The transmit/receive (T/R) switch is an important device in magnetic resonance imaging scanners whenever T/R radio frequency coils are intended to be used. It is placed between transmit amplifiers and T/R radio frequency coils. The T/R switch adds loss to the radio frequency (RF) transmit chain, reducing the delivered power to the coil and increasing the noise figure of the receive chain. Therefore, T/R switches should be designed for as low insertion loss as possible. In addition, they need to handle high power in transmit. In this article, three T/R switches for 7-Tesla magnetic resonance imaging scanners are designed using Eagle, and validated by simulation (HFSS & ANSYS) and measurement. Low reflection coefficients (< −20 dB), low insertion loss (≃0.3 dB), and high isolation (>40 dB) were demonstrated for the designed couplers. The fabricated microstripline-based switches were more robust than a design utilizing commercial couplers in terms of heat dissipation, high power capabilities, and lower insertion loss.

中文翻译：

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用于 7-Tesla 磁共振成像的基于对称和非对称微带线的发射/接收开关

无论何时打算使用 T/R 射频线圈，发射/接收 (T/R) 开关都是磁共振成像扫描仪中的重要设备。它位于发射放大器和 T/R 射频线圈之间。T/R 开关增加了射频 (RF) 发射链的损耗，降低了传送到线圈的功率并增加了接收链的噪声系数。因此，T/R 开关的设计应尽可能降低插入损耗。此外，它们需要在传输中处理高功率。在本文中，使用 Eagle 设计了三个用于 7-Tesla 磁共振成像扫描仪的 T/R 开关，并通过仿真 (HFSS & ANSYS) 和测量进行了验证。设计的耦合器证明了低反射系数 (< -20 dB)、低插入损耗 (≃0.3 dB) 和高隔离度 (>40 dB)。