Design of a complex ratio measuring unit using enhanced branch-line coupler for wireless communication applications

This article presents the complex ratio measurement unit (crmu) design formed by enhanced 3-db branch-line couplers (blcs),which are placed symmetrically. the first crmu is formed by four wideband 3-db blcs implementing defect ground structure (dgs) and stub impedance techniques that operate over the frequency of 2.5 to 4 ghz. meanwhile,the other crmu is formed by four reduced size of enhanced two-section microstrip-slot blcs with tight coupling of 3-db over frequency of 2 to 5 ghz. the performances of the crmu designs are observed and analyzed. the blcs and crmus are designed using cst microwave studio. while,the s-parameter performances of the crmus are analyzed using keysight’s advanced system (ads) software. © 2015,penerbit utm press. all rights reserved.