Two coplanar Ka-band monolithic integrated SPST switches were designed, fabricated and characterized. The modeling of the coplanar waveguides and discontinuities as well as the comparison with the measured performance of the MMICs is described. InGaAs/InP PIN diodes are used as active switching elements in order to achieve excellent mm-wave performance. The turn-on voltage is 0.4 V and a cutoff-frequency of 5.4 THz is achieved. The MMICs demonstrate isolation values as high as 24.4 dB (24.2 dB) and low insertion losses of 0.41 dB (1.13 dB) at the design frequency.
