  In this paper, we expand upon a new metric called the Waste Factor ($W$), a
mathematical framework used to evaluate power efficiency in cascaded
communication systems, by accounting for power wasted in individual components
along a cascade. We show that the derivation of the Waste Factor, a unifying
metric for defining wasted power along the signal path of any cascade, is
similar to the mathematical approach used by H. Friis in 1944 to develop the
Noise Factor ($F$), which has since served as a unifying metric for quantifying
additive noise power in a cascade. Furthermore, the mathematical formulation of
$W$ can be utilized in artificial intelligence (AI) and machine learning (ML)
design and control for enhanced power efficiency. We consider the power usage
effectiveness (PUE), which is a widely used energy efficiency metric for data
centers, to evaluate $W$ for the data center as a whole. The use of $W$ allows
easy comparison of power efficiency between data centers and their components.
Our study further explores how insertion loss of components in a cascaded
communication system influences $W$ at 28 GHz and 142 GHz along with the data
rate performance, evaluated using the consumption efficiency factor (CEF). We
observe CEF's marked sensitivity, particularly to phase shifter insertion loss
changes. Notably, CEF variations are more prominent in uplink transmissions,
whereas downlink transmissions offer relative CEF stability. Our exploration
also covers the effects of varying User Equipment (UE) and Base Station (BS)
deployment density on CEF in cellular networks. This work underscores the
enhanced energy efficiency at 142 GHz, compared to 28 GHz, as UE and BS numbers
escalate.
