Array Antenna Driving for 3D NMR Logging
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Solution Overview
Problem
Current nuclear magnetic resonance logging tools are limited to radial and axial depth dimension signal detection, lacking the capability for circumferential multi-directional signal detection, and cannot perform three-dimensional scanning due to the absence of a driving device for such functionality.
Innovation Solution
An array antenna driving method and device for a three-dimensional scanning nuclear magnetic resonance imager, which includes a bus interface module, pulse timing processing module, multi-channel high-power pulse transmitting module, and antenna switching interface module, enabling the generation and superposition of high voltage radio frequency pulses to drive an array antenna for nuclear magnetic resonance signal transmission, allowing for radial, axial, and circumferential stratum detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a columnar magnet with single antenna is used, then the structure is simple and easy to manufacture, but the signal detection capability is limited to radial and axial dimensions only, lacking circumferential multi-directional detection
Solution Approach 1:
The single antenna is divided into multiple antenna elements arranged in an array configuration around the magnet. Each antenna element can be independently controlled to detect signals from different circumferential directions, enabling three-dimensional signal detection capability while maintaining a relatively simple overall structure.
Solution Approach 2:
The antenna system transitions from detecting only radial and axial dimensions to adding circumferential multi-directional detection capability by arranging antenna elements in a three-dimensional array configuration around the magnet, enabling detection in all three spatial dimensions.
2Measurement precision
If a single antenna is used for 360° excitation, then the device complexity is low, but the measured signal is only an average signal without circumferential resolution
Solution Approach 1:
The single antenna is segmented into multiple independently controllable antenna elements. By controlling different antenna elements to transmit signals in different directions and receiving signals from different circumferential positions, the system achieves circumferential resolution while maintaining manageable system complexity through modular design.
Solution Approach 2:
The antenna driving system employs dynamic control of multiple antenna elements through time-varying excitation patterns. By sequentially activating different antenna elements and using signal processing to distinguish signals from different directions, the system achieves high measurement precision without requiring all antennas to operate simultaneously, thereby controlling device complexity.
3Adaptability or versatility
If multiple antenna elements are added for three-dimensional scanning, then the signal detection capability in radial, axial and circumferential dimensions is improved, but the driving device complexity increases
Solution Approach 1:
The driving device is designed with multi-functional capability to control multiple antenna elements for different detection purposes. The same driving system can perform radial, axial, and circumferential scanning by configuring different antenna elements, eliminating the need for separate driving devices for each dimension and thereby controlling overall device complexity.
Solution Approach 2:
A signal processing system acts as an intermediary between the multiple antenna elements and the detection system. This intermediary processes signals from different antenna elements, distinguishes signals from different directions, and presents the processed information to the user, thereby managing the complexity of controlling multiple antennas while maintaining three-dimensional scanning capability.
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 convenient and quick feeding of high voltage radio frequency pulses to the array antenna, allowing for single or multi-azimuth stratum information detection, thereby improving circumferential resolution and enabling three-dimensional stratum detection.
Implementation Method 1
a multi-channel high-power pulse transmitting module including a plurality of pulse transmitting channels respectively connected to the pulse timing processing module, each of the pulse transmitting channels being configured to process an externally inputted high voltage signal according to the pulse transmission timing signal and outputs a high voltage radio frequency pulse
Implementation Method 2
configured to select a pulse transmitting channel and an antenna to be operated in the nuclear magnetic resonance pulse array antenna according to the antenna switching control signal, and superpose the high voltage radio frequency pulse outputted by each of the selected pulse transmitting channels to drive the antenna to be operated to transmit a nuclear magnetic pulse signal
Implementation Method 3
a nuclear magnetic resonance pulse array antenna, and configured to select a pulse transmitting channel and an antenna to be operated in the nuclear magnetic resonance pulse array antenna
Data Source
AI summary
Provided is an array antenna driving method and device for a three-dimensional scanning nuclear magnetic resonance imager, wherein each antenna to be operated is driven to transmit a nuclear magnetic pulse signal by receiving a control command sent by a control system; parsing the control command to generate a pulse transmission timing signal and an antenna switching control signal; processing an externally inputted high voltage signal according to the pulse transmission timing signal to output high voltage radio frequency pulses of a plurality of channels; and selecting a high voltage radio frequency pulse of at least one channel and the antenna to be operated in the nuclear magnetic resonance pulse array antenna according to the antenna switching control signal, and superposing the selected high voltage radio frequency pulse. The device of the present invention can improve multi-layer slice information detection of signals in circumferentially different azimuth zones.