Simple-Design and Compact MIM CRLH Microstrip 3-dB Coupled-Line Coupler

A metal-insulator-metal (MIM) composite right/left-handed (CRLH) microstrip 3-dB coupled-line (CL) coupler exhibiting simple design characteristics, high compactness and immunity to spurious resonances is presented along with a rigorous design procedure. This CL coupler can be easily designed to achieve any arbitrary level of coupling. In comparison with its interdigital counterpart, this coupler is twice smaller and exhibits much higher design simplicity