Research And Design Of Multi-beam Phased Array Receiver Components In EHF Frequency Band

Phased array antenna technology is an important part of radar technology and modern communication technology.Increasing military and civilian needs strongly promoted the rapid development of phased array antenna technology.Broadband and multi-beam are two important aspects for the development of phased array antennas in the near future.The multi-beam receiver is an important part of the phased array antenna.Microwave multilayer board technology and microwave multi-chip module technology(MMCM,Microwave Multi-Chip Module),combined with microwave monolithic integrated circuit(MMIC,Microwave Monolithic Integrated Circuit),We realized complicated interconnection of micro-wave circuits,and completed the subject "EHF-band Multi-beam Phased Array Receiving Module".First of all,this paper investigated and analyzed the current research status of multi-beam receivers,and focused on the key technologies involved in the design: microwave multi-layer circuit topology technology and multi-beam receiver integration technology.According to the requirements of the subject specfications,the overall scheme design was completed,including receiver implementation,single-channel link calculation,and system-level simulations.Key technical specfications were evaluated and budgeted.Secondly,in order to solve the prominent problem of high-density transmission lines in the multi-beam combination network,inter-layer interconnection is used,and four types of vias and coupled vertical transition structures are mainly studied.Based on the calculation and analysis of the four-port directional coupler theory and the absorption cavity theory,a wideband vertical coupling transition structure based on back-cavity and coplanar waveguide to a coplanar stripline is designed,to achieve a wide frequency band and low insertion loss of different interlayer signals.According to the messured results,a single cavity-coupled transition structure resulted a return loss of less than-10 d B and a typical insertion loss of 1d B in the 42-48 GHz range.At the same time,through simulation and test of two types of classic via-type vertical transition structure,the back cavity-coupled transition structure shows a wider bandwidth under the condition of equivalent insertion loss of the via-type.In addition,the via-type transition structure requires high machining accuracy.In large-area circuits,the via shift phenomenon is more serious.In contrast,the coupling form has better tolerance performance and is easy to realize.Due to the limitation of the horizontal size of the components,combined with the analysis results of the mentioned transition structure before,In the design of the multi-beam combination network,We used the form of via-cavity coupling cascade to ensure the broadband characteristics and to improve the integration of the network.The three-dimensional structure of the total circit is too complex,so we used unit circuit modeling and simulation to improve the simulation efficiency.Finally,the entire eight-beam and eight-channel combination network is simulated.In the frequency range of 42-48 GHz,the port return loss is less than-20 d B and the insertion loss is less than 0.2d B,isolation is greater than 35 d B.Finally,the RF circuit,control circuit and three-dimensional structure of the eight-beam receiver module are designed in detail.The module size is 132 mm × 75 mm × 13.5mm.After machining and test,in the frequency range of 44.5 ± 1.5GHz,the gain of the receiver is greater than 45 d B,the channel flatness is less than 3d B,the noise figure is less than 3.5d B,the phase shift accuracy is less than 5 °(RMS),and the attenuation accuracy is less than0.4d B(RMS).The design of this receiver provided a better solution to the problems of complicated multi-layer transmission line and signal crossover in the multi-beam combination network,and provided an effective solution for the integration design of multi-beam component.