Hybrid MRI Receiving Coil With Modified Dipole Gain Boost
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Solution Overview
Problem
The gain of receiving coils in MRI systems is limited due to the restricted size, as increasing the number of loop coils reduces the diameter of each coil, leading to a weaker magnetic field strength.
Innovation Solution
Incorporating a modified dipole antenna with a parasitic element inside the loop coil, utilizing electromagnetic induction and a split ring configuration to enhance impedance matching without lumped-parameter elements, thereby increasing the antenna gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of loop coils is increased to improve gain, then the gain of the receiving coil is improved, but the diameter of each loop coil becomes smaller leading to weaker magnetic field strength
Solution Approach 1:
The patent combines a dipole antenna structure with a loop coil structure to form a hybrid receiving coil element. The dipole antenna (including main dipole and parasitic element) is integrated within the loop coil structure, allowing the element to function as both a magnetic field sensor (loop coil) and an electric field sensor (dipole antenna). This merging enables improved gain without reducing the loop coil diameter.
Solution Approach 2:
The receiving coil element uses a composite structure combining conductive materials configured as both loop coils and dipole antennas. The main dipole and parasitic element are formed using conductive materials that also form the loop coil structure, creating a composite electromagnetic sensing element that leverages both magnetic and electric field reception capabilities.
2Quantity of substance
If the diameter of loop coil is reduced to increase the number of coils, then the number of loop coils is increased, but the magnetic field strength generated by each coil becomes weaker
Solution Approach 1:
The patent merges the functions of multiple loop coils with dipole antenna elements into hybrid receiving elements. Each hybrid element combines the magnetic field sensing capability of loop coils with the electric field sensing capability of dipole antennas, providing enhanced signal reception strength without requiring an increased number of smaller loop coils.
Solution Approach 2:
The patent transitions from relying solely on magnetic field detection (one dimension) to detecting both magnetic and electric fields (additional dimension). By incorporating dipole antenna elements that detect electric fields in addition to loop coils detecting magnetic fields, the system achieves improved signal strength through multi-dimensional electromagnetic detection.
3Power
If a parasitic element is added to the dipole antenna, then the directivity and gain are improved, but the device complexity increases
Solution Approach 1:
The parasitic element is nested within the structure of the main dipole antenna. The parasitic element (including split ring components) is positioned inside or along the structure of the main dipole, allowing both elements to function together as an integrated antenna system without requiring separate mounting structures or complex assembly procedures.
Solution Approach 2:
The parasitic element serves multiple functions: it acts as a reflector to improve directivity, provides additional signal reception capability, and helps define the radiation pattern of the antenna. By integrating this single element to perform multiple functions, the patent achieves improved gain and directivity without proportionally increasing device complexity.
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 modified dipole configuration enhances the receiving coil's gain by improving directivity and reducing losses, allowing for more efficient MR signal reception.
Implementation Method 1
The RF signal, which arises due to the precession of magnetic moments inside an object subjected to MR investigation, induces an electro motive force (EMF) in the main dipole
Implementation Method 2
Incorporating a modified dipole antenna with a parasitic element inside the loop coil, utilizing electromagnetic induction and a split ring configuration to enhance impedance matching without lumped-parameter elements
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
In one embodiment, a receiving coil (20) includes a plurality of coil elements (200), wherein: at least one of the coil elements (200) includes a loop coil (210) and a modified dipole (300) disposed inside the loop coil (210); and the modified dipole (300) includes a main dipole (310) configured to receive a radio-frequency "RF" signal and output a reception signal and a parasitic element (320, 330) that includes a split ring (321, 331) having a gap (322, 332) in part of a ring shape.