Key Technology Research On 8mm Band Fin Line Downconverter And Lens Antenna

Based on the project named Short-range Radar Ranging,this paper focuses on studying the key technology of the 8mm-band lens antenna and the down converter.In the design of the down converter,a finline mixer is designed.In the design of antenna,in order to reduce the weight of the lens antenna,the zoned lens is designed.The main contents of this paper are as follows:The first part of the paper is about studying the 8mm-band down converter.The single-balanced mixer structure is adopted and the finline-suspended microstrip hybrid configuration is selected to design the mixer.In the RF port,a number of grooves are used in the finline transition section for circuits matching.Then all the single-chip circuits are simulated respectively.After the mixer has been fabricated and tested,when LO is 35 GHz,the conversion loss is less than lOdB with the RF's frequency range from 32.5 GHz to 37 GHz.The isolation between LO and RF is more than 30dB and the P1dB of the RF port is more than 5dBm.The second part of the paper is about studying the key technology of 8mm-band lens antenna.The basic principle of the lens antenna and the design of feed horn is introduced.In order to reduce the weight of the lens antenna,the theory of the zoned lens is introduced.According to the characteristics of the zoned lens,the antennas are modeled and simulated respectively before and after the lens's being zoned.And compared with their simulation results,it shows that the lens is sensitive to frequency,and the feasibility of the zoned lens in reducing the weight of the lens antenna is proved.After fabricating and testing the zoned lens antenna,the results are almost coincided with the theoretical simulation.In addition,the PIN switch and the limiter are also studied.Finline circuit and shunt PIN diodes are adopted to design the PIN switch and the limiter.Then PIN switch and the limiter are simulated with simulation software.After fabricated,the tested results are given out.Then,the PIN switch or the limiter and the mixer are cascaded to test.After tested,the results almost meet the design requirements.Finally,the design of the down converter and the lens antenna and test results are summarized,deficiencies in the design are analyzed and improvements are proposed.