Design and Realization of Spiral Marchand Balun Using CPW Multilayer GaAs Technology

Abstract

Newly developed spiral Marchand baluns using the great flexibility of three-dimensional multilayer technology have been designed, optimized, fabricated, and measured. This paper demonstrates a monolithic microwave integrated circuits (MMIC) coplanar waveguide (CPW) spiral Marchand balun with good balance performance in a wide frequency range and compact size. Even/odd mode characteristic impedance analysis was applied to optimize the balun's performance. A 2.5D simulator ADS Momentum and a true 3D simulator Ansoft HFSS were used for EM simulations providing useful insight of the components design and optimizations as compared with the measured data. On-wafer RF measurements were carried out from 45MHz to 40GHz. The measured results shows small insertion loss, good amplitude and phase balance in a wide operating frequency band. A very compact size of 0.26 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> is achieved