Design of K/Ka-band passive HEMT SPDT switches with high isolation

In this paper, high isolation K/Ka band monolithic microwave integrated circuit (MMIC) single pole double throw (SPDT) switches with different topologies are proposed and discussed. By using a 0.07 μm GaAs high electron mobility transistor (HEMT) process, the shunt type and series-shunt type of passive HEMT SPDT switches are designed and compared. In 24~27GHz, both switches demonstrate an isolation better than 39dB. The shunt type of switch demonstrates an insertion loss less than 1.5dB and the series-shunt type of switch less than 2dB. With a compact chip size smaller than 1.5*2 mm
²
, the designed switches can be used to form the MMIC T/R systems in the future.