LAUSR

Receiver coils in embedded microsensors are small and their transmitters are unpredictably distant and misaligned, so available power is low and variable. The 180-nm, 6.78-MHz switched resonant half bridge here, however, only uses two transistors with a transfer rate and duration that are both adjustable. This way, the prototype outputs 13%–85% of the 9.7–1580 ${\mu }\text{W}$ that a 54.1-mm² receiver coil avails when 13 to 38 mm from its source. This is up to 38% more power and with 25% smaller footprint than the best comparable receiver.