I think you all can google and find some papers on rectennas. In principle people believe that by connecting a rectifier to an antenna, they can harvest reasonable power over a distance.
They can but the results are not reasonable.
One big problem is that so far the rectifiers are detectors for RF up to microwaves, and RF detectors are designed to rectify low RF power, up to say 0 ..+10 dBm, with and output of 3V/ mW to an open load. if loaded with ~100 Ohms to generate some DC power, the result becomes poor, as the rectifier RF/DC efficiency is < 10 per cent in the best case.
High-power efficient RF/microwave detectors need only to be discovered.
As an antenna one can use a dipole or any other type, but connecting a detector/rectifier usually causes a heavy mismatch (also RF power-dependent), so most RF power is reflected back. Rather unreasonable efficiency is thus achieved only for a narrow RF input power range, and a light load.
Rectenna is then best if an array of antennas/rectifiers covers an area unto which the RF/microwave beam is pointed, and rectified DC outputs are summed.
So far the best results at UHF and microwave bands with good rectennas are only able to load a capacitor and discharge it into a LED, one blink a minute or so. A low-power microprocessor can be used as is done in some new sensors.
So far, much ado for almost nothing. Technically not reasonable efficiency. Go and invent a better RF/microwave rectifier first!