A wideband quadrature generator IC using a varactor-compensated feedback network

In this paper a novel quadrature generator is presented that exhibits a 110% operating frequency bandwidth. Existing circuits are unable to provide a quadrature signal over such a large fractional bandwidth. They are also highly susceptible to component tolerances that can often shift the center operating frequency rendering the circuit unusable. In this work, this issue is mitigated with the use of a negative feedback network that is able to actively compensate the circuit using varactors to match the operating frequency. In this manner, the bandwidth of the quadrature generator can be significantly increased. Simulation results show an operating frequency span from 1 to 6 GHz while maintaining a phase error below 5° and ±2 dB in amplitude error. The circuit, without bonding pads, uses an area of only 0.17 mm².