Dual-band circularly polarized textile antenna with split-ring slot for off-body 4G LTE and WLAN applications

Abstract

The design of a dual-band circularly polarized wearable textile antenna is presented. The antenna consists of a slotted split-ring textile patch with a full ground plane. It features a 46 × 46 mm2 square patch over 70 × 70 mm2 ground plane using a 3-mm felt substrate. The proposed square radiator is modified using slotted split-ring to cater for dual-band resonance. The antenna is capable of providing dual-band coverage for the entire 1.8 and 2.6 GHz for the Fourth-Generation (4G) Long-Term Evolution (LTE), and for the 2.45-GHz Wireless Local Area Network (WLAN) applications. The antenna featured an impedance bandwidth of 70 MHz (1.76–1.83 GHz) in the 4G LTE (Band 3) and 400 MHz (2.36–2.76 GHz) in the Industrial, Medical and Scientific (ISM) band. The measured 3-dB axial-ratio bandwidths are 2.8% (in the lower band) and 4.2% (in the upper band) with a maximum realized gain of 3.2 dB at 2.45 GHz. Simulations and measurements indicated a good agreement with suitability to be applied in the 4G and WLAN bands.