RF and microwave phase shifter using complementary bias techniques

A novel method for the design of an RF phase shifter using a standard foundry process is described. This phase shift achieves very low and near-constant insertion loss. The proposed method uses 'complementary' control techniques to keep variable parasitic resistance in a standard transistor to a minimum. Using an only single stage reflection configuration which employs N varactor diodes as a reflection terminator and M varactor diodes, a minimum insertion loss variation can be obtained. The technique is verified by measurement when N=M=1.