Very cool! Six years ago I worked on a mmWave (76-81GHz) imaging radar with a Rotman lens Tx and Rx. Designed as a LiDAR replacement, but we could see pipes in walls, or detect concealed weapons at ~1km.
Super cool. Didn't even know mmWave was used for radar and imaging techniques!
Isnt mmWave pretty similar (in theory) to short-ish range wireless directional antennas? What people used to call point to point "microwave" transmission?
Crazy idea but could your mmWave radar hardware also be (not simultanouslyl) used to transmit data? No idea what a Rotman Lens is but I would imagine that maybe it could be useful for transmission as well.
I've been down the mmWave rabbit hole for the last 6 months, making sensors to put around the house to control automations for lights and so forth. They're pretty great.
For my use case the advantage over PIR is they do presence detection, so no more lights shutting off when you're sitting on the toilet.
Pretty amazing you can pick up basic mmWave sensors for a few bucks on amazon, and mate them to an esp32 board which is another couple bucks. It's so much fun as a hobby!
32 port Tx (vertical pancake beams) x 16 port Rx (horizontal pancake), something like 60 by 30 degrees. the entire thing used FPGA transceivers as one-bit DAC/ADC, Complementary Golay Code waveforms with one-bit correlation in the FPGAs (two VCU128s) -- digital logic was essentially the same as a binarized neural network, I squeezed a ton of popcnt performance out of those chips using both DSPs and LUTs
It was designed for automotive as a replacement for LiDAR, also useful for finding metal FOD on runways, or concealed weapons and I suppose also liquids on travelers walking in an airport...
(Linked VCU128 digital radar was cool but even cooler is using them as digital array beamformers and sending RDMA over fiber into a quad A100s nvlinked to do the whole radar DSP pipeline)