Detuning effects of wearable patch antennas

The variations in the resonance frequency of a wearable 5.3 GHz textile patch antenna due to bending, human body proximity and moisture absorption are investigated. Noteworthy are the effects of proximity to human body tissue and moisture uptake, which are shown to cause variations up to 5% in the resonance frequency. Importantly, it is observed that the resonance frequency can shift both upwards or downwards depending on the loading affecting the antenna. These variations illustrate a general guideline for the maximum tuning range needed for wearable frequency-reconfigurable patch antennas.