物联网学报 (Jun 2018)
Off-body channel modelling and diversity reception approach using wearable circularly polarized antenna
Abstract
An anti-fading diversity receiving approach to body-area communications was proposed.A pair of opposite-sense called planar endfire circularly polarized antennas (PECPA) was employed to implement the receiving approach.The wide beamwidth CP characteristic of the PECPA was used to mitigate the height-dependent fadings.Antenna designs and body-area propagation measurements were performed at 5.8 GHz-band.An off-body channel model was established,and a channel simulator was accordingly developed.All results were compared to the cases using linearly polarized (LP) antennas diversity on equal conditions.The results show that the equal-gain-combination (EGC) signal levels for CP diversity reception are 2.1 dB greater than the LP one (with polarization mismatching loss removed).The rootmean-square delay spread (RDS) and number of multi-path component (MPC) can be significantly reduced.In addition,the simulated bit error rate (BER) of the body-area communication system using CP diversity can be improved by one order of magnitude compared the LP diversity one.The correctness and effectiveness of the proposed approach has been evidently validated by the experimental and simulated results.
