Miniaturized Dual-Band Omnidirectional Antenna for Body Area Network Basestations

Challenges arising from body effect in design of implant and on-body antennas has dominated body area network (BAN) basestation antenna design research. However, design of an efficient basestation antenna in a compact size is also a challenge. This letter presents a miniaturized omnidirectional antenna in two bands of 403.5 MHz for medical implant communication services (MICS) and 2.45 GHz for industrial, scientific, and medical (ISM) applications. The antenna consists of two stacked center-fed circular patch over a circular ground plane. The upper and lower patches resonate in MICS and ISM bands, respectively. Each patch is loaded with two vias for miniaturization. The achieved miniaturization factors are 6.3 and 5.1 for MICS and ISM bands, respectively. Since the ${\rm TM}_{010}$ -mode is excited, the pattern is omnidirectional with a null in broadside. The measurement results show a good agreement with the simulation in terms of reflection coefficient and radiation pattern.