4.10 Exercises

RFID configurations:

• 4.1. How many antennas are used simultaneously for transmit and receive functions in a monostatic RFID reader?

  ________

• 4.2. A bistatic antenna provides 45 dB of isolation from transmit to receive, and is used with a 1/2-W transmitter. How much transmit power leaks into the receiver?

  ________dBm

Radio architectures:

• 4.3. A superheterodyne receiver (which might be employed for a listen-before-talk application under European regulations) uses a local oscillator frequency of 800 MHz to receive a signal at 867 MHz. What is the intermediate frequency (IF)? What is the image frequency?

  IF: ______ MHz image: _______ MHz

• 4.4. A direct conversion RFID receiver is intended to successfully receive a tag signal as small as -65 dBm, with a resulting output voltage swing of 0.5 V to drive a comparator with a 300- ? input resistance. What is the overall gain of the receiver? What voltage would be produced by a -10 dBm input signal?

  Gain: ______ dB interferer output: ______ volts

Radio components:

• 4.5. An amplifier has a gain of 14 dB. An input signal of -10 dBm causes the amplifier to suffer 1 dB of gain compression. What is PldB?

  PldB:________dBm

• 4.6. An RFID receiver operating at 906.5 MHz is also illuminated by two other nearby readers operating at 909 and 912.5 MHz. What spurious frequencies might be produced in the receiver by third-order distortion? Are they likely to interfere with the tag signal at 906.5 MHz?

  low...