Flexible milimeter-wave microstrip patch antenna array for wearable RF energy harvesting applications

In this paper, a series-fed milimeter-wave microstrip patch antenna array operating at 28 GHz is presented for wearable radio-frequency (RF) energy harvesting applications. The made of 4×4 rectangular elements on polyethylene terephthalate (PET) substrate to provide conformability when directly attached human body parts. A 4-way Wilkinson power divider connected the RF combining. overall size 47×28×0.25 mm. half-power beamwidth (HPBW) can be increased up 151.9⁰ via structural deformation making it suitable performance investigated in terms impedance matching, gain and radiation pattern. average simulated specific absorption rate (SAR) 0.52 W/kg which well below safety limit 1.6 averaged over 1 g tissue 100 mW input power.