Investigation on FET switch integration techniques for a tunable microwave periodic structure

A recently proposed tunable microwave periodic structure requires many switches to dynamically change its microwave propagation and radiation characteristics. The performance of a discrete Field Effect Transistor (FET) switch package, suitable for the structure, is investigated in two potential configurations. In one configuration, the switch is co-planar with the ground plane and in the other it is on a different surface. Measurements made on two test boards confirm that when the switches are turned “on” the switch insertion losses are not significantly different between the two configurations. However when the switches are turned “off”, locating the switches on the ground plane provide better isolation between RF ports.