Using a VIA-Less CRLH Transmission Line to Design Compact Wilkinson Power Dividers and Rat-Race Couplers

A method for design and implementation of a compact via-less Composite Right/Left-Handed Transmission Line (CRLH TL) is presented. By introducing a new circuit model, the CRLH transmission line behavior is studied versus the parameters variations to achieve the desired characteristic impedance and electrical length. Then a compact quarter wavelength CRLH transmission line with 70 Ω characteristic impedance is designed as an example. Finally a very compact four way Wilkinson power divider and a rat-race coupler are designed and fabricated by using this type of CRLH TL which exhibit about 75% and 80% compactness, respectively.