RF Energy Harvester Impedance Tuning for Dynamic Power Splitting
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Solution Overview
Problem
Existing RF energy harvesting systems face challenges in dynamically controlling RF power distribution, leading to increased size, cost, and complexity due to fixed power splits and the need for multiple antennas, which can result in interference and inefficiency.
Innovation Solution
An RF energy harvesting system incorporating an antenna, RF tuning network, and a load manipulator that transitions between configurations to change the input impedance of the RF energy harvester, allowing for dynamic control of RF power splitting by manipulating DC output properties, thereby directing or reflecting RF energy as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If RF switches are used to control power distribution, then power distribution control is achieved, but cost, size, and complexity increase
Solution Approach 1:
The patent removes the RF switch from the system entirely and replaces it with an impedance tuning network that directly controls power distribution by adjusting the reactive component. This extraction of the problematic component (RF switch) while maintaining the desired function (power control) resolves the contradiction between operational capability and system complexity.
Solution Approach 2:
The patent replaces the mechanical/electronic RF switch with an impedance tuning mechanism using reactive components (inductors and capacitors) that control power distribution through impedance matching rather than physical switching. This substitution eliminates the need for complex switch control circuitry while achieving the same power distribution function.
2Adaptability or versatility
If a passive RF tuning network is used to split power, then power splitting is achieved, but the power split is fixed and cannot be dynamically changed
Solution Approach 1:
The patent implements dynamic power splitting by making the impedance tuning network adjustable through control signals from a microcontroller. The reactive components (inductors and capacitors) can be dynamically reconfigured to change the impedance, thereby dynamically controlling the power split ratio between different loads without requiring multiple fixed networks.
Solution Approach 2:
The patent changes the electrical parameters (impedance, reactance) of the tuning network dynamically by adjusting the reactive components based on control signals. This allows the power split ratio to be varied continuously or in discrete steps, providing adaptability while maintaining system stability through controlled parameter adjustment.
3Adaptability or versatility
If multiple antennas are included to serve multiple harvesters, then more harvesters can receive energy, but overall size, cost, and complexity increase
Solution Approach 1:
The patent makes a single antenna serve multiple harvesters by using an impedance tuning network that can dynamically redirect RF energy to different loads. The same antenna and tuning network can serve different harvesters at different times or simultaneously with different power splits, eliminating the need for multiple dedicated antennas and reducing system size.
Solution Approach 2:
The patent merges the functions of multiple antennas into a single antenna system with a shared impedance tuning network. By combining the RF reception function and the power distribution function into one integrated system, the patent reduces the total number of components and overall system size while maintaining the capability to serve multiple harvesters.
4Adaptability or versatility
If multiple antennas are used, then multiple harvesters can be served, but interference between antennas occurs
Solution Approach 1:
The patent removes the source of interference by eliminating multiple antennas and their associated electromagnetic fields. Instead, it uses a single antenna with an impedance tuning network that electrically isolates different harvesters through impedance matching, preventing the mutual interference that would occur between multiple physically co-located antennas.
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 dynamic control of RF power distribution without the need for additional antennas or complex switches, reducing system size and cost while improving efficiency and enabling backscatter communication.
Implementation Method 1
The RF energy harvester can be operatively coupled to the RF tuning network and configured to receive an output of the RF tuning network and to produce a direct current (DC) output based on the received output of the RF tuning network
Implementation Method 2
The load manipulator can be coupled to an output of the RF energy harvester and configured to be transitioned between a first configuration and a second configuration to manipulate one or more properties associated with the RF energy harvester such that an input impedance of the RF energy harvester changes from a first input impedance to a second input impedance
Data Source
AI summary
In some embodiments, an apparatus includes an antenna; a radio-frequency (RF) tuning network configured to receive an input signal via the antenna; an RF energy harvester operatively coupled to the RF tuning network and configured to produce a direct current (DC) output based on the received output of the RF tuning network; and a load manipulator configured to be transitioned between a first configuration and a second configuration to manipulate one or more properties associated with the RF energy harvester such that an input impedance of the RF energy harvester changes from a first input impedance to a second input impedance. The first input impedance is associated with a first distribution of RF energy associated with the input signal relative to the RF energy harvester and the second input impedance is associated with a second distribution of RF energy associated with the input signal relative to the RF energy harvester.