Development Of 2 To 8 GHz Wideband Optional Pass Receiver Front-end

Modern and common communication standards required that the receiver must be compatible with different communications.Therefore,the research of high selectivity and low insertion loss multi-selective filter became a research hotspot.Multi-stage channelized parallel processing not only achieved the function of accurately processing data,but also could receive and process data quickly,which had been widely considered as the best broadband electronic warfare receiver among general receivers.Broadband channelized receiver systems were extremely complex and generally include multi-stage RF superheterodyne front-end systems and digital signal processing systems.As a universal channel receiver,it required a very good resolution,large dynamic range,high sensitivity,high linearity,high integration and other characteristics to ensure that the signal was small enough distortion and a bit error rate,as much as possible Improving the system's anti-interference ability,and its broadband features could also ensure sufficient confidentiality to meet the needs of military applications.In this paper,the first system development front-end channel selection multiplexer and low noise amplifier.The first level of the system required very low insertion loss and high isolation,which placed a high demand on channelized filters and low noise amplifiers.The article focused on the realization of these key components.First of all,based on the overall system of front-end indicators to locate the components of the index requirements,and then put forward the development plan.In this paper,A high-Q suspended microstrip line was used.With the high-low-pass filter cascade structure,a miniaturized multiplexer was designed using a stepped impedance and a serpentine structure,respectively,and a zigzag miniaturized transition wide microstrip line was realized to connect multiplexer.The main technical specifications include: the receiving frequency range: 2-8GHz,six channels received,the absolute bandwidth of each channel 1GHz,six channels respectively: 2-3GHz,3-4GHz,4-5GHz,5-6GHz,6-7GHz,7-8GHz,during which any one or more channels can be selected freely with the switch,and the bandwidth of the 63 different channels can be realized.With adaptive reception,the rectangular coefficient(-12.5dB/12.5dB)of the channel was 1.18,the isolation of the channel was greater than 20 dB,the gain was more than 13 dB,the gain fluctuation was within 1dB,the input return loss in the passband was greater than 12.5dB and thenoise coefficient was less than 8.5dB.In general,the desired development target is achieved,which fully embodies the selectable and high rectangular coefficients of the front-end multiplexer to meet the requirements of the vast majority of the communication receivers.At the end of the paper,as a follow-up work,we put forward the design scheme and modification suggestion of further narrowing the volume of the multi-channel selective filter.Finally,made a summaries and forecast about the work.