Dual-Functional Ultrawideband Antenna With High Fidelity Factor for Body Area Networks and Microwave Imaging Systems
Zahra Lasemiimeni, Zahra Atlasbaf, Nima Karbaschi
Abstract
Microwave Imaging (MI) and Body Area Networks (BANs) technologies are widely used in healthcare systems. A dual-functional compact ultrawideband (UWB) antenna with a high on-body and off-body fidelity factor is presented in this paper. The antenna’s design approach is based on analyzing the return loss, the antenna’s gain, the phase of S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> , and the group delay over the UWB frequency band, in each designing step, to achieve the highest level of fidelity factor in both E- and H-plane. The final design (Ant. 3) consists of a circular ring with six intersecting rings in the radiating element and an elliptic ground plane with an overall size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$16\times 20\,\,mm^{2}$ </tex-math></inline-formula> . Simulated and experimental evaluations both in free space and on-body prove the excellent operation of Ant. 3 within the FCC UWB bandwidth of 3.1 to 10.6 GHz in terms of return loss and fidelity factor (greater than 0.9 at all angles). For body area communication, the final design presents the fidelity factor greater than 0.93 near the human arm. Also, for breast cancer detection applicability, a 12-element array of Ant. 3 is located around a conical breast model. The results show the antenna’s promising performance in detecting 6-mm average diameter malignant tumor and 3-mm average diameter benign tumor.