US 12,467,993 B2 · 1H transmit/receive switch for 3T and 7T magnetic resonance imaging

Abstract

A transmit/receive switch for magnetic resonance imaging (MRI) of a 1H atomic nucleus at 3 T (tesla) and 7 T magnetic field strengths includes a first and second dielectric substrate and a first and a second microstripline hybrid coupler formed on the first and second dielectric substrates respectively. A first port and a second port are connected to a first junction and a second junction respectively of the first microstripline hybrid coupler, a third port and a fourth port are connected to a third junction and a fourth junction of the second microstripline hybrid coupler respectively. Each port is connected by a matching network embodied by a microstripline wire to a pair of parallel resonant circuits. The transmit/receive switch is configured to operate at a fundamental frequency of about 127.8 MHz at 3 T and at a third harmonic frequency of about 298 MHz at 7 T.

A hybrid coupler for magnetic resonance imaging (MRI) of a 1H atomic nucleus at 3 T (tesla) and 7 T magnetic field strengths, comprising:

a dielectric substrate having a first edge opposite a second edge and a third edge opposite a fourth edge, wherein a first central axis of the dielectric substrate is configured to bisect the first edge and the second edge and to extend from the first edge to the second edge and wherein a second central axis of the dielectric substrate is configured to bisect the third edge and the fourth edge and to extend from the third edge to the fourth edge;
a multi-bended microstripline configured to have a first arm, a second arm, a third arm and a fourth arm;
a first port connected by a microstripline wire to a junction between the first arm and the fourth arm;
a first pair of parallel resonant circuits connected to the junction between the first arm and the fourth arm;
a second port connected by a microstripline wire to a junction between the third arm and the fourth arm;
a second pair of parallel resonant circuits connected to the junction between the third arm and the fourth arm;
a third port connected by a microstripline wire to a junction between the third arm and the second arm;
a third pair of parallel resonant circuits connected to the junction between the third arm and the second arm;
a fourth port connected by a microstripline wire to a junction between the first arm and the second arm;
a fourth pair of parallel resonant circuits connected to the junction between the first arm and the second arm,
wherein the first arm includes a first angled leg, an S-shaped loop connected to the straight leg, an inverted S-shaped loop connected to the S-shaped loop, and a second angled leg, wherein the S-shaped loop and the inverted S-shaped loop have mirror image symmetry about the second central axis,
wherein the second arm includes a first angled leg, a first straight leg parallel to the second edge, a second straight leg perpendicular to the first straight leg, a first loop which extends towards the third edge, a second loop which extends towards the second central axis, a third loop which extends towards the fourth edge, a third straight leg parallel to the second straight leg, a fourth straight leg parallel to the second edge and which extends towards the fourth edge, and a second angled leg,
wherein the third arm is located opposite the first arm and is a mirror image of the first arm about the first central axis,
wherein the fourth arm is located opposite the second arm and is a mirror image of the second arm about the second central axis, and
wherein the first arm and the third arm each have a microstripline width Wa, the second arm and the fourth arm each have a microstripline width Wb, wherein Wb is about seven times Wa;
wherein the multi-bended microstripline is configured to receive RF electrical signals at the first port and transmit RF electrical signals at a resonance frequency of about 127.8 MHz and at a third harmonic frequency of about 298 MHz from each of the second port and at the fourth port, wherein the RF electrical signals transmitted from the fourth port are orthogonal to the RF electrical signals transmitted from the second port,
wherein the third port is isolated.

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1H transmit/receive switch for 3T and 7T magnetic resonance imaging

Life of this patent

1H transmit/receive switch for 3T and 7T magnetic resonance imaging

Life of this patent

Abstract

Claims20