Chipless RFID Reader Architecture
Answers to RF Cafe Quiz #53

RF Engineering Quizzes - RF CafeAll RF Cafe quizzes would make perfect fodder in employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job.

Click here for the complete list of RF Cafe Quizzes.
Note: Some material based on books have quoted passages.

Return to RF Cafe Quiz #53

Chipless RFID Reader Architecture - RF CafeThis quiz is based on the information presented in Chipless RFID Reader Architecture, by Nemai Chandra Karmakar, Randika V. Koswatta, Prasanna Kalansuriya, and Rubayet E-Azim. Graciously provided by Artech House.

Note: Some of these books are available as prizes in the monthly RF Cafe Giveaway.

1.  What is a major advantage of chipless RFID over existing RFID?

b)  Lower cost

Chipless RFID must be produced in the sub-cent range in order to provide low-cost, item-level tagging that is competitive with UPC scans.  (see page 2)

2.  What is a name given to fully printable, passive microwave and millimeter-wave chipless RFID tags?

b)  Radar arrays
RFID works on a radar type principle where an interrogation signal is broadcast and then the receiver listens for an echo with detectable data.  (see page 15)

3.  What is the assigned frequency (or band) on (within) which RFID systems must operate?

d)  There is no specific assigned frequency / band
See paper by Enigmatics and Impinj  (FCC website)

4.  What type(s) of frequency domain based RFID tags are currently in use?

d)  All the above
Many types of schemes are use, but the chemical tag is the most interesting (to me) in that it uses many different compounds that resonate at discrete frequencies to reply with unique identification codes.  (see page 20)

5.  What is the common name given to the device that performs the interrogation of an RFID system?

a)  A reader
'Reader' is the common name, and 'interrogator' is the technical nomenclature.  (see page 43)

6.  What is / are the current limitation(s) of chipless RFID readers?

d)  All the above
Because the entire onus of signal quality and processing is placed on the reader. In addition to the three issues there are also anti-collision, error correction, and tag orientation limitations.  (see page 60)

7.  What is a rectenna?

c)  A rectifying antenna that converts a microwave signal into DC power
(see page 284)

Circular Log Periodic RFID Antenna - RF Cafe

8.  What type of antenna is shown to the right?

c)  Circular log periodic
(see page 177)

9.  What is the most basic antenna that can yield omnidirectional radiation patterns over a UWB (ultra wide bandwidth) band?

a)  Disk-loaded monopole
A disk-loaded monopole is the most basic antenna that can yield omnidirectional radiation patterns and a uniform return loss over the UWB band.  (see page 200)

10.  How can smart antenna technology mitigate the interference problem of RFID reading?

b)  With electronic beam steering
A smart antenna can solve the interference problem by electronically controlling the main beam emitted from the reader's antenna toward the desired tags and nulls toward the interfering signal.  (see page 150)

Posted  September 25, 2013