Loop-Gap Resonator with Elongated Lead for EPR-NMR Sensitivity
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Solution Overview
Problem
Traditional electron-nuclear double resonance systems face limitations in detection sensitivity due to the shielding effect of loop-gap resonators on radio-frequency fields and poor microwave field distribution, especially when dealing with liquid samples of high dielectric constant, which reduces the fill factor and overall sensitivity.
Innovation Solution
The integration of a radio-frequency coil and microwave resonator into a single structure using multiple loop-gap resonators with elongated leads, reducing the diameter of the radio-frequency coil and improving the fill factor, and enhancing the distribution of the microwave magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional metallic resonant cavity is used, then the Q value is high, but it is not suitable for pulse microwave excitation and cannot be used for liquid samples with high dielectric constant due to large size and poor fill factor
Solution Approach 1:
The patent changes the resonator structure from traditional metallic cavity to loop-gap resonator configuration, fundamentally altering the electromagnetic field distribution parameters. This enables the resonator to achieve both high Q value and suitability for pulse microwave excitation by modifying the resonant mode and field confinement characteristics
Solution Approach 2:
The resonator is divided into distinct loop-gap structures with separate regions for microwave resonance and radio-frequency coil placement. This segmentation allows independent optimization of microwave field confinement (for high Q) and radio-frequency field access (for sample insertion and coil positioning)
2Object-affected harmful factors
If the radio-frequency coil diameter is increased to shield the loop-gap resonator, then the shielding effect is reduced, but the fill factor is greatly reduced
Solution Approach 1:
The patent extracts the radio-frequency coil from the traditional external solenoid configuration and integrates it directly into the loop-gap resonator structure. This extraction eliminates the need for large shielding coils while maintaining effective decoupling between microwave and radio-frequency fields through the inherent geometry of the integrated structure
Solution Approach 2:
The radio-frequency coil is merged with the loop-gap resonator structure, forming an integrated unit where the coil windings are positioned within or along the resonator loops. This merging achieves both shielding functionality and high fill factor by utilizing the same structural space for dual purposes
3Object-affected harmful factors
If silver plating is performed on quartz glass surface to reduce shielding effect, then the shielding is reduced, but the structure complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs composite construction combining conductive materials (for resonator loops and coil windings) with dielectric materials (for support structures and sample positioning). This composite approach achieves electromagnetic shielding and field confinement through geometric configuration and material properties rather than requiring complex surface treatments like silver plating
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
This configuration increases the detection sensitivity of the system, improves microwave field distribution, and is more suitable for pulse microwave excitation, addressing the limitations of traditional metallic resonators.
Implementation Method 1
B1 is used for exciting nuclear magnetic resonance
Implementation Method 2
B2 is used for exciting electron spin resonance
Implementation Method 3
cylindrical loop-gap resonator... structure of such resonator may greatly improve the distribution of a microwave magnetic field
Data Source
AI summary
An electron-nuclear double resonance resonator, having a loop-gap resonator and an elongated lead; the loop-gap resonator comprises a plurality of arc-shaped conductive plates, and the elongated lead connects the arc-shaped conductive plates into a radio-frequency coil; the loop-gap resonator resonates at an electron resonance frequency, and the radio-frequency coil resonates at a nuclear resonance frequency; with the structure of the loop-gap resonator, the separation between an electric field and a magnetic field can be accelerated to ensure the maximization of the ratio of the magnetic field to the electric field inside a resonant resonator; and with the elongated lead, the impact of the lead to a resonance frequency and the mode of the loop-gap resonator is prevented as much as possible, and meanwhile the conductive plates of the loop-gap resonator can be connected into the radio-frequency coil.