Performance of PIN diode RF switches within HF RFID reader designs

Multiplexing and controlling radio frequency (RF) signals through the use of PIN diodes is a well-established design technique used by electronic engineers. The usual trade-offs between electromechanical relays, transistors and PIN diodes include: switching speeds, acoustic noise, component longevity, signal integrity and cost. Not surprisingly, given the low cost of PIN diodes, together with the pressure on build costs, you will frequently find them incorporated in RFID reader circuitry. A designer needs to be cognoscente of some of the performance issues that are associated with their inclusion. Through simulation, this paper highlights some of the nuances of RFID readers incorporating PIN diodes and highlights the pitfalls to avoid in order to design a reader that is EMC (Electromagnetic Compatibility) compliant.