Compact and ultra-wideband CPW-fed square slot antenna for wearable applications

This paper is devoted to a compact and ultra-wideband (UWB) CPW (Co-Planar Waveguide)-fed square slot Antenna for wearable applications. In our design, the antenna fabricated on the cotton layer with dielectric constant of 1.65 with compact size of 0.76λ × 0.72λ in which the antenna has a silver based fabric radiating element. The UWB operation of this compact antenna varies from 3.2 GHz to 16.3 GHz considering the fractional band width (FWB) to be 135. To clarify for wearable applications, this compact antenna were compared with different dielectric constant such as non-woven (er = 1.15, thickness (h) = 5 mm) and FR4 (er = 4.4, h = 1.6 mm). This antenna, then, were examined both in air, and on a suit shirt situations. The Antenna which is located on body compared to antenna in air has a lower efficiency. Furthermore; it decreases the radiation toward body approximately 10 dB. It also causes frequency shifts and reduces the bandwidth. In both cases, the examinations indicated the compact antenna in the UWB is very desirable.