A Low-Profile IR-UWB Antenna With Ring Patch for WBAN Applications

A compact ultrawideband (UWB) antenna for on- body communications is proposed herein. The antenna consists of a mono- cone and a shorted ring patch. By using a ring patch with four shorting pins, the proposed antenna operates at TM41 resonance mode in the low-frequency band and achieves a compact low-profile structure with monopole-like radiation characteristics. The antenna has overall dimensions of 64 mm × 64 mm × 7 mm (0.64 λ0 × 0.64 λ0 × 0.07 λ0at 3 GHz) in the impulse radio UWB (3.1 GHz - 10.6 GHz) band and a 10-dB return loss bandwidth of 121.1% in the range from 2.8 to 11.4 GHz. The antenna performance was simulated and measured in free space and on a homogeneous human equivalent phantom to account for the human body effect. The results show that the antenna characteristics are relatively stable regardless of the existence of a human phantom.