Power-Dependent Reactance Tuning for Energy Harvesting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Energy harvesting from wireless signals, particularly in IoT devices like C-RFID tags and battery-less sensors, faces challenges due to impedance mismatches between antennas and converter circuits, leading to reduced power conversion efficiency and readability issues, especially at varying power levels and distances.
Innovation Solution
The solution involves varying the reactance characteristic of the input converter circuit based on the power characteristic of the wireless signal to compensate for impedance mismatches between the antenna and the converter circuit, using components like MOSFETs and varactors to adjust capacitance and inductance, thereby improving power conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the antenna is directly connected to the converter circuit with fixed impedance, then the device structure is simple, but power conversion efficiency deteriorates due to impedance mismatch at varying power levels
Solution Approach 1:
The patent applies dynamics by making the impedance matching network adjustable rather than fixed. The reactance characteristic is varied based on the power characteristic of the wireless signal, allowing the system to adapt to different operating conditions. This dynamic adjustment resolves the contradiction by enabling high efficiency across varying power levels while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent changes the reactance parameter of the input converter circuit based on the power level of the received wireless signal. By adjusting the reactance characteristic to match the antenna impedance at different power levels, the system maximizes power conversion efficiency. This parameter change approach directly addresses the efficiency loss due to impedance mismatch.
2Reliability
If the impedance is fixed for the converter circuit, then the device is easier to manufacture, but readability deteriorates at varying distances and power levels
Solution Approach 1:
The patent implements dynamic impedance matching where the reactance characteristic adjusts according to the received signal power level. This dynamic behavior ensures reliable communication and readability across varying distances and power levels, while the adjustment mechanism remains integrated into the converter circuit to minimize manufacturing complexity.
Solution Approach 2:
The system uses feedback from the power characteristic detection to adjust the reactance characteristic of the input converter circuit. This feedback mechanism ensures that the impedance matching is continuously optimized based on the actual operating conditions, improving readability and reliability without requiring complex external control systems.
3Power
If no impedance compensation is applied, then the device complexity is low, but power availability deteriorates at varying wireless signal strengths
Solution Approach 1:
The patent changes the reactance parameter of the input converter circuit based on the detected power characteristic of the wireless signal. This parameter adjustment ensures optimal power transfer and maximizes power availability across different signal strengths. The integrated nature of this adjustment keeps the overall device complexity manageable.
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 significantly enhances power conversion efficiency, allowing more power to be available for device operations and storage, even at varying wireless signal strengths, and addresses the issue of impedance mismatch, improving device performance and efficiency.
Implementation Method 1
processing circuits of such battery-less devices may be powered, at least in part, by radio frequency (RF) energy, light energy or acoustical energy, or a combination thereof, collected at the wireless and/or battery-less devices
Implementation Method 2
varying the reactance characteristic of an input to a converter circuit to compensate for an impedance mismatch between an antenna and the converter circuit
Data Source
AI summary
Subject matter disclosed herein may relate to wireless energy harvesting and may relate more particularly to power-dependent tuning at energy-harvesting devices.