ATAB8402 Atmel, ATAB8402 Datasheet - Page 3

• Manufacturer Part Number: ATAB8402
• Description: BOARD DEMO 433MHZ RF TRANSMITTER
• Manufacturer: Atmel
• Type: Transmitterr

Specifications of ATAB8402

• Frequency: 433MHz
• Wireless Frequency: 315 MHz
• Modulation: ASK, FSK
• For Use With/related Products: ATA8402
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

9115A–INDCO–01/08
L
The equivalent circuit for the loop antenna is shown in
Figure 2-1.
An estimation of the loop inductance is necessary to match the loop antenna. This value can be
determined using a formula for inductance of a polygon of general shape (Equation 6). This for-
mula provides a result with 5% accuracy.
Notes:
The Q factor of the loop antenna is given by
To optimize the performance of the loop antenna the following rules must be considered:
Figure 2-2.
Q
• The area enclosed by the loop has to be designed as large as possible and the ground area
• The field density increases towards the loop edges. Therefore, enough space must be
• The trace width of the loop antenna should not exceed 1.5 mm to avoid a large antenna Q
=
loop
within the loop must be small.
provided near to the loop edges.
factor.
2
=
10
Ground
1. L is the loop perimeter
2. A is the loop area
3. W is the trace width of the loop antenna
-------------- -
R
L
-7
loss
loop
l
Equivalent Circuit of a Loop Antenna
Layout Design of the Loop Antenna
ln
8A
------ -
lw
Ideal
Equation 7
Equation 6
Antenna
R
Loop
Rad
ATA8401/ATA8402/ATA8403
R
loss
Loop
Figure
Ground
2-1.
Suboptimal
Antenna
Loop
3