ATAB8402 Atmel, ATAB8402 Datasheet - Page 2

• 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

2
ATA8401/ATA8402/ATA8403
For radiation, a loop antenna needs a strong current flowing through it in order to generate a
magnetic field as the loop antenna is a magnetic antenna. The radiation resistance of the
antenna is a primary determiner of the antenna’s transmitted power.
Notes:
A second important parameter of the antenna’s transmitted power is the loss of the loop
antenna. This can be derived from the skin depth theory under the assumption that the trace
width is much greater than trace’s thickness, which is greater than the skin depth. The loss resis-
tance for a copper trace can be calculated with the following equation:
Notes:
In order to estimate the transmit power using the loop antenna, it is necessary to determine the
efficiency of the antenna. This is given by:
Notes:
The radiated power can be calculated, as follows:
Note:
The relationship between the effective radiated power (ERP) and the IC’s output power
(Pout,IC) driving the antenna is:
R
R
P
ERP
Rad
Rad
loss_loop
=
------------------------------------------------------------------------ -
R
=
=
Rad
31.2
1. A is the loop area in square meters
2.
1. L is the total perimeter of the antenna in meters referring to the trace’s centre
2. W is the trace width in meters
1. R
2. R
3. R
I
I
loop
+
loop
P
R
------ -
2w
is the current flow through the loop antenna
out,IC
loss_loop
l
Rad
loss_loop
loss_cap
is the wavelength in meter
2
10
R
Rad
is the radiation resistance of the antenna
R
3
2.59
Rad
A
------
is the loss of the capacitors for the matching
+
is the loss resistance of the loop’s trace
4
2
R
Equation 5
loss_cap
10
-7
f
Equation 1
Equation 4
Equation 2
Equation 3
9115A–INDCO–01/08