An Octave Bandwidth RF Harvesting Tee-Shirt

This paper presents 16 and 81-element broadband rectenna arrays screen printed on a cotton tee-shirt for harvesting 4-130 μW/cm
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power densities between 2-4 GHz. The antenna is a self-complementary tightly-coupled bow-tie array with a period of about λO/6 at the highest frequency. Each array element feed is connected to a packaged Schottky diode using silver paint. Full-wave antenna simulations are performed with specific tissue electrical parameters for the torso, as well as for a body phantom. The diodes impedance as a function of dc load and input power density is analyzed using source-pull harmonic-balance simulations. Measurements using a water-filled phantom show up to PDC=10 μW for incident power densities of 4 μW/cm
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at the center of the band, with a DC load of RDC=2kΩ.