PIN Diode Switching Speed for MRI Applications

This paper presents the results of an investigation of PIN diode switching speed using a variety of PIN diode types that include high speed receive switching devices as well as high power transmitting PIN diodes. A short introduction on the PIN diode simulation model will be provided and then simulations of a common MRI transmit/receive switch will be used to compare the different device switching speeds. The results show that thick I-region diodes are shown to exhibit extremely low resistance values at high currents, providing low insertion loss at the high RF powers in transmitting, active detune and block switching applications as well as robust blocking/detuning functions, but at a slower switching rate compared with thinner devices.