Ridge‐shaped narrow‐wall directional coupler. Tight coupling and high‐power handling capability

Abstract A new ridge‐shaped narrow‐wall directional coupler is proposed which can realize a tight coupling and a high‐power handling capability. In the proposed coupler, the right‐angled corners of the coupling slot of the conventional ridge‐shaped directional coupler are rounded off so that a tight coupling characteristic can be obtained in a broad frequency range. The new structure preserves the features of the conventional ridge‐shaped coupler, that is: (1) flexibility of the spatial arrangement of the two coupling waveguides, and (2) the possibility as a variable power divider. The boundary element method has been used for the electromagnetic analysis. The obtained performances are such that the coupling is 1.5±0.5 dB, the return loss is more than 20 dB, and the isolation is more than 20 dB in the frequency range of 27 to 33 GHz. The measured coupling characteristics agree well with the computed results.