Design of a 24-GHz dual-polarized rectenna integrated on silicon

This paper presents the design of an integrated and differential rectenna on silicon, operating at 24 GHz. The antenna is dual-polarized and composed by four patches on a synthetized low effective permittivity dielectric. The substrate is a structure composed of three layers of high-resistivity silicon (
$\varepsilon_{\mathrm{r}}= 11.9$
) where the central layer has an air cavity equal to the dimensions of the antennas. The feeding solution is performed by planar microstrip lines with inset feeds. A shunt configuration was chosen for the rectifiers with GaAs diodes. The silicon substrate assures the complete integration for on-chip systems and despite the lossy material chosen as substrate, each patch antenna presents 83% of radiation efficiency with a maximum gain of 4.82 dBi. The overall efficiency of the rectenna is 43% at a received power level of 14 dBm.