Research On Millimeter Wave Active Mixing Receiving Technology

The main function of mixer is to complete the frequency conversion,which is the most important circuit in the receiving system.Nowadays,with the development of millimeter wave solid-state three port devices,active mixing technology has become an important direction of mixer research.In addition,active mixing technology has been widely used in monolithic microwave integrated circuit(MMIC).In this paper,the fundamental and harmonic active mixers are studied based on a commercial K band FET.Firstly,a K band fundamental active mixer is studied,which has good performance and frequency conversion gain in a certain bandwidth.Then the K band FET is applied in higher frequency band.The U Band second harmonic active mixer and V band third harmonic active mixer are studied respectively,and the limit frequency of the FET is explored.Finally,the K band fundamental active mixing four channel receiving circuit and the Ka band harmonic active mixing four channel receiving circuit are developed.The performance of the two multi-channel receiving circuits is good,and the applicable frequency range of the FET is obtained.In addition,the joint test of the Ka band receiving circuit and the transmitting circuit developed by others shows that the transmit-receive circuit can be used for short-range sensing detection.In the research process of mixer,the field circuit co-simulation method is mainly used for nonlinear analysis.In order to facilitate the integration of the system,the transition structure of waveguide microstrip probe is studied and the experimental test is carried out.In order to realize the miniaturization of multichannel receiving circuit,the vertical interconnection structure between layers is studied to reduce the volume of the receiving circuit.In order to study the highest application frequency of FET,the core packaging of FET is studied.Through modeling and simulating the core packaging,and further experimental analysis and verification,it is concluded that the highest application frequency of the FET is 42 GHz.The test results show that the K band fundamental active mixer has conversion gain in the bandwidth of 23.1-24.1GHz,up to 5dB,which is in good agreement with the simulation results.The frequency conversion gain bandwidth of K band four channel receiving circuit is about 1.5GHz,the maximum gain in the bandwidth is 5dB,dynamic range up to 90 dB,isolation between RF ports is more than 45 dB,isolation between IF ports are more than 35 dB.The frequency conversion loss less than 10 dB bandwidth of Ka band four channel receiving circuit is about 1.5GHz,the minimum loss in the bandwidth is 5dB,dynamic range up to 80 dB,isolation between RF ports is more than45 dB,isolation between IF ports are more than 40 dB.The performance of U Band second harmonic active mixer and V band third harmonic active mixer is poor because the frequency band is beyond the highest application frequency of the FET.After testing,the maximum operating distance of the Ka band transceiver link is calculated to be 178 m.