Impedance tuner, magnetic resonance system, transmission apparatus, and transmission method

Patent metadata

Field	Value
Publication number	US-12478280-B2
Application number	US-202318194862-A
Country	US
Kind code	B2
Filing date	Apr 3, 2023
Priority date	Apr 26, 2022
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

An impedance tuner in a magnetic resonance system include at least one of an amplitude tuning circuit and a phase tuning circuit. The amplitude tuning circuit includes M serially-connected amplitude tuners. Each amplitude tuner includes at least one microwave transmission line and a first switch circuit connected in parallel, wherein the first switch circuit controls the at least one microwave transmission line to be in an on state or an off state, respectively, and the value of M is a positive integer greater than or equal to 1. The phase tuning circuit includes a phase tuner, and the phase tuner includes P second microwave transmission lines and a second switch circuit, wherein the second switch circuit controls the P second microwave transmission lines to be in an on state or an off state, respectively, and the value of P is a positive integer greater than or equal to 2.

First claim

The invention claimed is:

1 . An impedance tuner, characterized in that the impedance tuner comprises at least one of: an amplitude tuning circuit and a phase tuning circuit;
the amplitude tuning circuit comprises M serially-connected amplitude tuners; each amplitude tuner comprises at least one first microwave transmission line and a first switch circuit connected in parallel, the first switch circuit being configured to control the at least one first microwave transmission line to be in an on state or an off state, respectively, and the value of M is a positive integer greater than or equal to 1; the phase tuning circuit comprises a phase tuner, the phase tuner comprising P second microwave transmission lines and a second switch circuit, the second switch circuit being configured to control the P second microwave transmission lines to be in an on state or an off state, respectively, and the value of P is a positive integer greater than or equal to 2; wherein the impedance tuner further comprises: a controller configured to receive a measurement of a standing wave ratio; when the standing wave ratio is greater than a threshold, the controller is configured to sequentially adjust each first microwave transmission line to be in an on state or an off state via the first switch circuit until the measured standing wave ratio is less than or equal to the threshold.

2 . The impedance tuner according to claim 1 , wherein the length of the first microwave transmission line is one-quarter wavelength.

3 . The impedance tuner according to claim 1 , wherein the different amplitude tuners have the same or different number of the first microwave transmission lines; and
the different amplitude tuners have the same or different characteristic impedance of the first microwave transmission lines.

4 . The impedance tuner according to claim 3 , wherein the at least one first microwave transmission line has the same or different characteristic impedance.

5 . The impedance tuner according to claim 3 , wherein, when M is greater than 1, the characteristic impedance of at least one first microwave transmission line in the amplitude tuner is correlated with the characteristic impedance of at least one first microwave transmission line in an amplitude tuner adjacent to said amplitude tuner.

6 . The impedance tuner according to claim 1 , wherein the P second microwave transmission lines have the same characteristic impedance.

7 . The impedance tuner according to claim 1 , wherein the P second microwave transmission lines have the same or different phase or length.

8 . The impedance tuner according to claim 1 , wherein the P second microwave transmission lines comprise at least one second microwave transmission line having a length of one-half wavelength.

9 . The impedance tuner according to claim 8 , wherein except for the second microwave transmission line having a length of one-half wavelength, the adjacent second microwave transmission lines in the remaining second microwave transmission lines have the same phase difference or length difference.

10 . The impedance tuner according to claim 1 , wherein when the impedance tuner comprises the amplitude tuning circuit and the phase tuning circuit, the phase tuner is serially connected to one amplitude tuner in the amplitude tuning circuit.

