Recent article on rectifying antenna
https://www.stripes.com/news/us/air-force-lab-working-on-process-to-beam-solar-power-from-space-to-earth-1.640722Old tech, new use
The “spider” project – Space Solar Power Incremental Demonstrations and Research, or SSPIDR – is actually building on technology created decades ago. Photovoltaic beaming, or wireless power transfer, was demonstrated in the 1970s, said SSPIDR project manager James Winter. It’s based on gathering solar energy with photovoltaic cells and then converting it to radio frequency for beaming from antennas to receivers.
That process is used for satellite TV, whereby solar energy is used to propagate radio frequency that’s then sent to the ground for communications. In the case of wireless power transfer, the radio frequency is received by a “rectifying antenna” that converts the frequency back to electricity, Winter said.
“The concept has been around a while,” Winter said. “With normal solar systems, you collect solar energy and convert it to direct current to charge up batteries on a satellite. … With a solar-to-radio-frequency module, there is no storage – you convert the solar energy to direct current and then to radio frequency with integrated circuits for transfer to a rectifying antenna that converts it back to direct current.”