Impact of Bending on the Performance of Circularly Polarized Wearable Antenna
Rizwan, Muhammad; Sydänheimo, Lauri; Ukkonen, Leena (2015-07-06)
The Electromagnetics Academy
Julkaisun pysyvä osoite on
Wearable electronic devices are becoming a part of human clothing for applications such as sensing, navigation and health monitoring. Textile antennas are a strong candidate for transceiver node in wearable applications due to their flexibility and low cost. In wearable systems, flat surfaces are not always available so the antenna should be able to retain its performance in bent conditions. This paper analyses the effects of bending on the performance of a circularly polarized textile antenna. The antenna under test is made on Denim substrate for Industrial, Scientific and Medical (ISM) band and Wireless Body Area Network (WBAN) applications at 2.45 GHz. Copper tape is used as the conductive material for the patch and the ground plane on 1mm thick Denim substrate. Rectangular slot along diagonal axes at the center of the circular patch is used for achieving circular polarization at 2.45 GHz while bandwidth enhancement is done by using partial and slotted ground plane. The measured operating frequency range of antenna spans from 2.42 GHz to 2.58 GHz with gain of 2.25 dB at 2.45 GHz. Bending in both xz and yz plane is done by placing the antenna on cylinders with different radii (50mm and 75mm) and then analyzing the effects on return loss, bandwidth, axial ratio and radiation characteristics. Fabricated antenna shows good conformity between simulated and measured results. A set of comparative results of antenna in free space and bending conditions are compared to validate the operability of antenna with bending in different planes. In future, the performance of antenna can be analyzed on different body parts like arms and legs etc. to validate its operability for BAN applications in vicinity of human body.
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