NMR Probe Resonant Circuit Transmission Line Length Optimization
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Solution Overview
Problem
Existing NMR probes produce minimal electric field strength at the center of the sample coil, leading to inadequate magnetic field uniformity and strength, which hinders the detection of NMR signals.
Innovation Solution
The NMR probe design includes a resonant circuit with a sample coil and transmission lines whose total length is set to specific values to maximize magnetic field strength at the center, allowing for uniform and intense magnetic field production by adjusting the transmission line lengths to satisfy equations such as Ln = λ + (n-1)λ/2, ensuring standing waves resonate at the desired RF frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the resonant circuit is designed to produce minimal electric field strength at the center of the sample coil, then the electric field minimal point is achieved, but the magnetic field strength and uniformity are insufficient for effective NMR signal detection
Solution Approach 1:
The patent changes the total transmission line length parameter to satisfy the equation Ln = λ + (n-1)λ/2, where λ is the wavelength and n is a positive integer. This parameter adjustment transforms the standing wave pattern to maximize magnetic field strength at the coil center while maintaining electric field minimization, thereby resolving the contradiction between reducing electric field interference and maximizing magnetic field strength for NMR detection
2Stability of the object's composition
If the transmission line length is adjusted to minimize electric field at the center, then electric field distribution is optimized, but the magnetic field uniformity and intensity are compromised
Solution Approach 1:
By adjusting the total transmission line length to satisfy Ln = λ + (n-1)λ/2, the patent simultaneously optimizes both electric field distribution and magnetic field uniformity. This parameter change creates a standing wave pattern where the magnetic field maximum coincides with the coil center, ensuring uniform magnetic field across the sample region while maintaining stable electric field distribution
3Object-affected harmful factors
If the resonant circuit produces minimal electric field strength at the center, then the electric field is minimized, but the NMR signal detection sensitivity is reduced
Solution Approach 1:
The patent changes the total transmission line length parameter to satisfy Ln = λ + (n-1)λ/2, which maximizes magnetic field strength at the coil center. Since NMR signal strength is directly proportional to the applied magnetic field intensity, this parameter change enhances NMR signal detection sensitivity while maintaining minimal electric field strength at the center, thus resolving the contradiction between electric field minimization and signal detection sensitivity
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 enables the production of an intense and uniform magnetic field within the sample coil, enhancing the sensitivity of NMR measurements by maximizing magnetic field strength at the center, thereby improving signal detection.
Implementation Method 1
The resonant circuit includes a sample coil and transmission lines whose total length is set to specific values to maximize magnetic field strength at the center, allowing for uniform and intense magnetic field production by adjusting the transmission line lengths to satisfy equations such as Ln = λ + (n-1)λ/2, ensuring standing waves resonate at the desired RF frequency
Implementation Method 2
The NMR probe produces a magnetic field at the resonant frequency, the strength of the field being maximized in the center of the sample coil
Data Source
AI summary
An NMR (nuclear magnetic resonance) probe is offered which produces a magnetic field strength adapted for producing an NMR signal within a sample coil. The probe has a resonant circuit including a sample coil, a first transmission line, and a second transmission line. The resonant circuit is designed taking account of the transmission line length Ls of the coil, the transmission line length La of the first line, and the transmission line length Lb of the second line. The coil is placed in a position where the magnetic field strength is maximized. Where the electrical characteristics of the resonant circuit are varied by connection of the coil and transmission lines, the transmission line lengths are corrected according to the variations.