RF Antenna Frequency Converter for MR Signal Integrity
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Solution Overview
Problem
RF antennas in MR systems are sensitive to common mode coupling due to capacitive, inductive, and electromagnetic couplings, which can lead to noise interference in signal transmission.
Innovation Solution
Incorporating a frequency converter on an insulating substrate with an RF antenna to shift the primary frequency band away from the measured frequency, using high-pass filtering and encoding techniques to minimize common mode coupling, and including demodulator and decoder circuits to recover the original signal efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signal transmission is performed from the RF antenna using conventional methods, then the signal can be transmitted, but common mode coupling causes noise interference and reduces signal integrity
Solution Approach 1:
The patent changes the frequency parameter by converting the primary band of frequencies (containing the measured frequency) to a converted band of frequencies that is substantially different from the measured frequency. This frequency transformation allows common mode coupling to be removed using simple filtering techniques, thereby improving signal integrity while eliminating the harmful common mode interference
Solution Approach 2:
The patent introduces a frequency converter as an intermediary device between the resonant pickup circuit and the output. This frequency converter acts as a mediator that transforms the signal to a different frequency band, enabling the separation of the desired signal from common mode noise through filtering, thus resolving the contradiction between signal transmission and noise rejection
2Reliability
If multiple filter stages are used to remove common mode coupling, then noise interference can be reduced, but device complexity increases
Solution Approach 1:
By changing the frequency parameter through conversion to a substantially different frequency band, the patent enables the use of simple filtering techniques instead of multiple complex filter stages. The frequency transformation shifts the signal away from the common mode coupling frequency, allowing a single simple filter to achieve noise rejection that would otherwise require multiple filter stages
Solution Approach 2:
The patent extracts the frequency conversion function into a separate frequency converter component. This extraction allows the common mode coupling to be removed through simple filtering of the converted frequency band, reducing the complexity of the overall filtering system while maintaining effective noise rejection
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
Significantly reduces common mode coupling, enhancing signal integrity by minimizing unwanted signal interference and reducing the need for multiple filter stages, thereby improving the efficiency of signal filtering and transmission.
Implementation Method 1
a resonant pickup circuit arranged to pick up a magnetic resonance (MR) signal at a measured frequency
Implementation Method 2
the frequency converter comprises electronic circuitry to convert the frequency components in the primary band of frequencies to a converted band of frequencies substantially different from the measured frequency
Implementation Method 3
If the upconverted frequency band is sufficiently removed from the measured frequency, common mode coupling in the RF range can be removed using simple high-pass (HP) filtering techniques
Data Source
AI summary
A radio frequency antenna comprising a resonant pickup circuit (102) arranged to pick up a magnetic resonance signal, an analog-to-digital converter (105) arranged to convert the magnetic resonance signal to digital data, and a frequency converter arranged to convert a primary band of frequencies of the digital data. By upshifting the frequency of the transmitted bit-stream, it is possible to RF-trap the transmission channel (109) by simple high-pass filtering techniques. In case the transmitted bit pattern has frequency components that approach the resonance frequency, an encoding technique like Manchester encoding can be used to eliminate unwanted signals.