Design of monopoles antenna for on-body communication links at 2.45 GHz

Abstract

Numerous researches have been devoted to the development of the wearable antenna for its functionalities in on-body communications. The printed monopole antenna fulfils the requirements as well as having wideband matching characteristics, omnidirectional radiation patterns and compact size. Transforming wearable antennas into a compact antenna for wireless on-body communication which operates at 2.45 GHz and to investigate their performances on the body are the objectives of the research. In this research, three types of printed monopole antennas with different configurations are proposed. A microstrip patch antenna is selected as the basic design and modifications on the radiating patch for these three antennas were tested on movements of normal activities of a human in an office environment using Computer System Technology (CST). To verify the performance of the proposed antenna, return loss was simulated using CST and measured with network analyser. Path loss measurement for five on-body channels which are belt-to-chest, belt-to-wrist, belt-to-head, belt-to-back and belt-to-ankle was measured with vector network analyser. For the antenna performance on the body, the belt-to-head body channels gave the best result for the path loss measurement with highest path loss mean values about -30 dB. It was also found that the developed antennas can perform well at 2.45 GHz with good return loss below than -10 dB, and both simulated and measured results were in agreement. These proposed antennas worked well with wide operating bandwidth about 17~32%. However, each of these antennas has its own superior feature based on the configuration that could enhance the compactness of the antenna.