Hybrid RFID Tag Optical Clock Extraction
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Solution Overview
Problem
Conventional RFID tag devices face challenges in achieving a small footprint due to the need for separate antennas for transmit and receive modes, complex circuitry like PLLs and VCOs, and battery power, which becomes impractical as integration area decreases, leading to mutual coupling and interference issues.
Innovation Solution
Implementing a hybrid framework with an optical transmitter/receiver system and an RF transmitter/receiver system, where the RFID tag device extracts clock signals from optical signals and generates a regulated supply voltage, eliminating the need for on-chip batteries and complex clock generation circuitry, and using magnetic coupling for wireless communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional RFID tag devices use separate antennas for transmit and receive modes, then communication functionality is achieved, but the integration area increases significantly
Solution Approach 1:
The patent combines the transmit and receive antenna functions into a single antenna structure. The antenna can operate in transmit mode by receiving RF energy from the reader and converting it to optical signals, and in receive mode by detecting optical signals from the reader. This merging of functions eliminates the need for separate antennas and reduces the overall integration area significantly.
Solution Approach 2:
The single antenna is designed to perform multiple functions: it serves as both a transmit antenna and a receive antenna, and also functions as an optical receiver. This multi-functionality allows the antenna to replace what would traditionally require two separate antenna systems, thereby reducing the footprint while maintaining full communication capability.
2Ease of operation
If RFID tag devices use PLLs and VCOs for clock signal generation, then clocking functions are achieved, but device complexity and area increase
Solution Approach 1:
The patent extracts the clock signal generation function from the traditional RF domain and relocates it to the optical domain. Instead of using on-chip PLLs and VCOs to generate clock signals, the system receives optical signals from the reader that contain embedded clock information. This extraction eliminates the need for complex clock generation circuitry while maintaining proper clocking functionality.
Solution Approach 2:
The optical signal acts as an intermediary carrier that transports both data and clock information from the reader to the tag. By using the optical signal as a mediator, the system avoids the need for on-chip clock generation circuitry, reducing complexity while maintaining operational functionality.
3Area of stationary object
If RFID tag devices decrease in size, then footprint is reduced, but mutual coupling and interference between antennas increase
Solution Approach 1:
The patent substitutes the traditional RF-based antenna system with an optical communication system. Instead of using two separate RF antennas that would cause mutual coupling at close distances, the system uses a single antenna that communicates optically with the reader. This substitution eliminates the mutual coupling problem inherent in proximity-based RF antenna systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the development of RFID tag devices with high integration density and small footprint, operating autonomously without batteries and complex circuitry, reducing mutual coupling and interference, and allowing for efficient data transmission.
Implementation Method 1
The optical receiver circuitry is configured to receive an optical signal having an embedded clock signal from an interrogator device, and convert the optical signal into an electrical signal comprising the embedded clock signal
Implementation Method 2
The voltage regulator circuitry configured to generate a regulated supply voltage from the electrical signal, wherein the regulated supply voltage is utilized as a bias voltage for components of the tag device
Implementation Method 3
The data transmitter circuitry is configured to wirelessly transmit tag data to the interrogator device
Implementation Method 4
The receiver circuity is configured to (i) apply an unmodulated radio frequency carrier signal to the antenna, (ii) detect changes in amplitude of an amplitude modulated backscattered radio frequency carrier signal which is reflected from the tag device and captured on the antenna
Data Source
AI summary
RFID (radio frequency identification) systems are provided in which tag and interrogator devices implement a hybrid framework for signaling including an optical transmitter/receiver system and an RF transmitter/receiver system. For instance, an RFID tag device includes: optical receiver circuitry configured to receive an optical signal having an embedded clock signal from an interrogator device, and convert the optical signal into an electrical signal comprising the embedded clock signal; clock extraction circuitry configured to extract the embedded clock signal from the electrical signal, and output the extracted clock signal as a clock signal for controlling clocking functions of the tag device; voltage regulator circuitry configured to generate a regulated supply voltage from the electrical signal, 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.