Varactor Topologies for RF Adaptivity with Improved Power Handling and Linearity

Abstract

Ultra linear silicon-on-glass varactor topologies with improved power handling and linearity have been realized. The resulting components include integrated bias networks and provide excellent low-loss performance for large capacitances (e.g. C=20pF Q>100 at 2 GHz with V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cont</sub> =2 V). Using a novel center tap circuit the linearity has been improved for narrowband two-tone signals yielding measured IIP3V values above 75 V for tone spacings >10 kHz. By implementing two varactor stacks in series with integrated bias networks the power handing improves 4x, while the IIP3V doubles. The resulting devices can be used as flip-chip components enabling linear adaptive wireless applications.