Monolithic tunable active inductor with independent Q control

A 1.1-GHz fully integrated GaAs MESFET active inductor is presented in this paper. Both the inductance and loss resistance are tunable with the induct ance independent of series loss tuning. The measured loss resistance is tun able over a -10- to +15-Omega range with a corresponding change in inductan ce of less than 10% at 100 MHz and less than 4% for frequencies above 500 M Hz, The inductance is tunable from 65 to 90 nH, Considerably larger bandwid ths can be achieved depending on the fabrication technology employed and th e intended application of the circuit.