Comparison Between a Multiband PIFA and a Ultrawideband Archimedean Spiral Antenna for Energy Harvesting in Microwave Bands

This paper shows a comparison between a linearlypolarized multiband PIFA (Planar Inverted F-Antenna) and a circularly-polarized ultrawideband Archimedean spiral antenna, both designed to be low-cost RF harvesters and to capture the spectrum energy in the bands of interest (FM, DTT, LTE, GSM, WiFi and WiMAX). It is commented and demonstrated how the Archimedean spiral, which works between 0.4 GHz and 18 GHz, presents a better behavior in most of its radiation characteristics: efficiency, matching, depolarization losses, etc.; and it is more tolerant to slight variations in some of its parameters, as Monte Carlo simulations show. It also solves the interoperability problem of the antenna between different countries, where frequency assignment plans can vary.