Research And Design Of Transmit-receive Switches For 5G Mobile Communications

With the rapid development of the 5G mobile communication,the 5G working frequency band is divided into Sub-6GHz and millimeter wave frequency bands which is24.25-33.4GHz.When the 5G era arrives,more and more standards and frequency bands as well as non-cellular services need to be supported by the mobile communication devices at the same time.The RF switch which is the backbone of the transceiver system also ushered in its research boom in recent years.Based on 5G requirements of the two frequency bands,a single-pole four-throw(SP4T)RF transmit-receive(T/R)switch operating at 0.1-6GHz and a single-pole double-throw(SPDT)RF T/R switch operating at the millimeter wave frequency band of 24.25-33.4GHz are presented in this paper.Among them,the high power capacity SP4T switch operating at 0.1-6GHz is implemented in 0.18um SOI CMOS technology.The stacked-FETs method is adopted to improve the power processing capability,but under the traditional bias,the gate body area of the switch tube cannot achieve ideal isolation,which leads to voltage imbalanced division of the OFF-state stacked-FETs chain.Therefore,a novel bias which is better to solve this problem is proposed in this paper,which cleverly emploies the criterion of series voltage division to achieve uniform voltage division of the stacked-FETs chain,thereby improving the power processing capability of the overall circuit.In addition,as result of the reduction of signal leakage,insertion loss also been optimized accordingly.The SP4T switch chip area in view of this technology is 0.85×0.82mm~2.In each ON/OFF arm,the measurement results show that the largest insertion loss and the smallest isolation are 0.24d B/0.34d B/0.46d B/0.45d B/0.72d B,31.3d B/25.5d B/23.5d B/20d B/15.7d B respectively at 0.96/1.9/2.7/3.6/6GHz.Among 0.1-6GHz,the worst value of return loss is 14d B.0.1d B compression point(P0.1d B)is greater than 39d Bm,and when the input power is 26d Bm,the second harmonic(H2)and third harmonic(H3)are-73.5d Bm/-73d Bm/-75d Bm,-77d Bm/-73d Bm/-75d Bm respectively at 0.9/1.9/2.6GHz.Excellent RF performances are achieved by this SOI SP4T switch chip.A low insertion loss and high isolation SPDT switch operating at millimeter wave band of 24.25-33.4GHz is implemented in 0.15um GaAs pHEMT technology.At the millimeter wave band,the series-parallel classic architecture which appears a large loss and meet the requiement of isolation difficultly is no longer applicable due to the higher frequency,the more significant parasitic effect.The structure of series transmission line and multi-segment parallel transistors are adopted in this article,which optimizes the entire switch structure as a filter problem.On the one hand,a quarter-wave impedance converter is adopted to replace the series transistor structure to achieve better input matching.Thus,the insertion loss is significantly reduced;on the other hand,on the premise of ensuring that the insertion loss meets the index requirements,in order to greatly improve the isolation,a three-segment transistor parallel architecture which based on the principle of filter synthesis is designed.On the basis of the architecture,the area of the millimeter-wave GaAs pHEMT SPDT switch chip is 2.1×1.1mm~2.On-chip experimental results show that insertion loss is less than1.12d B,the isolation is greater than 33d B and the input/output return loss is better than 11d B from 24.25GHz to 33.4GHz.The expected performances are reached by the GaAs pHEMT millimeter wave switch.