Dual Magnetic Electric Field Quartz Sensor
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Solution Overview
Problem
Traditional wire-based antennas have low efficiency for wavelengths larger than their physical size, and existing magnetostrictive sensors cannot simultaneously detect magnetic and electric fields with comparable sensitivities or determine the propagation direction and polarization of RF waves effectively.
Innovation Solution
A RF antenna with a magnetostrictive film on a quartz MEMS resonator that selectively detects electric and magnetic fields along orthogonal axes, using transimpedance and high impedance amplifiers to filter and separate the signals, allowing for the determination of RF wave direction and polarization with two orthogonally disposed resonators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wire-based antennas are used for wavelengths larger than their physical size, then the antenna structure is simple, but the efficiency is very low due to large reactance and low radiation resistance
Solution Approach 1:
The patent replaces traditional electromagnetic wire-based antenna structures with a magnetostrictive-acoustic resonance system. The magnetostrictive film converts electromagnetic fields to acoustic vibrations in the quartz resonator, which then generates electrical signals. This mechanical/acoustic substitution enables efficient operation at wavelengths much larger than the physical device dimensions, resolving the efficiency limitation of conventional antennas.
Solution Approach 2:
The patent operates the quartz resonator at its mechanical resonance frequency, where the acoustic wavelength is much smaller than the electromagnetic wavelength. This parameter transformation allows the same physical structure to achieve high efficiency for electromagnetic wavelengths hundreds of times larger than the device size, fundamentally changing the scaling relationship between antenna size and operating wavelength.
2Measurement precision
If magnetostrictive sensors are used to detect magnetic fields, then magnetic field sensitivity is improved, but electric field detection capability is lost
Solution Approach 1:
The patent designs the magnetostrictive-quartz resonator system to perform multiple detection functions simultaneously. The same device structure detects both magnetic fields (through magnetostrictive effect) and electric fields (through piezoelectric effect in the quartz resonator), enabling dual-field sensing capability while maintaining high sensitivity for both modalities.
Solution Approach 2:
The patent combines magnetostrictive material with piezoelectric quartz in a composite structure. The magnetostrictive film responds to magnetic fields while the piezoelectric quartz resonator responds to electric fields and mechanical vibrations. This composite material approach enables simultaneous detection of both magnetic and electric field components with comparable sensitivities.
3Measurement precision
If multiple sensors are used to determine propagation direction and polarization, then measurement accuracy is improved, but device complexity and sensor quantity increase
Solution Approach 1:
The patent makes each magnetostrictive-quartz resonator sensor capable of providing multiple measurement functions simultaneously. By orienting the resonators along orthogonal axes and utilizing both magnetic and electric field detection capabilities, each sensor contributes to determining propagation direction, polarization, and field strength, reducing the total number of sensors needed while maintaining measurement accuracy.
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 antenna achieves high sensitivity and efficiency in detecting both magnetic and electric fields, enabling the determination of RF wave direction and polarization with reduced sensor size and complexity.
Implementation Method 1
The conversion of an electromagnetic wave to an acoustic signal is accomplished through a combination of a magnetostrictive material added to a piezoelectric element, thus converting the magnetic field energy to strain energy
Implementation Method 2
converting the magnetic field energy to strain energy and then strain into a voltage in the piezoelectric element
Implementation Method 3
The electric field can produce the highest voltage across the plates at the antiresonance (high impedance frequency) of the resonator when connected to a high impedance load
Implementation Method 4
the magnetic field can produce the highest voltage across the plates at the series resonance (low impedance of the resonator) when driving a low impedance amplifier
Implementation Method 5
the Radio Frequency (RF) signal is converted to an acoustic signal with a much smaller wavelength than the original signal due to a much slower acoustic velocity in materials compared to the speed of light
Data Source
AI summary
A RF field sensor in which a magnetostrictive film is deposited on one or more electrodes of one or more quartz resonator(s) in which an electric field of the RF field is detected along one axis of the RF field sensor and a magnetic field of the RF field is detected along an orthogonal axis of the RF field sensor simultaneously.