Patent ID: 8446200
Filing Date: 2013-05-21
Classification: H03F,H03H

Abstract:
1. A system, comprising: a phase shifting network comprising at least an inductor, a first varactor, and a second varactor configured according to a pi-network, the first and second varactors having a respective first and second variable capacitance that is controlled by a control voltage, wherein the phase shifting network operates to receive an input signal and generate an output signal, the output signal including a phase shift provided by the phase shifting network; and a compensation circuit in communication with the phase shifting network, wherein the compensation circuit is configured in parallel with the first varactor and the second varactor and is responsive at least in part to the control voltage to adjust a transconductance of the compensation circuit, wherein the compensation circuit delivers a negative resistance to the phase shifting network to reduce insertion loss associated with operation of the phase shifting network, the negative resistance based upon the transconductance that is adjusted responsive to the control voltage.