Voltage controlled phase shifters on CMOS technology

Implementation of voltage controlled active inductors on standard CMOS technology for 2 GHz is described. The circuit is based on a gyrator implemented with a 5 MOSFETs feedback circuit, including the DC bias. Theoretical expressions were derived with a simple but enough accurate MOSFET model. The inductor value is controlled by an auxiliary bias voltage V_tune. An MMIC with a CMOS standard technology was designed, fabricated and tested. At 2 GHz, an L=35 nH inductor with a Qap 7 and a series resonant frequency of 2.6GHz was measured. For DeltaV_tune=1.2 V, the inductor value changes from 23 nH up to 70 nH. A phase shifter application was studied: 45deg of phase shift per second order section was achieved.