LOCAL OSCILLATOR FREQUENCY-BASED PROXIMITY SENSOR

A battery-less Interest of things (IoT) tag integrated with a proximity sensor is disclosed. The battery-less IoT tag includes: a transmit antenna designed to have an inductive element; an integrated circuit having a capacitive element; and an energy harvester coupled to a capacitor, wherein the capacitor is an on-die capacitor and the harvester is configured to harvest energy from ambient signals, wherein the inductive element and the capacitive element form the proximity sensor oscillating at a local oscillator (LO) frequency, and wherein a frequency offset from the LO frequency is indicative of a detection of a nearby object.