Design And Implementation Of The Ultra-wideband Receiver

This article has completed the research and design of an 0.1-40 GHz ultra-wideband receiver,introduced the design of the receiver,the performed indicator analysis and simulation budget for key indicators such as gain,dynamic range,local oscillator leakage and spurious suppression,and according to the performance index of the receiver,the receiver is divided into several modules,and the prototype is assembled after the modules passed the performance test.Since the receiving range of the receiver is close to 40 GHz and covers multiple frequency bands,this article compares and analyzes the advantages and disadvantages of different receiving systems according to the performance index requirements of the receiver,and after combining the availability of components and the assembly process of chips in different frequency bands,and considering the gain distribution of the receiving system,it is determined that the receiver adopts a superheterodyne receiving structure with segmented reception and multiple frequency conversion.In addition,the division of the receiving frequency band is designed,the number of frequency conversion and the selection of intermediate frequency in different frequency bands is determined,and the frequency conversion scheme and spurious suppression are analyzed around the specific performance of the mixer and the performance indicators of the receiver,frequency planning of the entire system is also finished.After that,this article divides the radio frequency module according to the receiver design scheme,and divides the receiver into Ka-band down-conversion channel,Ku-band receiving module,Ku-band mixing module,0.1-6GHz frequency conversion channel and local oscillator,and completes the performance index allocation and the design of the principle block diagram of each module.Ka-band down-conversion channel adopts a super-heterodyne structure with a single frequency conversion to convert the RF signal of 18-26 GHz to 3.5-14 GHz.The RF signal of 3.5-18 GHz and the intermediate frequency signal output by the Ka broadband down-conversion channel are filtered and amplified,and then the Ku-band receiving module down-convert the3.5-18 GHz signal to 2GHz;the 0.1-6GHz frequency conversion channel adopts a double-conversion superheterodyne structure,converts the 0.1-6GHz RF signal and the output signal of the Ku-band mixing module to the intermediate frequency output signal of 375 MHz and 140 MHz.The local oscillator is responsible for providing the local oscillator signal required for frequency conversion for the 0.1-6GHz conversion channel.After choosing amplifiers,switches,digital step attenuators,filters,frequency sources and mixers that meet the index requirements,the link budget is carried out for each module.In the end,this article completes the circuit design and performance testing of the RF modules,and assembles the prototype.The Ka-band down-conversion channel can provide a gain of more than 20 dB with a noise figure of no more than 6dB;the two receiving channels inside the Ku-band receiving module can provide gains of 6dB and25 dB or more,with a noise figure of less than 4.2dB;in the low-noise mode and the conventional mode,the gains of the 0.1-6GHz receiving channel are about 48 dB and30 dB,respectively,and the noise figures do not exceed 4dB and 13 dB,respectively.The receiver prototype can provide about 45 dB of gain.