Design of Marchand balun of spiral shape using physical transformer model on silicon integrated passive device substrate

A simple and effective technique for designing integrated Marchand balun is presented in this paper. The approach uses the physical transformer model to replace the lossy coupled transmission lines in a conventional design. As a demonstration and validation of the design approach, a spiral-shaped Marchand balun using silicon integrated passive device (IPD) technology has been carried out to provide low insertion loss and high common-mode rejection ratio (CMRR) over a remarkably wide bandwidth around an operating center frequency of 2.45 GHz. Comparison among modeled, EM simulated and measured results shows good agreement.