UWB Gilbert downconverter utilising a wideband LR-CR quadrature generator

Abstract

An ultra-wideband (UWB) I/Q downconverter with an LR-CR quadrature generator is demonstrated using 0.35 mu m SiGe HBT technology. The I/Q outputs of this generator are always in quadrature phase at any frequency while the BJT-type active mixer inherently tolerates much LO power difference for a. at gain response. Consequently, the amplitude imbalance and phase error of the I/Q outputs are less than 1 dB and 2 degrees in the RF frequency range 3-11 GHz.