  Sub-terahertz (sub-THz) antenna array architectures significantly impact
power usage and communications capacity in multi-user multiple-input
multiple-output (MU-MIMO) systems. In this work, we compare the energy
efficiency and spectral efficiency of three MU-MIMO capable array architectures
for base station receivers. We provide a sub-THz circuits power analysis, based
on our review of state-of-the-art D-band and G-band components, and compare
communications capabilities through wideband simulations. Our analysis reveals
that digital arrays can provide the highest spectral efficiency and energy
efficiency, due to the high power consumption of sub-THz active phase shifters
or when SNR and system spectral efficiency requirements are high.
