A Microstrip Rat-Race Coupler for Narrow-Band Operation in the X-Band

Abstract

This paper proposes, designs, describes, analyses, and simulates a novel microstrip rat-race coupler for narrow-band operations in the X-band (8 GHz to 12 GHz), namely the 9.5 GHz to 10.3 GHz sub-band. This proposed four-port passive microwave device was realized utilizing microstrip technology with pure copper (lossy) being used as a metal in the conducting layers (transmission and ground plates) and Rogers TMM6 (lossy) being used in the dielectric layer. A wavelength of 3 cm (30 mm) was considered for the necessary calculations. The metal layers have a thickness of 0.3 mm with the dielectric layer having a thickness of 1.5 mm. Required simulation was achieved using CST Microwave Studio (a 3D Electromagnetic Simulation product maintained by Simulia, a subsidiary of Dassault Systèmes) for accurate results. The proposed design has shown stable and acceptablesimulated values for the required bandwidth (the 9.5 GHz to 10.3 GHz sub-band) present in the X-band (8 GHz to 12 GHz) which constitutes part of the microwave band in the electromagnetic spectrum.