Numerical and experimental analysis in multilayer coupling structures

A novel broadband multilayer stripline coupler consisting of two parallel striplines coupled through a small aperture is reported in this paper. Experimental and numerical results based on the Transmission Line Matrix (TLM) method show that the coupler provides ¿15 dB coupling over the entire band from 15 to 45 GHz. A hybrid technique combining the TLM numencal method with a linear simulator was used to optimize the coupling between two striplines etched on different substrates in a considerably reduced time. Also, the effect of shorting pins on the parallel plate modes of inhomogeneous stripline was considered in the analysis in order to suppress these modes and to improve the coupling.