3D-BCB Based Branchline Coupler for K-band Integrated Microsystem

This paper presents the design of a high performance and compactness coupler integrated with a 3D technology using BCB (benzo-cyclo-butene) polymer. The main interests of the proposed technology are first the possibility to design multilayer passive devices to achieve high compactness and secondly to be able to monolithically integrate both passive and active circuits as the technological process is fully compatible with ICs. This technology was used to design coupler for which high compactness is reached by applying size reduction to the transmission lines. Electromagnetic simulations have been performed and show excellent performances in terms of amplitude and phase imbalance, isolation and return loss. Several versions of the coupler have been compared to emphasis such performances versus the reduction factor