RF Energy Harvesting Circuit Passive Interface High Resistance
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Solution Overview
Problem
Conventional radio-frequency energy harvesting circuits are ineffective at low reception levels, failing to supply power to active components and limiting the range of wireless power supply systems to less than 10 meters, as they require sufficient energy to operate maximum power point tracking circuits.
Innovation Solution
A radio-frequency energy harvesting circuit with a passive interface circuit featuring a high-value static resistive load greater than 400 kΩ in series between the RF/DC converter and the energy storage capacity, enhancing sensitivity and allowing charging at low energy levels while protecting against overcurrent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a passive interface circuit with high-value resistive load is used, then sensitivity at low energy levels is improved, but charging speed and power transmission are reduced
Solution Approach 1:
The patent changes the load resistance parameter to a high value (greater than 400 kΩ) in the passive interface circuit. This parameter change enables the circuit to operate at low RF energy levels by matching the high impedance of the RF/DC converter, thereby improving sensitivity without requiring active components that would consume power.
2Power
If active components are used in the interface circuit, then power maximization is improved, but energy consumption increases
Solution Approach 1:
The patent extracts and removes the active components (MPPT circuit and DC/DC boost converter) from the interface circuit, replacing them with a passive circuit consisting of a high-value resistive load. This extraction eliminates the energy consumption associated with operating active components while maintaining the essential function of interfacing the RF/DC converter with the storage capacity.
3Loss of energy
If impedance matching circuit is added, then power transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the impedance matching function into the passive interface circuit by using the high-value resistive load to simultaneously achieve impedance matching and power transfer. This combining of functions avoids adding separate impedance matching components, thereby maintaining simplicity while improving power transfer efficiency at low energy levels.
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 charging at lower radio-frequency energy levels, increasing the range of wireless power supply systems beyond 10 meters and protecting against overcurrent, albeit at the cost of reduced charging speed and maximized power transmission.
Implementation Method 1
an antenna 21 suitable for receiving the radio-frequency energy
Implementation Method 2
a converter suitable for converting the radio-frequency energy received into a direct current electrical voltage, said RF/DC converter 23
Implementation Method 3
a passive interface circuit 24 including a resistive load 240 of high value, that is to say greater than 400 kilo-ohms (400 kΩ), arranged in series between an output port 231 of the RF/DC converter 23 and the electrical energy storage capacity 25
Data Source
AI summary
A radio-frequency energy harvesting circuit includes an antenna suitable for receiving the radio-frequency energy, a converter suitable for converting the radio-frequency energy received into a direct current electrical voltage, the “RF/DC converter”, an electrical energy storage capacity and an interface circuit arranged between an output port of the RF/DC converter and the electrical energy storage capacity. The interface circuit is a passive electrical circuit including a resistive load placed in series between the output port of the RF/DC converter and the electrical energy storage capacity, the resistive load being of static value equal to or greater than 400 kilo-ohms.