GaN HEMT Monolithic Single-pole Double-throw Switch For 5G Millimeter-wave Applications

Radio frequency(RF)front-end transceiver components based on monolithic microwave integrated circuit(MMIC)technology are widely used in wireless communication,radar and other systems.The transmit/receive switch plays an important role of the RF front-end,its performance will directly affect the reception and transmission of signals,thereby affecting the overall performance of the front-end system.The third-generation wide band gap semiconductor material,gallium nitride(GaN),can be applied to high-power,high-performance millimeter-wave front-end circuits due to its high breakdown electric field and high thermal conductivity.This thesis utilizes a 100nm silicon-based GaN HEMT process to design single-pole double-throw(SPDT)switch MMICs for 5G millimeter-wave applications.Firstly,this paper introduces the fundamentals for switch design,and analyzes the structure of high electron mobility transistor(HEMT)devices and passive devices of D01GH GaN process.Then,a 24-30GHz symmetric SPDT switch that with the D01GH process power HEMT as a switching device is designed.The mearsured results show that the insertion loss is1.2-1.5d B,the isolation is 28-30d B,the input power 1d B compression point is greater than27d Bm,and the chip area is only 1.08mm~2.Secondly,with different performance demands of the millimeter-wave front-end transceiver branch,two asymmetric SPDT switches are designed.The bandwidth of the transmitting branch is improved by using the load effect of the disconnected branch and the short stub compensation technique.Under the condition that the insertion loss performance of the receiving branch(RX)is guaranteed to be acceptable,the insertion loss of the transmitting branch(TX)is optimized,and the insertion loss,isolation and power-handling are traded off,simulation results after layout demonstrate:1)The designed asymmetric shunt SPDT switch,operates in the frequency range of24-30GHz,features less than 0.7d B insertion loss for the TX branch,the TX-RX isolation is greater than 32d B,and the input power 0.1d B compression point is higher than 34d Bm;The insertion loss of RX branch is less than 1.8d B,the RX-TX isolation is greater than 14d B,and the input power 0.1d B compression point is higher than 30d Bm.The layout area is 1.35mm~2.2)The designed asymmetric series/shunt SPDT switch,operates in the frequency range of 24-30GHz,features less than 0.9d B insertion loss for the TX branch,the TX-RX isolation is greater than 35d B,and the input power 0.1d B compression point is higher than 33.5d Bm;The insertion loss of RX branch is less than 1.8d B,the RX-TX isolation is greater than 11d B,and the input power 0.1d B compression point is higher than 36d Bm,with 1.35mm~2 layout area.Finally,the application of GaN symmetric and asymmetric SPDT switches in the millimeter-wave front-end are studied,and the switch design in the GaN millimeter-wave integrated front-end is accomplished.