Abstract: The design of the double-layer antenna consisting of three arms which are printed on opposite sides of anelectrically thin dielectric substrate and connected through a parallel microstrip is presented. The antenna is simulated anddesigned by the electromagnetic software Ansoft HFSS. The calculated results agree well with the experimental results. Therelative bandwidth of this antenna can reach 64% with the VSWR less than 2, which shows its good electric characteristics.