Triangular Microstrip NMR Probe Head for Spatial Resolution
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Solution Overview
Problem
Existing probe heads for nuclear magnetic resonance spectroscopy are not suitable for spatially resolved measurements on samples with limited mass and volume, particularly for planar samples like microfluidic chips, as they do not allow for precise spatial distribution and concentration analysis of organic molecules.
Innovation Solution
A microstrip line probe head with a triangular cross-sectional reduction in the printed circuit board, enabling the generation of radio frequency field gradients that provide spatially resolved nuclear magnetic resonance spectroscopy without mechanical forces or eddy currents, and a second microstrip structure with a rectangular cutout for homogeneous pulse generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate gradient coils are used for spatially resolved MR spectroscopy, then spatial resolution is achieved, but mechanical forces are exerted on the sample and costly gradient amplifiers are required
Solution Approach 1:
The patent replaces the mechanical gradient coil system with an electrical solution using a microstrip conductor with triangular constriction. The varying width of the microstrip conductor creates a linear gradient in current density, which generates the required magnetic field gradient without mechanical components. This substitution eliminates mechanical forces on the sample while achieving spatial resolution.
2Measurement precision
If separate gradient coils are used for spatially resolved MR spectroscopy, then spatial resolution is achieved, but costly gradient amplifiers are required
Solution Approach 1:
The patent combines the gradient coil function with the RF excitation coil function into a single integrated structure. The microstrip conductor with triangular constriction serves dual purposes: generating the RF field for excitation and creating the magnetic field gradient for spatial resolution. This merging eliminates the need for separate gradient coils and their associated expensive amplifiers.
3Quantity of substance
If solenoid coils are used for small sample quantities, then sensitivity for small samples is improved, but planar samples like microfluidic chips cannot be used
Solution Approach 1:
The patent transitions from a three-dimensional solenoid coil geometry to a two-dimensional planar microstrip conductor structure. This dimensional change allows the probe to accommodate planar samples such as microfluidic chips while maintaining sensitivity for small sample quantities. The planar geometry matches the sample geometry, enabling direct contact and efficient coupling.
4Measurement precision
If external magnetic field gradients are used, then spatial resolution is achieved, but eddy currents are generated
Solution Approach 1:
The patent replaces external magnetic field gradient generation with an electrical current density gradient approach. By varying the current density linearly across the microstrip conductor width, the desired magnetic field gradient is produced directly during RF excitation, avoiding the need for separate gradient switching that would induce eddy currents in external coils.
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 high-resolution, non-invasive spatially resolved measurements of organic molecule distributions and concentrations in small samples, maintaining the homogeneity of the external magnetic field and avoiding the need for expensive gradient amplifiers, suitable for use in high-resolution spectrometers and microfluidic chip samples.
Implementation Method 1
the cross-sectional reduction is a triangular constriction that leads to a linear variation of the current density and thus of the corresponding radio frequency field as a function of location
Implementation Method 2
the microstrip conductor structure has a microstrip conductor with a cross-sectional reduction for generating and detecting a radio frequency field
Data Source
Figure 1
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Figure 5~7
AI summary
The invention relates to a sample head for nuclear magnetic resonance spectroscopy having a circuit board made of a dielectric material which supports a microconductor structure, said microconductor structure comprising a microconductor having a cross-sectional reduction for generating and detecting a radio frequency field, wherein the sample head is to be further developed such that the sample head is suitable for enabling spatially resolved nuclear magnetic resonance spectroscopy for samples of limited mass and of limited volume. This is achieved in that the cross-sectional reduction of the microconductor structure is designed as a triangular constriction (7), in such a way that the width of the constriction decreases over the length of the constriction.