Broadband Branch Line Balun using Meander line on Silicon Substrate

Abstract

This article presents the design of L-band branch line balun using microstrip configuration on high resistive silicon substrate (ρ>8KΩ-cm). In comparison to earlier designs better performance is achieved by meandering all the four branches and appending a quarter wavelength short circuited stub at the upper right corner of the structure. The circuit is designed using circuit simulator of Agilent's advanced design system (ADS) and further verified using Ansoft's FEM and ADS's MoM based electromagnetic solvers. Comparative study is carried out among various simulation techniques and analyzed. Fabrication methodology along with design steps are detailed in this article. Proposed design saves around 60% print area as compared to conventional topology. Further comparison with other reported topologies have also been discussed. Keywords - Branch line balun, high resistive silicon, microstrip line, short circuited stub, via hole.