A COMPACT LOW-PROFILE AND QUAD-BAND ANTENNA WITH THREE DIFFERENT SHAPED SLOTS

A compact quad-band slot antenna is presented in this paper. The proposed antenna consists of ground plane, dielectric material and top radiation patch. Firstly, symmetrical L-shaped slots are inserted in a radiation patch. Then to achieve multiband performances, symmetrical square spiral slots and a snakelike area with two symmetrical arms enclosed by a long slot in the ground plane are adopted. The process of design and parametric studies are illustrated in detail. The final quadband antenna has a small size of 0.22λg × 0.28λg = 17 × 22mm2 (where λg is the guide wavelength) and covers the frequency bands from 2.39 to 2.48 GHz for lower WLAN, 3.64–3.73 GHz for downlink and 5.98–6.30 GHz for uplink standard satellite communications, and 6.97–7.18 GHz mainly used by the Indian National Satellite System (INSAT). The measured results of the proposed quad-band antenna are in accordance with simulated analysis and show good performance of return loss characteristics, radiation patterns, bandwidths and gains. Especially, with a very small size, the proposed antenna is suitable to be integrated with a portable device for varieties of wireless communication applications.