Hybrid Light RF Rectifier Circuit for Energy Harvesting Efficiency
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Solution Overview
Problem
Conventional light energy and RF energy harvesting circuits face inefficiencies due to varying light source brightness and low RF energy conversion efficiency, especially in indoor conditions and with low RF energy density, leading to limited energy acquisition and safety concerns.
Innovation Solution
A light energy and RF energy harvesting rectifier circuit that combines both energy sources using an injection-locked oscillating circuit to enhance conversion efficiency, where the circuit locks oscillation frequency with RF frequency and includes diode and switch rectifiers, low pass filters, and voltage-multiplying circuits to optimize energy output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If solar-cell panels are used for light energy harvesting, then direct current can be generated from sunlight, but conversion efficiency drops sharply in indoor conditions with insufficient sunlight
Solution Approach 1:
The patent combines light energy harvesting and RF energy harvesting into a single hybrid system. The light energy receiver (solar cell) and RF energy receiver (antenna) are integrated with a shared rectifier circuit and power management unit, allowing the system to simultaneously capture both light energy and RF energy from the environment, thereby maintaining energy harvesting capability across varying light conditions.
Solution Approach 2:
The rectifier circuit is designed to handle multiple energy sources universally. It can process rectification for both light energy (from solar cell) and RF energy (from antenna) through the same circuit architecture, making the system adaptable to different energy availability scenarios without requiring separate dedicated circuits for each energy source.
2Reliability
If inductive switch-type rectifier circuit is used with solar-cell panel, then rectification can be achieved, but considerable volume and construction cost are required due to discrete choke coil elements
Solution Approach 1:
The patent removes the discrete choke coil element from the rectifier circuit architecture. Instead of using an inductive switch-type rectifier that requires a physical choke coil, the invention employs a capacitor-based hold circuit that extracts the inductive component entirely, significantly reducing the circuit volume while maintaining rectification functionality.
Solution Approach 2:
The patent replaces the inductive (magnetic field-based) rectification mechanism with a capacitive (electric field-based) hold circuit. This substitution eliminates the need for magnetic core components like choke coils, reducing both volume and construction complexity while achieving the same rectification effect through voltage holding capability of capacitors.
3Loss of energy
If high-power energy transmitter is used to improve RF conversion efficiency, then RF to DC conversion efficiency increases, but safety concerns arise from high-power electromagnetic wave radiation
Solution Approach 1:
The system harvests RF energy passively from the ambient environment without requiring an active high-power transmitter. The RF energy receiver (antenna) captures naturally occurring RF signals from the surroundings, and the rectifier circuit converts them directly to DC. This self-service approach eliminates the need for external high-power transmission, thereby resolving safety concerns while maintaining energy harvesting functionality.
4Device complexity
If single environmental energy source is used for energy harvesting, then circuit design is simplified, but energy demand cannot be met due to limited energy availability
Solution Approach 1:
The patent merges light energy harvesting and RF energy harvesting into a unified hybrid system. Both energy sources feed into a common rectifier and power management circuit, allowing the system to accumulate energy from multiple environmental sources simultaneously, thereby meeting higher energy demands that would be impossible with a single energy source alone.
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
This approach allows for simultaneous harvesting of light and RF energy, improving overall energy conversion efficiency and enabling continuous energy harvesting even with insufficient light sources by switching to conventional RF mode.
Implementation Method 1
photoelectric conversion, which converts light energy to electrical energy by using solar-cell panels
Implementation Method 2
RF energy may be obtained easily and may be safer operation for human in the modern society
Data Source
AI summary
The invention presents a rectifier circuit and a rectification method for harvesting light energy and RF energy, which uses light energy receiver to convert light energy into input direct-current voltage and RF energy receiver to convert RF energy into RF voltage simultaneously. Also, by combining with injection-locked oscillating circuit, oscillating frequency of injection-locked oscillating circuit is locked according to RF frequency also amplitude of RF voltage is enhanced. By using rectifier circuit to rectify and output corresponding output direct-current voltage, both light energy and RF energy may be harvested simultaneously and energy conversion efficiency is enhanced.