A5-bits Digital Phase Shifter Based On MEMS Singlepole Multi Throw Switches

Microwave and millimeter-wave phase shifter is a key component of thetelecommunications and radar phased array antenna. Phase shiftersbased on MEMSswitches has the characteristics of simple structure, easy to implement, low insertionloss, high precision, which has a broad application space and great prospects fordevelopment in the future.The thesis Design a RF MEMS five bits switched-linephase shifter of8to12GHz.Firstly,established the equivalent circuit model of MEMS single-pole-multi-throwswitch, and fit its parameters.Secondly,analyzed the3D physical models and microwavecharacteristics of the gold bonding wires and extracted theparameters of its equivalentcircuit model.Finally, designeda topology of the five-bit phase shifter based onsingle-pole-multi-throw switches, precisely designedthe length and shape of the delayline and reference line, and then simulatedthe S-parameter of the phase shifter by usingthe equivalent circuit model.The simulatedinsert loss of each phase shift state of8to12GHz is better than-2dB, return loss is better than-20dB, the precision of phase shifting isless than1°. The testedinsert loss of each phase shift state of0to12GHz is betterthan-3.5dB, the tested average insert loss of8to12GHz is about-3.2dB, the testedreturn loss is better than-15dB of0to12GHz band, seriously deterioratedafter10GHz,the average Return Loss at12GHzis close to-10dB.The absolute error of the phase shiftin most of the phase shift state is less than2°, meeting the design specifications, but inthe phase shift state of303.75°,213.75°,123.75°,33.75°, the absolute error in morethan5°.At last, analyzed the reasons for the deterioration of some S-parameter,summed up the shortcomings in the entire phase shifter, and came up with someimproved method.