Hybrid tag for radio frequency identification system

A tag device, comprising:

• a substrate comprising a plurality of components integrally formed thereon, wherein the components comprise:
• state machine control circuitry configured to control functions of the tag device;
• a non-volatile memory configured to store tag data;
• optical receiver circuitry configured to receive a pulsed optical signal having an embedded clock signal from an interrogator device, and convert the pulsed optical signal into an electrical signal which represents the embedded clock signal within the pulsed optical signal which is optically transmitted from the interrogator device to control clocking functions of the tag device;
• clock extraction circuitry configured to extract the embedded clock signal from the electrical signal output from the optical receiver circuitry, and output the extracted clock signal as a clock signal for controlling the clocking functions of the tag device;
• voltage regulator circuitry configured to generate a regulated supply voltage from the electrical signal output from the optical receiver circuitry, wherein the regulated supply voltage is utilized as a bias voltage for components of the tag device;
• and
• data transmitter circuitry configured to wirelessly transmit tag data to the interrogator device;
• wherein the clock signal is input to the state machine control circuitry to control a memory access operation of the non-volatile memory, wherein the memory access operation comprises reading out the stored tag data as a serial data bit stream that is serially clocked to the data transmitter circuitry using the clock signal;
• wherein the data transmitter circuitry comprises:
• a loop antenna;
• and
• switching circuitry that is configured to change an impedance of the loop antenna in response to the serial data bit stream which comprises the tag data that is read out from the non-volatile memory;
• wherein the switching circuitry is configured to change the impedance of the loop antenna by selectively connecting and disconnecting the loop antenna to a ground terminal, based on logic levels of the data bits in the serial data bit stream applied to the switching circuitry;
• wherein the loop antenna on the tag device is configured to magnetically couple RF power from an unmodulated RF carrier signal applied to an RF antenna of the interrogator device;
• and
• wherein changing the impedance of the loop antenna modulates the RF power on the loop antenna and causes modulated RF power encoded with the serial data bit stream to be reflected back to the RF antenna of the interrogator device.