Multi-mode resonator based asymmetric broadband 10dB directional coupler

A broadband coupler has been constructed using multi-mode resonator (MMR). The resonator primarily resonates in four distinct modes of frequencies. Out of these, three modes are responsible for broadening the operating band. Operating bandwidth may be tuned by the impedance ratio of the proposed resonator. The coupling is tunable by the gap between coupled transmission lines of the coupler. Finally, a forward-wave 10dB directional coupler ranging from 4 to 8 GHz has been designed. The design has advantages like single layer, without bond-wire and compact size.