Masthead combiner employing asynchronously coupled resonant junctions

This paper proposes the use of asynchronously coupled resonator junctions in the design of a masthead combiner (MHC). By employing the resonator junctions, a miniaturised circuit is achieved without using any transmission-line based impedance matching circuits. The main challenge in the design is the control and implementation of the external couplings at the common ports of this all-resonator-based MHC. A four-port microstrip MHC operating at the two channels of 1.8 and 2.1 GHz has been demonstrated with a bandwidth of 1.764 GHz to 1.836 GHz and 2.058 GHz to 2.142 GHz, respectively. Good agreements have been achieved between the measurements of the prototype devices and the simulations.