https://ieeexplore.ieee.org/document/10073945

2x2 dual-band dual-polarization multiple input multiple output (MIMO) stacked patch antennas connected to a 4x1 wideband beamformer chip.

28 GHz / 39 GHz

12-layer printed circuit board (PCB) to reduce cost. Separate patch antennas for each band for wider bandwidth instead of using stubs, slots or pins for a dual-band patch. SiGe BiCMOS beamformer has all RF pads on one side for minimum antenna routing.

5G FR2 cellular devices

Effective isotropic radiated power (EIRP) is 27-30 dBm; 3dB BW is 26.5-29 GHz, 36-40 GHz Scan is ±40° at 28 GHz, ±30°-40° at 39 GHz Error vector magnitude (EVM) <5%