Research And Design Of 35GHz Dual-conversion Receiver Front-end

The Ka-band has a frequency range of 26.5 to 40 GHz and is a commonly used millimeter wave band for satellite communications and radar systems.It is also an important candidate for 5G communications.Research on the front-end of the Ka-band receiver is a hot topic in the current research of millimeter-wave circuits and systems,and has broad prospects.In this paper,based on the requirements of the subject,a 35 GHz double-conversion receiver front-end is studied and designed based on the hybrid integration method,and the physical production and index test are completed.The millimeter-wave receiver front-end designed this time is based on the superheterodyne receiver architecture.The receiving link is mainly composed of amplifiers,mixers,filters and other components.It is divided into three modules,which in turn realize preselection amplification,one-time conversion amplification,and double frequency conversion function.We carefully discussed the receiver front-end design scheme in this paper.The scheme requires that the receiver front-end can downconvert the 35 GHz RF signal to 30 MHz low-IF signal twice.Based on this,the feasibility analysis of the indicator allocation and link budget was made.The specific design uses sub-module design ideas,focusing on the basic principles and design methods of microstrip line,low noise amplifier,hairpin band-pass filter,balanced mixer,H-surface probe transition and other circuit structures.Combining the development status of domestic microwave monoliths,several well-performing amplifiers,mixer chips,and intermediate frequency filters were selected,and their structures and performances were analyzed.The author also studied the electromagnetic compatibility problem and the wire bonding technology in the front-end of the receiver.The circuit layout and the cavity structure were made with reference to the design scheme.The assembly of the three modules was completed using the hybrid integration method.Finally,the important indicators of the receiver front-end were tested,and the module tests were performed first.The results basically reached the expected goal.The indicators of the overall test are mainly the receiving gain and the dynamic range.It is indirectly calculated by measuring the IF output power value.The measured gain at 35 GHz can reach 18.25 dB,and the dynamic range is-85dBm~-15 dBm,which meets the design requirements.