MBMC Rectenna Circuit for Multi-Band RF Energy Harvesting
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Solution Overview
Problem
Conventional rectennas are limited by their single-frequency band operation, leading to inefficient RF energy conversion and increased space and cost, with existing multi-frequency designs using multiple antennas and rectifiers, and they suffer from low power conversion efficiency at varying input power levels due to breakdown voltage limitations.
Innovation Solution
A multi-band multi-channel (MBMC) RF matching network and an extended input power range rectifier, including an adaptively reconfigurable or breakdown-protected rectifier, which uses T-shaped transmission line matching structures and transistor-protected diode structures to enhance impedance matching and power conversion efficiency across multiple frequency bands and power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-frequency band rectenna is used, then the device complexity is reduced, but the adaptability to multiple frequency bands deteriorates
Solution Approach 1:
The patent implements a universal rectenna structure that can operate across multiple frequency bands (e.g., 900 MHz, 1.8 GHz, 2.1 GHz) using a single antenna and rectifier combination. The matching network is designed with multiple T-shaped transmission line sections that can simultaneously match impedances for different frequency bands, allowing the same hardware to harvest energy from various RF sources without requiring separate rectennas for each band.
Solution Approach 2:
The matching network is divided into multiple T-shaped transmission line segments, each configured for specific frequency bands. These segmented structures can be independently optimized for different frequencies while working together as an integrated system, enabling broad frequency coverage without proportionally increasing overall complexity.
2Adaptability or versatility
If multiple antennas and rectifiers are used for multi-frequency operation, then the adaptability to multiple frequency bands is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple frequency handling functions into a single antenna and a single rectifier system. Instead of using separate antenna-rectifier pairs for each frequency band, the invention combines these components into one integrated structure with a multi-band matching network, thereby reducing the total number of components while maintaining multi-frequency capability.
Solution Approach 2:
The single rectenna system is designed to universally handle multiple frequency bands through the matching network configuration, eliminating the need for multiple specialized rectenna units and reducing system complexity.
3Power
If the input RF power exceeds the breakdown voltage of the diode, then the rectifier can handle higher power levels, but the power conversion efficiency degrades rapidly
Solution Approach 1:
The patent employs dynamic switching mechanisms that automatically adjust the rectifier configuration based on the input power level. At low power levels, the rectifier operates in a high-efficiency mode with optimal impedance matching. When power levels increase approaching breakdown voltage, the system dynamically switches to a different operating configuration that protects the diode while maintaining acceptable efficiency, thus adapting to varying power conditions.
Solution Approach 2:
The system changes operating parameters such as impedance values and circuit topology based on input power levels. By adjusting these parameters dynamically, the rectifier maintains high conversion efficiency across a wide power range while preventing diode breakdown through controlled operation below the breakdown threshold.
4Power
If series diodes are added to extend breakdown voltage, then the power handling capability is improved, but the power conversion efficiency at low input power deteriorates
Solution Approach 1:
Instead of using a fixed series diode configuration, the patent implements a dynamic switching system that selects between different diode arrangements based on input power levels. At low power levels, the system uses a configuration optimized for efficiency (fewer or no series diodes). At higher power levels, it dynamically switches to a configuration with series diodes to extend breakdown voltage, thus optimizing performance for each operating condition.
Solution Approach 2:
The system changes the effective breakdown voltage parameter by reconfiguring the diode connections according to input power levels, maintaining high efficiency across the full power range rather than being constrained by a fixed high breakdown voltage configuration.
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
The solution enables enhanced RF-to-DC power conversion efficiency across a wider range of input power conditions and multiple frequency bands, improving the efficiency and cost-effectiveness of wireless power transmission and ambient RF energy harvesting.
Implementation Method 1
a multi-band multi-channel (MBMC) RF matching network... which uses T-shaped transmission line matching structures to enhance impedance matching and power conversion efficiency
Implementation Method 2
an extended input power range rectifier, including an adaptively reconfigurable or breakdown-protected rectifier, which uses T-shaped transmission line matching structures and transistor-protected diode structures
Implementation Method 3
breakdown-protected rectifier... transistor-protected diode structures to enhance impedance matching and power conversion efficiency across multiple frequency bands and power levels
Data Source
AI summary
A rectenna includes (a) a multi-band multi-channel (MBMC) matching network, and/or (b) an adaptively reconfigurable rectifier or a breakdown-protected rectifier. An MBMC matching network includes a plurality of T-shaped transmission line matching structures coupled in series. An adaptively reconfigurable rectifier circuit includes a low input power rectifying portion, a high input power rectifying portion, and a set of transistors configured for selectively and automatically transitioning the adaptively reconfigurable rectifier between a low input power operating configuration and a high input RF power operating configuration, in a manner correlated with input RF power level. A breakdown-protected rectifier includes a transistor-protected diode structure having a diode coupled to a transistor in a manner that protects the diode from direct exposure to negative voltages that would ordinarily cause the diode to break down in the absence of the transistor.