Methods, devices and systems for protecting RFID reader front ends
An RFID protection scheme includes monitoring an output signal of a least one receiver mixer of the reader, and, based at least in part on said monitoring, when said output signal exceeds a predetermined threshold, performing one or more of the following: removing an RF signal from a transmitter power amplifier (PA); removing a bias from the PA; causing a protection switch to divert transmitter power away from an antenna circuit; and signaling a processor to reduce transmitter power.
1 . A method of protecting circuitry of an radio frequency identification reader, the method comprising:
monitoring an output signal of a least one receiver mixer of the reader, and, based at least in part on said monitoring, when said output signal exceeds a predetermined threshold, performing one or more of the following:
(a) reducing or removing an RF signal from a transmitter power amplifier (PA);
(b) reducing or removing a bias from the PA;
(c) causing a protection switch to divert transmitter power away from an antenna circuit; and
(d) signaling a processor to indicate that said output signal has exceeded said predetermined threshold.
2 . A method as in claim 1 wherein said step (a) comprises:
removing or reducing the RF drive signal using at least one of a silicon, PIN (Positive-Intrinsic-Negative), or gallium arsenide (GaAs) switch or attenuator.
3 . An Radio Frequency Identification (RFID) reader comprising:
(A) first circuitry providing a first RF signal to at least one antenna connected thereto to cause said antenna to emit an RF signal, said first circuitry including a transmitter power amplifier;
(B) second circuitry for reading a second RF signal for an antenna connected thereto; and
(C) a protection mechanism connected to an output of said second circuitry and constructed and adapted to prevent said second signal from damaging said first or said second circuitry.
4 . An RFID reader as in claim 3 wherein the protection mechanism is constructed and adapted to monitor the second RF signal, and, in response to said monitoring, when said second RF signal exceeds a predetermined threshold, to reduce the first RF signal from the transmitter power amplifier.
5 . An RFID reader as in claim 3 wherein the protection mechanism is constructed and adapted to monitor the second RF signal, and, in response to said monitoring, when said second RF signal exceeds a predetermined threshold, to remove the first RF signal from the transmitter power amplifier.
6 . An RFID reader as in claim 3 wherein the protection mechanism is constructed and adapted to monitor the second RF signal, and, in response to said monitoring, when said second RF signal exceeds a predetermined threshold, to reduce a bias from the transmitter power amplifier.
7 . An RFID reader as in claim 3 wherein the protection mechanism is constructed and adapted to monitor the second RF signal, and, in response to said monitoring, when said second RF signal exceeds a predetermined threshold, to remove a bias from the transmitter power amplifier.
8 . An RFID reader as in claim 3 wherein said first circuitry further comprises a protector switch, and wherein the protection mechanism is constructed and adapted to monitor the second RF signal, and, in response to said monitoring, when said second RF signal exceeds a predetermined threshold, to causing said protection switch to divert at least some transmitter power away from an antenna circuit.
9 . An RFID reader as in claim 3 wherein said first circuitry further comprises a protector switch, and wherein the protection mechanism is constructed and adapted to monitor the second RF signal, and, in response to said monitoring, when said second RF signal exceeds a predetermined threshold, to signal a processor to reduce transmitter power of said first RF signal.