In this paper, we argue that phased array WPT systems can
have advantages in terms of system efficiency and minimal
leakage fields if the phased array system is designed and implemented
properly. Proper design and implementation requires a
rigorous understanding of the circuits and controllable parameters
for a phased array WPT system. We provide a thorough
analysis of a generalized multiple transmitter, multiple receiver
phase-synchronized WPT system that can be used to quickly
simulate complex networks of wireless power transmitters and
receivers. We expand on this analysis and demonstrate simulation
results for three and four Tx coil phased arrayWPT systems.
The remainder of the paper focuses on a three-element system,
consisting of two Tx coils and one Rx coil. We define
critical parameters that allow the user to directly compute the
magnitude and phase that either maximizes or minimizes power
delivered to the load. After experimentally validating these equations
and simulation results, we highlight some additional capabilities
of a phased array WPT system in comparison to a
standard single Tx coil configuration. The adjacent phased array
configuration achieves highest system efficiency, which includes
the PA efficiency on the transmitter side and rectifier
efficiency on the receive side. However, the overlapping configuration
results in lowest leakage fields behind the Tx coils,
and consequently the highest FOM for the best balance between
high efficiency and lowleakage fields. Finally, we present a fully
autonomous system capable of adapting to variations in distance
between the Tx and Rx coils while automatically controlling the
magnitude and phase of the transmitter to maintain maximum
system efficiency.