11 . A transmission apparatus of a magnetic resonance system, characterized in that the apparatus comprises:
a signal output unit, configured to generate and output a pulse signal; a radio-frequency power amplifier, configured to amplify the pulse signal; at least one impedance tuner for transferring the signal amplified by the radio-frequency power amplifier to a transmit coil of the magnetic resonance system in the same space as the radio-frequency power amplifier; wherein the at least one impedance tuner comprises at least one of: an amplitude tuning circuit and a phase tuning circuit; wherein the amplitude tuning circuit comprises M serially-connected amplitude tuners; each amplitude tuner comprises at least one first microwave transmission line and a first switch circuit connected in parallel, the first switch circuit being configured to control the at least one first microwave transmission line to be in an on state or an off state, respectively, and the value of M is a positive integer greater than or equal to 1; wherein the phase tuning circuit comprises a phase tuner, the phase tuner comprising P second microwave transmission lines and a second switch circuit, the second switch circuit being configured to control the P second microwave transmission lines to be in an on state or an off state, respectively, and the value of P is a positive integer greater than or equal to 2; wherein the apparatus further comprises: a processor, for measuring a standing wave ratio;
when the standing wave ratio is greater than a threshold, the processor controls the first switch circuit to sequentially adjust each first microwave transmission line to be in an on state or an off state until the measured standing wave ratio is less than or equal to the threshold; or
when the standing wave ratio is greater than a threshold, the processor controls the second switch circuit to sequentially adjust each second microwave transmission line to be in an on state or an off state until the measured standing wave ratio is less than or equal to the threshold; or
when the standing wave ratio is greater than a threshold, the processor controls the first switch circuit and the second switch circuit to sequentially adjust each first microwave transmission line and each second microwave transmission line to be in an on state or an off state until the measured standing wave ratio is less than or equal to the threshold.

12 . The apparatus according to claim 11 , wherein the apparatus further comprises:
a controller, for adjusting the equivalent impedance of the impedance tuner to correspond to the load impedance of the transmit coil, so as to achieve impedance matching.

13 . The apparatus according to claim 11 , wherein the controller controls the first switch circuit to adjust each first microwave transmission line to be in an on state or an off state, so as to achieve impedance matching; or, the controller controls the second switch circuit to adjust each second microwave transmission line to be in an on state or an off state, so as to achieve impedance matching; or, the controller controls the first switch circuit and the second switch circuit to adjust each first microwave transmission line and each second microwave transmission line to be in an on state or an off state, so as to achieve impedance matching.

14 . The apparatus according to claim 11 , wherein the controller controls at least one of the first switch circuit and the second switch circuit by using a high voltage signal and a current source signal of the transmission apparatus.

15 . The apparatus according to claim 11 , wherein the number of the impedance tuners is 2 when the transmit coil comprises independent I and Q channels.

16 . A magnetic resonance system, wherein the system comprises:
a transmit coil; and the transmission apparatus according to claim 11 .

17 . A transmission method of a magnetic resonance system, wherein the method comprises:
generating and outputting a pulse signal by a signal output unit; amplifying the pulse signal by a radio-frequency power amplifier; transferring, by the impedance tuner, the signal amplified by the radio-frequency power amplifier to a transmit coil of the magnetic resonance system; wherein the i

Assignees

• Ge Prec Healthcare Llc

Inventors

• Ning Jianye
• Xie Xin
• Liu Yu
• Xiao Chunlai
• Tong Sheng
• Yang Dongliang
• Wang Kai

Classifications

• A61B5/053

  Measuring electrical impedance or conductance of a portion of the body · CPC title

• G01R33/3664

  Switching for purposes other than coil coupling or decoupling, e.g. switching between a phased array mode and a quadrature mode, switching between surface coil modes of different geometrical shapes, switching from a whole body reception coil to a local reception coil or switching for automatic coil selection in moving table MR or for changing the field-of-view (G01R33/3671 takes precedence) · CPC title

• G01R33/3614

  RF power amplifiers · CPC title

• G01R33/3607

  RF waveform generators, e.g. frequency generators, amplitude-, frequency- or phase modulators or shifters, pulse programmers, digital to analog converters for the RF signal, means for filtering or attenuating of the RF signal · CPC title

• A61B5/055 Primary

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title