SMR Magnetoelectric Antenna With Bragg Reflector Acoustic Isolation
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Solution Overview
Problem
Mechanically driven antennas, particularly those based on magnetoelectric (ME) structures, face challenges due to fragility and energy loss issues, especially in solidly mounted resonator (SMR) structures which require effective acoustic isolation to prevent energy leakage and withstand external collisions.
Innovation Solution
A solidly mounted resonator (SMR)-based ME antenna is designed with a Bragg reflector comprising alternating layers of high and low acoustic impedance materials, coupled with a magnetostrictive/piezoelectric composite element and electrically conductive contacts for impedance matching, to reduce energy loss and enhance mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If FBAR structure with air gap is used for acoustic isolation, then energy leakage is reduced, but mechanical fragility increases due to suspended structure and fragile anchors
Solution Approach 1:
The device is segmented into distinct functional layers: piezoelectric layer for acoustic resonance, magnetostrictive layer for magnetic coupling, and substrate for mechanical support. This segmentation allows the resonating elements to be small and acoustically isolated while the substrate provides robust mechanical support, resolving the contradiction between energy confinement and mechanical fragility
Solution Approach 2:
The magnetostrictive layer is nested within or adjacent to the piezoelectric layer, creating a compact heterostructure. This nested configuration allows the acoustic resonance to be confined in a small volume while the integrated structure provides mechanical strength, eliminating the need for fragile suspended anchors
2Reliability
If SMR structure with Bragg reflector is used, then mechanical robustness is improved by eliminating suspended structures, but acoustic energy confinement becomes more challenging without air gap
Solution Approach 1:
The magnetostrictive layer acts as an intermediary between the piezoelectric acoustic resonator and the substrate. It provides a mechanically robust connection while its magnetic properties enable non-contact actuation and sensing, allowing acoustic energy confinement without requiring an air gap or fragile anchors
Solution Approach 2:
The device uses a composite heterostructure combining piezoelectric and magnetostrictive materials. This composite structure provides both acoustic resonance functionality and mechanical robustness, as the magnetostrictive layer can be integrated directly with the substrate without requiring suspended configurations
3Volume of moving object
If antenna size is reduced to one-thousandth of wavelength using electromechanical resonance, then miniaturization is achieved, but structural fragility increases
Solution Approach 1:
The antenna is segmented into thin-film layers deposited on a substrate, allowing the resonating mass to be minimized for miniaturization while the substrate provides the mechanical strength. This segmentation enables the antenna to be much smaller than traditional wavelengths while avoiding structural fragility
Solution Approach 2:
The patent replaces traditional mechanical support structures (such as fragile anchors and suspended membranes) with a substrate-integrated approach. The magnetostrictive layer provides mechanical coupling to the substrate, eliminating the need for fragile mechanical support elements and enabling miniaturization without compromising structural integrity
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 SMR-based ME antenna effectively confines acoustic energy, reducing energy loss and improving mechanical robustness, resulting in enhanced radiation patterns and power handling capabilities compared to traditional FBAR antennas.
Implementation Method 1
magnetostrictive/piezoelectric heterostructure rely on electromechanical resonance
Implementation Method 2
magnetostrictive/piezoelectric heterostructure rely on electromechanical resonance
Implementation Method 3
The energy leakage is largely prohibited by the reflection of acoustic waves at each interface of the multilayer stack due to the acoustic impedance mismatch
Implementation Method 4
This Bragg reflector comprises alternating layers of low and high acoustic impedance materials
Implementation Method 5
magnetoelectric (ME) antennas based on a released magnetostrictive/piezoelectric heterostructure rely on electromechanical resonance
Data Source
AI summary
A solidly mounted resonator (SMR)-based magnetoelectric (ME) antenna comprises a substrate, a Bragg reflector disposed on the substrate, a magnetostrictive/piezoelectric ME composite element disposed on the Bragg reflector, a first electrically conductive contact and a second electrically conductive contact. The first contact is disposed between the Bragg reflector and the magnetostrictive/piezoelectric ME composite element and electrically coupled to a bottom surface of the magnetostrictive/piezoelectric ME composite element. The second contact is disposed on top of the magnetostrictive/piezoelectric ME composite element and electrically coupled to the top of the magnetostrictive/piezoelectric ME composite element. The magnetostrictive/piezoelectric ME composite element comprises a magnetorestrictive multilayer deposited on a piezoelectric layer. The magnetorestrictive multilayer produces an in-plane uniaxial magnetic anisotropy (UMA). The UMA is a twofold UMA that exhibits a symmetric radiation pattern.