Abstract: A magnetic resonance imaging (MRI) apparatus that includes a multi-resonance transmit/receive (T/R) switch, one switch design having a top side and a bottom side of a microstripline based hybrid coupler, a first pin diode, a second pin diode, four vertical transmission lines and six horizontal transmission lines arranged in a bended manner on the microstripline. The top side is associated with a first port and a second port, and electrically connected to the first pin diode and the second pin diode. The bottom side is associated with a third port and a fourth port, and electrically connected with the first pin diode and the second pin diode. The switch receives radio frequency (RF) pulses of different frequencies transmitted to and received from an MRI RF coil where the different frequencies are received concurrently and without tuning by the multi-resonance T/R switch from the MRI RF coil.

Abstract: A resonant wearable antenna system includes a ground plane and an antenna structure positioned over the ground plane. The ground plane includes a first cloth substrate and an array of metamaterial (MTM) unit cells positioned on the substrate. At least one MTM unit cell includes four four-leaf-clover units arranged in a four-leaf-clover pattern and connected to a center unit. Each four-leaf-clover unit includes four leaf units arranged in a four-leaf-clover pattern and connected to a subcenter unit. The antenna structure includes a second cloth substrate and a conductive pattern positioned over the second cloth substrate. The antenna structure is configured to have a first resonant frequency below 1 GHz and a second resonant frequency higher than the first resonant frequency. The array of MTM unit cells is configured to reflect incident waves, from the antenna structure at the first resonant frequency and the second resonant frequency, in-phase.

Abstract: A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.

Abstract: A resonant wearable antenna system includes a ground plane and an antenna structure positioned over the ground plane. The ground plane includes a first cloth substrate and an array of metamaterial (MTM) unit cells positioned on the substrate. At least one MTM unit cell includes four four-leaf-clover units arranged in a four-leaf-clover pattern and connected to a center unit. Each four-leaf-clover unit includes four leaf units arranged in a four-leaf-clover pattern and connected to a subcenter unit. The antenna structure includes a second cloth substrate and a conductive pattern positioned over the second cloth substrate. The antenna structure is configured to have a first resonant frequency below 1 GHz and a second resonant frequency higher than the first resonant frequency. The array of MTM unit cells is configured to reflect incident waves, from the antenna structure at the first resonant frequency and the second resonant frequency, in-phase.

Abstract: A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.

Abstract: A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.

Abstract: A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.

Abstract: A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.

Abstract: A magnetic resonance imaging apparatus includes a T/R switch. The T/R switch includes a double sided microstripline based hybrid couplers with a top side and a bottom side each including two concentric microstripline based hybrid couplers. Each of the two concentric microstripline based hybrid couplers includes an inner microstripline based hybrid coupler and an outer microstripline based hybrid coupler. The inner microstripline based hybrid coupler forms an inner loop of the two concentric microstripline based hybrid couplers and the outer microstripline based hybrid coupler forms an outer loop. In a transmission mode, the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side of the dual-tuned T/R switch are activated. In a receiving mode the inner microstripline based hybrid coupler and the outer microstripline based hybrid coupler at the top side and at the bottom side of the dual-tuned T/R switch are activated.