Monolithically integrable active microwave inductor

A new approach to implementation of a GaAs monolithic microwave gyrator, or active inductor, is presented. The approach requires no resistors and only very small capacitors. The circuit is very compact, and facilitates small-area microwave inductors with values much larger than can be achieved by spiral inductors. A circuit built using this technique has an inductance of 5.8 nH over the frequency range of 45 MHz to 1 GHz. Methods to extend the operating frequency of the gyrator and improve the Q value of the active inductor are discussed.