Geometrically progressive stub loading scheme for miniaturization of transmission line-based components

Abstract

This paper presents a novel slow wave structure (SWS) using geometrically progressive loaded shunt stubs for miniaturization of microstrip lines. It is observed that, compared to the conventional periodically stub loaded SWS, the proposed technique renders further miniaturization of around 20%, theoretically. Apart from that, this technique also helps in suppression of higher pass bands inherently present in SWSs. A detailed analysis of this technique has been carried out with corresponding design scheme. For proof of concept, this miniaturization scheme is applied to a rat-race coupler designed at 2 GHz, where 75% reduction in overall footprint is observed. The simulated and measured results are found to be in good agreement with the proposed theory. © 2020 Wiley Periodicals, Inc.