A novel design of ratrace coupler using defected microstrip structure and folding technique

Abstract

This paper describes a size miniaturized rat-race coupler using defected microstrip structure called meander spurline and folding technique. By etching a meander spurline on microstrip line, slow wave effect is introduced and size reduction is achieved. The length of the quarter wave transmission line is reduced by 25.76%. The proposed rat race coupler is compact and is 60.17 % smaller than the conventional rat race coupler.