A Multi-Band Asymmetric Stepped-Slot Antenna for DCS, PCS, WiMAX, 4G, and WLAN Applications

A multi-band stepped-slot antenna, fed by modified 50 Ω coplanar waveguide (CPW) transmission line is described and implemented. The designed antenna effectively supports digital communication systems (DCS 1.71–1.88GHz), personal communication systems (PCS 1.85–1.99 GHz), worldwide interoperability for microwave access (WiMAX 3.30–3.80GHz), forth generation (4G 3.40–4.2 GHz) mobile communication system, and wireless local area network (WLAN 5.15– 5.35 GHz). In order to cover the aforementioned valuable bands, in the first step rectangular slots are subtracted symmetrically from the radiating patch. Besides, stair-shaped rectangular slots are etched at the radiator edges. Also, to operate at DCS and PCS systems, dual-section CPW feed line with different widths is designed. Actually antenna is designed by using quasi-fractal methods, to cover frequency ranges of 1.64– 1.99 GHz, 3.35–4.3 GHz and 4.8–5.4 GHz (for |S11|< −10 dB). The antenna size is 75.2 × 38.54 × 1.6 mm3 and it is etched on FR4 substrate. The antenna development steps are presented and discussed in detail. Moreover investigation of important design parameters is performed. The designed multi-band antenna has respectable results such high gain in center of each operating band and considerable efficiency of 90 %, 85% and 86% in 1.85, 4 and 5GHz respectively. Also omni-directional patterns and acceptable group delay are obtained. Measurement data are presented to validate the numerical outcomes. All of these prominent features make this antenna, worthwhile for multi-band applications.