A Dual-Band Balun Using Broadside-Coupled Coplanar Striplines

In this paper, a dual-band balun is presented. Based on the traditional Marchand balun configuration, this device utilizes a pair of lambda4 coupled-line sections and a single lambda4 open-circuit stub to achieve a dual-band balun-type function. An experimental prototype, operating at both 2.4- and 5.8-GHz bands, has been realized on a traditional printed circuit board using the broadside-coupled asymmetric coplanar stripline technique. Experimental measurements show good agreement with full-wave computer simulations, showing good potentials for dual-band/multiband RF front-end modules.