Autonomous Battery-Free Microwave Communication via Energy Harvesting
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Solution Overview
Problem
Conventional battery-free contact-less wireless communication devices operating at low microwave frequencies face limitations in energy harvesting efficiency and compatibility with common devices like mobile phones and portable computers, which require larger antennas and operate at low data rates.
Innovation Solution
An autonomous battery-free microwave frequency communication device incorporating a capacitance, antenna, microwave energy harvesting system, and a microwave frequency transceiver that generates and transmits its own carrier signal, enabling bi-directional communication with devices using standard protocols like Wi-Fi or Bluetooth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional near-field communication systems use inductive coupling at 13.56 MHz, then battery-free operation is achieved, but data transmission rate is limited to 848 kbps or less
Solution Approach 1:
The patent changes the operating frequency parameter from conventional 13.56 MHz to microwave frequencies (2.4 GHz and 5 GHz), enabling both higher data transmission rates and improved energy harvesting efficiency through the use of capacitively coupled energy harvesting circuits resonant at these higher frequencies
2Adaptability or versatility
If passive RFID tags use backscattering communication, then battery-free operation is achieved, but the tag must be in the near field of the reader
Solution Approach 1:
The passive tag incorporates an autonomous microwave frequency transceiver that can independently generate and transmit microwave frequency carrier signals, allowing the tag to initiate communication and operate beyond the near field of the reader without requiring continuous reader field presence
Solution Approach 2:
The system dynamically switches between energy harvesting mode and autonomous transmission mode, allowing the tag to harvest energy when in range and then autonomously transmit data when out of range, expanding effective communication distance
3Productivity
If microwave frequency communication uses autonomous carrier generation, then data transmission rate increases, but energy consumption increases
Solution Approach 1:
The system uses periodic energy harvesting intervals followed by autonomous transmission intervals, allowing the capacitance to recharge during energy harvesting phases and then power autonomous microwave transmissions during dedicated time windows, enabling high data rates while managing energy consumption
Solution Approach 2:
The system performs preliminary energy harvesting and storage in the capacitance before autonomous transmission is needed, ensuring sufficient energy is available to support high-rate microwave carrier generation and modulation without real-time power supply constraints
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 efficient energy harvesting and data transmission at microwave frequencies, allowing battery-free operation and compatibility with common devices, enhancing energy-harvesting efficiency and data transfer rates beyond conventional systems.
Implementation Method 1
a microwave energy harvesting system configured to harvest and store microwave energy received via the antenna onto the capacitance
Implementation Method 2
The microwave frequency transceiver is empowered by energy stored on the capacitance, and is configured to autonomously generate a microwave frequency carrier
Data Source
AI summary
An autonomous battery-free microwave frequency communication device which includes a capacitance, at least one antenna, a microwave energy harvesting system, a microwave frequency transceiver, and a control system. The energy harvesting system is configured to harvest and store microwave energy received via the antenna onto the capacitance. The transceiver is empowered by energy stored on the capacitance, and is configured to autonomously generate a microwave frequency carrier and to autonomously transmit information using the microwave frequency carrier according to a predetermined communications protocol via the antenna. The control system is empowered by energy stored on the capacitance, and is configured to provide information for transmission. Energy may be harvested from various communication forms, such as wireless network protocols or cellular communications. The frequency band from which energy is harvested may differ from the frequency band used for communications. The energy storage enables autonomous communications with external devices according to common or standard wireless communication protocols.