Dual-band circularly polarized textile antenna with split-ring slot for off-body 4G LTE and WLAN applications
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 x 46 mm2square patch over 70 x 70 mm2ground 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.