A Variable Negative-Inductance Integrated Circuit at UHF Frequencies

A floating variable Negative Impedance Inverter (NIl) circuit is proposed that is derived from Linvill's unbalanced negative impedance converter. A negative-inductance Integrated Circuit (IC) has been realized using the IBM 8 HP BiCMOS process with an inductance that tunes from -64 to -40 nH. The IC is short-circuit-stable (which has been verified by experiment) and is dc coupled at the terminals, making it directly applicable to susceptance cancellation for slot antennas and artificial magnetic conductors. This letter reports the circuit topology, measurement technique, and measured data.