Passive Wireless Electric Field Sensor Using RF Resonator
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Solution Overview
Problem
Current electric field measurement sensors for high voltage apparatus are either heavy, require external power, and are not passive or wireless, limiting their portability and safety in measuring high voltage AC electric fields.
Innovation Solution
A passive, wireless electric field sensor using an RF resonator loaded with varactors that is interrogated wirelessly, allowing for remote operation and fast sampling of resonance frequency changes induced by the electric field, eliminating the need for batteries and direct power attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical sensors are used for electric field measurement, then measurement safety and portability are improved, but device weight increases considerably
Solution Approach 1:
The patent replaces the mechanical/optical sensing system with an electromagnetic resonance-based sensing system. The resonator structure uses electromagnetic field coupling between inner and outer conductors to detect electric field changes, eliminating the need for heavy optical components while maintaining safety through non-contact measurement.
Solution Approach 2:
The patent changes the operating parameter from optical frequency to radio frequency (RF) resonance frequency. By tuning the resonator's natural frequency to match the electric field variations, the system achieves sensitive detection without requiring heavy optical transducers, thus reducing weight while maintaining measurement capability.
2Measurement precision
If optical sensors with external power source are used, then measurement capability is improved, but device complexity and installation requirements increase
Solution Approach 1:
The resonator structure is designed to be self-exciting through the coupling between the inner and outer conductors. The electric field itself provides the energy for resonance, eliminating the need for external power sources or complex installation infrastructure. The system measures the electric field by detecting its own resonant response.
Solution Approach 2:
The patent introduces an intermediary resonant structure that couples the electric field to the measurement system. The resonator acts as a mediator between the high voltage electric field and the measurement device, enabling precise measurement without direct contact or complex external power connections.
3Weight of moving object
If passive sensor structure is used, then device weight and complexity are reduced, but measurement range and sensitivity may be limited
Solution Approach 1:
The patent applies resonance principles where the resonator structure vibrates at its natural frequency when exposed to the electric field. This resonant vibration amplifies the measurement signal, enabling the lightweight passive structure to detect electric fields over an extended range with high sensitivity, overcoming the limitations of simple passive sensors.
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 lightweight, low-cost, and safe measurement of high voltage AC electric fields with extended interrogation distance and simultaneous measurement of multiple sensors, suitable for insulation defect detection and voltage profiling.
Implementation Method 1
the capacitance of the resonator changes in response to a shift in its resonance frequency caused by a change in the reverse bias voltage of the varactors
Implementation Method 2
RF resonator loaded with varactors
Implementation Method 3
determining a resonance frequency of the sensor; receiving an RF ring back signal from the sensor
Implementation Method 4
a coaxial connector on the outer cylinder for coupling to an antenna for receiving a wireless signal wherein the wireless signal comprising RF pulses
Data Source
AI summary
A new passive wireless electric field sensor is disclosed. This sensor does not require direct attachment to a source of power which makes it passive. It is composed of a resonator loaded with varactors. The sensor is interrogated by a remotely located device transmitting and receiving the pulses of sine wave in the resonance frequency range of the sensor. Therefore, the sensor can be mounted in the vicinity of high voltage apparatus and interrogated from a safe distance.