C.1 Introduction - Texas Instruments 2000 Series Reference Manual

C.1 Introduction
This appendix gives an example of how you could construct an antenna to work with the Micro-reader. It
also provides information about calculating the Q factor and adapting the inductance range.
The antenna properties should be:
Q factor less than 20
Inductance between 46 µH and 48 µH
Recommended maximum size 200 mm × 200 mm
C.2 Antenna Construction
Item List:
Method:
• Wind 15 turns of item 1 with a diameter of 75 mm.
• Leave about 50 mm free at the ends, cross the wires (at the ± 50 mm point) and secure them together
using the tape (item 2).
• Twist the spriband (item 4) onto the coil that you have just made, leaving the start and finish ends free.
• Strip the insulating braid back at the end of the antenna lead (item 5). Wrap the start and finish ends at
least three times around the bared ends and solder the joints (the polarity is not important).
• Tightly bind the soldered joints to the spriband using the cloth tape (item 3).
This method should result in a 47 µH antenna with a quality factor of approximately 17 to 18.
SCBU027 – May 2000
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Item Description
1 Enamelled solid copper wire, 0.2 mm
2 Tape, 10 mm wide
3 Block cloth tape, 12 mm wide
4 Spiroband, 3 mm diameter
5 Screened antenna lead
Appendix C
SCBU027 – May 2000
Antenna Design
Quantity
2.1 g
20 mm
0.12 m
0.24 m
1 m
Antenna Design 45