Wideband log‐periodic phase shifters

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 main‐line models with different characteristics. The design process follows a log‐periodic phase shifter theoretical analysis and optimization algorithm of the desired designing platform for circuit tuning. Three proposed main‐line log‐periodic 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. S11 and S21 are better than −10 and − 1.45 dB in considered 141% fractional bandwidth (1.40‐8.11 GHz) for a 130° continuous phase gradient, respectively.