UK
RFID-UHF-Antennas
11
5 Reader output power
The maximum output power for the reader is defined by the ETSI standard EN 302
208-1 V1�2�1 (dated April 2008)� It is defined by the antenna gain, the half power
beam width and the cable attenuation on the reader - antenna connection�
For antennas with a half power beam width of up to 70° a power of
P
ERP,max
= 2 W ERP (Effective Radiated Power) is allowed. For other half power
beam widths the power is limited to P
ERP,max
= 0,5 W ERP.
The ERP is converted in accordance with EN 302 208-1 into output power PC at
the reader as follows:
P
C,max
= P
ERP,max
- G
IC
+ 5,15 + C
L
For the antenna ANT820 the following maximum output power is then obtained:
P
C,max
= 27 dBm - 4 dBic + 5,15 + 0 dB = 28,15 dBm = 0,653 W
Where:
P
C,max
: refers to the maximum output power of the reader in dBm,
P
ERP,max
: refers to the maximum effective radiated power of the antenna in dBm,
G
IC
: refers to the circular antenna gain in dBic,
C
L
: the cable loss in dB (here assumed to be 0 dB)