Millimeter-Wave SPDT Discrete Switch Design with Reconfigurable Circle Loaded Dumbbell DGS

The use of a switchable circle loaded dumbbell defective ground structure (DGS) for wideband isolation of a millimeter-wave (mm-wave) single pole double throw (SPDT) discrete radio frequency (RF) switch in a 5G application is discussed in this research. To examine the performance of the SPDT switch with switchable DGS, it was built and then simulated in CST Microwave Studio software. The performance of the switchable DGS was validated by fabricating and measuring the switchable DGS. As a result of the simulation and measurement, the switchable DGS has a wideband bandstop response with good attenuation (> 10 dB) and thus assisted the SPDT switch in producing usable wideband isolation with fractional bandwidth (FBW) of 15.49% at isolation levels greater than 30 dB for the 26 GHz band mm-wave. Furthermore, the SPDT switch's transmit mode exhibited low insertion loss (< 1 dB) and high return loss (> 10 dB), indicating a good allpass response.