Miniaturized NMR Transmit/Receive Switch Design
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Solution Overview
Problem
Conventional NMR spectrometers are large and expensive, making them impractical for many applications that require continuous, real-time chemical composition monitoring, as they necessitate centralized analysis and are too costly for industrial and quality control uses.
Innovation Solution
A miniaturized NMR spectrometer with a novel RF switching system using four-diode switches and a resonant impedance matching network, allowing for efficient power matching and noise isolation, enabling smaller coils and reduced power requirements, thus achieving spectral resolution below 1 ppm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional NMR spectrometers are used, then spectral resolution better than 1.0 ppm is achieved, but device size and cost become prohibitively large
Solution Approach 1:
The patent segments the NMR system into a miniaturized probe assembly that can be integrated into smaller devices. The probe contains separate transmit and receive coils, preamplifiers, and switching circuits that are miniaturized versions of conventional components, enabling high-resolution NMR in a compact form factor suitable for industrial applications
Solution Approach 2:
The patent changes the operating parameters by using a dual-coil system with independent transmit and receive coils, implementing separate preamplifiers for each coil, and using a switching circuit to alternate between transmit and receive modes. This parameter change enables miniaturization while maintaining spectral resolution better than 1.0 ppm
2Measurement precision
If conventional NMR spectrometers are used, then spectral resolution better than 1.0 ppm is achieved, but purchase and maintenance cost become excessive
Solution Approach 1:
The patent designs a miniaturized NMR probe that can be manufactured at lower cost using standard electronic components and miniaturized coils. The probe is designed as a self-contained unit that can be easily replaced or upgraded, reducing the overall system cost and making it suitable for industrial and quality control applications where conventional spectrometers are too expensive
3Volume of stationary object
If miniaturized NMR device is designed, then device size and cost are reduced, but power requirements and coil size become constraints
Solution Approach 1:
The patent segments the power management by implementing separate preamplifiers for the transmit and receive coils, with each preamplifier having its own power supply circuitry. This segmentation allows optimized power delivery to each coil while keeping the overall device compact and reducing total power requirements compared to conventional systems
4Device complexity
If transmit and receive functions share common components, then device complexity is reduced, but noise isolation and power matching become problematic
Solution Approach 1:
The patent segments the transmit and receive functions into separate coils, preamplifiers, and switching circuits. The transmit coil and preamplifier are physically separated from the receive coil and preamplifier, with a switching circuit that isolates the receive path from transmit signals. This segmentation provides effective noise isolation while maintaining manageable device complexity
Solution Approach 2:
The patent introduces a switching circuit as an intermediary between the transmit and receive paths. This switch isolates the receive preamplifier from transmit signals during transmission, preventing noise and interference from reaching the sensitive receive electronics, while allowing both functions to share common structural elements of the probe assembly
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 miniaturized NMR spectrometer provides cost-effective, real-time chemical analysis capabilities, suitable for industrial and quality control applications, with spectral resolution of 0.123 ppm, enabling multiple installations for simultaneous data collection and analysis.
Implementation Method 1
A resonant impedance matching network transforms power from a transmitter output stage to a coil at an NMR frequency
Implementation Method 2
A first one of the four-diode switches isolates noise from a transmitter output stage from a receiver input stage during a transmit mode
Implementation Method 3
A wire coil and electronic circuits are provided to both apply radio-frequency (RF) pulses to the sample (transmit) and to detect RF signals from the sample (receive)
Implementation Method 4
Nuclear magnetic resonance (NMR) techniques are widely used for analyzing properties of fluids and solids
Data Source
AI summary
A single-pole, double-throw, transmit/receive switch for switching a NMR coil between a transmit mode and a receive mode comprises two diode bridge switches on opposites sides of a node the is common with the two diode bridges and the NMR coil. One of the two diode bridges is positioned between the coil and a preamplifier for signals received from the coil, and the other diode bridge is positioned between the coil and a RF signal transmitter for connecting and disconnecting transmitted signals to and from the coil. The NMR coil is connected to the switches through a resonant impedance matching network.