Study on Extremely Compact Triple Band-Rejected Antenna in Indoor Propagation Channel for IR UWB and Biomedical Applications

This paper investigates the frequency- and time-domain features of an extremely compact super-wideband slot antenna designed for impulse radio (IR) ultra-wideband (UWB) and biomedical applications. The antenna employs a circular radiation patch and a rectangular slot in the ground plane, with optimized dimensions to achieve super-wide bandwidth. To address interference issues with co-existing narrowband systems, two inverse L-shaped stubs are connected to the ground plane, effectively rejecting the WiMAX spectrum. Additionally, two circle-like ring slots are embedded into the radiation patch to create band-rejected features for WLAN and X-band downlink frequencies, respectively. Despite its compact size of 14×14 mm² (0.13λ
_g
×0.13λ
_g
), the antenna offers a bandwidth extending from 2.8 GHz to over 20 GHz, making it suitable for UWB (3.1-10.6 GHz) and Ku band (12-18 GHz) applications. The paper also explores the antenna’s impact on transmitting and receiving ultra-narrow pulses for IR biomedical applications, assessed using the system fidelity factor (SFF). A noteworthy contribution of this work is the investigation of the time-domain properties of the proposed antenna in a typical indoor propagation channel. Simulated and measured results demonstrate the antenna’s favorable characteristics in both the frequency and time domains.