This article presents a dual-band and wide-band branchline coupler with a large frequency ratio. By combining the cascade technique with cross coupled branch lines, the proposed coupler can acquire the function of wideband and dual-band. Furthermore, the proposed coupler can realize a large frequency ratio of 2.6 due to the new structure. For experimental verification, both the simulation and measurement results of the proposed coupler designed to operate at 1 and 2.6 GHz are presented. The measured results validate good dual-band performance with enhanced bandwidths (1 dB imbalance) up to 34.7% and 14.9%, respectively.

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