Multi‐ and dual‐tuned microstripline‐based transmit/receive switch for 7‐Tesla magnetic resonance imaging

Abstract

This article introduces two new designs of transmit/receive switches for 7‐Tesla magnetic resonance imaging. Both designs based on a microstripline coupler technology. In the first design, a different single frequency signals can be handled to/from a radio frequency coil using smart tuning network. In the second design, a dual‐tuned 1H/23Na transmit/receive switch is designed to handle a dual resonant signal to a dual resonant 1H/23Na coil, simultaneously and without tuning. In transmit and receive, the first design achieved good matching (‐20 dB), and low insertion loss (0.78 dB) for the 1H, 19F, 31P, 13C, and 23Na magnetic resonance signals with high isolation (61 dB). Similarly, the dual‐tuned 1H/23Na switch achieved good matching (<−11.5 dB) and low insertion loss (1.0 dB) with high isolation (67 dB), whereas for 1H/31P switch, good matching has been achieved (<−12 dB) and low insertion loss (0.96 dB) with high isolation (62 dB). The first proposed switch enables the use of the same switch with different coils resonating at Larmor frequencies of different atomic nuclei. The second switch can handle a dual resonant signal to a single dual resonant coil. The first design is promising in reducing the costs by using the same switch with different coils. The second design is promising in the integration with multichannel dual resonant coil.

Two-section branch-line hybrid couplers based broadband transmit/receive switch

“…The introduced switch achieves a compact design with minimum dimensions and without increasing the temperature 20 degree Celsius beyond the ambient temperature. Dual tuned MSL-based T/R switches have also been introduced to work properly with dual resonance RF coils to interrogate different Xnuclei [25]. Our proposed and introduced microstripline-based switches can handle the RF pulses, with very low insertion loss, as well as good return loss and isolation, to/from single and dual tuned RF coils.…”

Dual tuned 1H/31P quadrature microstripline-based transmit/receive switch for 7 Tesla magnetic resonance imaging

“…In [25], a 1H/13C single-coupler switch has been presented to be integrated with 1H/13C RF coil. Recently, T/R switch for 7 T MRI has been presented to deliver a dual resonant signal to a dual resonant coil [26].…”