Beamforming issue using ULA FMCW radar

Hello everyone,

I have created a MIMO FMCW radar with 3 transmit antennas and 4 receive antennas. I am currently simulating a radar scene in a free-space environment with 6 different targets, while all three transmit antennas operate simultaneously.

I would like to verify the usefulness of applying an analog beamformer (phase-shift beamforming) at the receiver. To do this, I compare the range-Doppler magnitude maps obtained from the 4 receive antennas without beamforming to those obtained when phase-shift beamforming is applied before amplification and dechirping.

However, regardless of the steering direction I choose — whether it corresponds to a target direction or not — the magnitude at each of the 4 receiver antennas remains higher in the case without beamforming than in the beamformed case.

Could someone help me understand why this happens, or point out what I might be missing in my implementation?

Thanks in advance for your help.

[George]

Hello - would you be able to share the code that is producing this unexpected result? I think it will be difficult to say what the issue is without some more information.