predistortion filter to a signal to be transmitted, generating said wideband drive signal sequence.
  6. 6. The 210-220GHz radio frequency transmission module of claim 5, wherein the frequency domain fingerprint data stored in the characteristic parameter storage subunit (21) comprises the following three sets of mapping relationship data with intermediate frequency as index key values: frequency conversion loss function data characterizing the power conversion efficiency of the mixing unit (12) at different frequencies, the values of which are distributed over a range of 10dB to 16 dB; -inputting saturation threshold function data characterizing an equivalent power threshold inversely translated to the intermediate frequency interface (3) based on a 1dB compression point output power of the power amplification unit (13); System group delay function data characterizing the total group delay profile of a signal transmitted from the digital baseband processing unit (20) output to the radio frequency interface (4).
  7. 7. The 210-220GHz radio frequency transmission module of claim 5, wherein the switching of the voltage amplitude limiting threshold comprises the steps of: For each frequency point in the working frequency band, calculating the difference value between the input saturation threshold function data and the linearity back-off allowance to obtain a dynamic linearity threshold; comparing the dynamic linear threshold value with a preset maximum allowable intermediate frequency input power constant, and selecting a smaller value of the dynamic linear threshold value and the preset maximum allowable intermediate frequency input power constant as a maximum safe power envelope surface of a frequency point; -converting the maximum safe power envelope into the voltage amplitude limiting threshold of a voltage domain based on a characteristic impedance of the intermediate frequency interface (3).
  8. 8. The 210-220GHz radio frequency transmission module of claim 5, wherein the generation of the amplitude pre-correction factor comprises the steps of: Calculating the product of the frequency conversion loss function data, a preset normalized gain constant and the frequency spectrum amplitude of a reference baseband signal aiming at each frequency point in the working frequency band to obtain a theoretical compensation driving voltage; Comparing the theoretical compensation driving voltage with a voltage amplitude limiting threshold value, and selecting the smaller value of the theoretical compensation driving voltage and the voltage amplitude limiting threshold value; And determining the amplitude pre-correction coefficient modulus value of the frequency point by using the ratio of the selected smaller value to the frequency spectrum amplitude of the reference baseband signal.
  9. 9. The 210-220GHz radio frequency transmission module of claim 5, wherein the generation of the phase pre-calibration response comprises the steps of: determining a target group delay constant, wherein the target group delay constant is the sum of the maximum value of system group delay function data in the full working bandwidth and causality allowance; And calculating a difference value of the system group delay function data corresponding to the target group delay constant and the frequency point aiming at each frequency point in the working frequency band, and carrying out frequency integration on the difference value to obtain a phase pre-correction angle of the frequency point.
  10. 10. The 210-220GHz radio frequency transmission module of claim 5, wherein the generation of the wideband drive signal sequence comprises the steps of: Converting the discrete time baseband signal sequence into a frequency domain complex sequence by using a fast Fourier transform logic core; reading the complex predistortion filter, and performing complex multiplication operation of frequency points with the frequency domain complex sequence to obtain a predistortion frequency spectrum; And restoring the predistortion spectrum into a time domain discrete signal by using an inverse fast Fourier transform logic core to generate the broadband driving signal sequence.

Description

210-220GHz radio frequency transmitting module Technical Field The invention relates to the technical field of wireless communication, in particular to a 210-220GHz radio frequency transmitting module. Background The 210-220GHz frequency band is positioned at the junction of millimeter waves and terahertz waves, and becomes an important working frequency band of the next-generation ultra-high-speed wireless communication and high-resolution imaging radar system because of extremely wide available frequency spectrum resources and good atmospheric transmission characteristics. The existing frequency band radio frequency transmitting module generally adopts a mixed integrated architecture based on a solid semiconductor technology, and an internal circuit of the existing frequency band radio frequency transmitting module is mostly formed by cascading a local oscillator frequency multiplication chain, an up-conversion mixer and a final power amplifier. In physical implementation, in order to reduce transmission loss and inhibit electromagnetic leakage, such a module generally uses a high-precision metal split cavity as a carrier, and an active chip made of gallium arsenide, indium phosphide or other materials is packaged in a waveguide channel through microstrip lines or probe transition. In order to realize the frequency spectrum shifting of signals, the traditional scheme is mostly dependent on a high-order frequency multiplier to generate a local oscillation signal in a terahertz frequency band to drive a mixer to work, the signal level is improved through a subsequent amplifying link, and finally energy is radiated outwards through a standard waveguide interface. However, with the increase of the operating frequency, the improvement of the hardware performance of the rf transmitting front end faces a serious physical bottleneck. In terms of power output capability, the saturated output power of the monolithic solid-state power amplifier is very limited due to the breakdown voltage and electron mobility limitation of the terahertz frequency band semiconductor material, and the requirement of a link budget for long-distance transmission is often difficult to meet. Although a technology for improving power through circuit synthesis exists at present, a traditional planar microstrip synthesis network can introduce huge dielectric loss and radiation loss in a frequency band above 200GHz, so that the synthesis efficiency is low, and a traditional waveguide synthesis structure is huge in size and narrow in bandwidth, so that the design requirements of compactness and broadband are difficult to be met. This means that existing transmit modules often have to be compromised in bandwidth or volume in pursuit of high power output. In addition, degradation of signal quality is also a critical factor limiting the performance of the frequency band communication system. Since 210-220GHz communication systems are generally required to support extremely wide intermediate frequency input bandwidths to achieve high-rate transmission, nonlinear devices such as mixers and power amplifiers exhibit drastic fluctuations in their amplitude-frequency response and phase-frequency response over such wide frequency bands. The frequency conversion loss of the mixer fluctuates with the frequency variation, which causes serious deterioration of the spectrum flatness of the output signal, and meanwhile, the nonlinear effect of the power amplifier under the drive of a large signal can cause in-band distortion and spectrum regeneration, thereby reducing the Error Vector Magnitude (EVM) index of the modulation signal. More troublesome is that the expensive power chip of terahertz frequency band is extremely sensitive to the driving level, and its saturation characteristic changes with frequency dynamics, and the current transmitting system generally lacks the fine pre-correction and dynamic safety protection mechanism to this kind of broadband nonlinear characteristic, has difficulty in fully excavating the linear working potential of hardware under the prerequisite of guaranteeing the device safety. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a 210-220GHz radio frequency transmitting module, which solves the problems that the output capability of the existing 210-220GHz radio frequency transmitting module is insufficient due to the limited power of a single-path solid-state device, and the spectrum flatness and linearity of a transmitting signal are poor and an expensive power device is easy to overdrive and damage due to the lack of a fine pre-correction and dynamic protection mechanism aiming at the nonlinear characteristics of broadband hardware. In order to achieve the above purpose, the invention is realized by the following technical scheme: The invention provides a 210-220GHz radio frequency transmitting module which comprises a case and a digital baseband processing unit. The chassis is used a