A Research And Design Of Microwave Switches Based On SISL

The microwave switches are widely used to control the radio frequency(RF)signal switching or select the RF signal path,which are important components of most wireless communication systems,such as phased array radars,mobile phones,satellite communication systems and unmanned aerial vehicles.Microwaves transimmision lines used in microwave switches include microstrip lines,coplanar waveguides and fin lines,etc.and the control devices include PIN diodes or FET transistors.The traditional microwave transmission lines commonly used in microwave switch design are flat transmission lines and non-planar transmission lines.Due to the conductor loss,radiation loss and dielectric loss of the planar transmission line,it is not suitable for the microwave circuit in millimeter-wave band and it can't constitute the components with high Q value.Non-planar transmission line loss is low,Q value is high,but as a three-dimensional structure,non-planar transmission line is difficult to be compatible with the plane transmission line or discrete devices,and it is huge and bulky.The substrated integrated suspended line(SISL)mentioned in this thesis,with low loss,low dispersion,high Q value and other features,overcomes those shortcomings of traditional microwave transmission lines,but also it is very compatible with the flat transmission line and discrete devices.A single-pole-four-throw microwave switch based on SISL is designed.The insertion loss is less than 0.5 d B in the frequency range of 4-6 GHz,and the isolation between each port is more than 40 d B.Besides,both a low loss single-pole-double-throw(SPDT)filtering switch and a high isolation SPDT filtering switch are designed based on SISL.The insertion loss of SISL low loss filtering switch is 0.9 dB,the passband isolation is 20 dB,the center frequency is 0.98 GHz,the 3-dB bandwidth is about 56%,the circuit size with self packaging is 0.24 × 0.16 ?g2.The isolation of SISL high isolation filtering switch is up to 40 d B in the passband,insertion loss is 1.8 dB,the center frequency is 1 GHz,the 3-dB bandwidth is about 60%,size of the circuit with self packaging is only 0.13 × 0.11 ?g2.Comparing to the traditional filtering switch designed on microstrip line,the size of SISL SPDT filtering switch based on SISL is 50% smaller.At the same time,the loss is relatively smaller.In last chapter of this thesis,a WiFi band SPDT microwave switch based on a 0.15 ?m GaAs process is introduced.Two metal layers transmission line with lower loss and two metal layers inductor,which is used to form high Q matching network,are applied to minimize the insertion loss and extend the bandwidth of the proposed SPDT microwave switch,.The measurement results shown that,in frequency range of 2-3 GHz,0.6 dB insertion loss and 28 dB isolation are achieved.Besides,in the simulation results,it shown that both high power handling ability and good linearity are obtained by the proposed SPDT switch.The chip size is 1.3×0.9 mm2.