Wideband log‐periodic phase shifters

Abstract

This paper presents concept of wideband log-periodic phase shifter (LPPS) and also three novel microstrip phase shifters using a log-periodic structure for the first time. The process of achieving the goal of wideband releases three mainline models with different characteristics. The design process follows a logperiodic phase shifter theoretical analysis and optimization algorithm of the desired designing platform for circuit tuning. Three proposed main-line logperiodic phase shifters are short-circuited stub LPPS (SS-LPPS), double-sided LPPS (DS-LPPS), and Multilayer coupling LPPS (MC-LPPS). Compact size, planar, ease of fabrication, and wideband are the critical characteristics of the proposed structures. The broadband characteristic of the MC-LPPS is due to top and bottom Log-Periodic microstrip patches broadside coupling of 2 dB through an elliptical slot placed in a ground plane as a middle layer of a structure. Even-odd model analysis of design verification method employed. The optimized overall dimension of the final wideband proposed structure on the low-cost Rogers RO4003C substrate is 35 mm  20 mm, Fabricated and tested. Experimental and simulation results have good agreement. S 11 and S 21 are better than À10 and À 1.45 dB in considered 141% fractional bandwidth (1.40-8.11 GHz) for a 130 continuous phase gradient, respectively.