Antennas; Types Of Antenna And Properties; Antenna Parameters - Siemens SIMATIC RF600 System Manual

6.4.4

Antennas

6.4.4.1

Types of antenna and properties

Basically all types of directional antennas can be considered as third-party antennas for
integration into the SIMATIC RF600 system. Directional antennas have a preferred direction
in which more energy is radiated than in other directions.
6.4.4.2

Antenna parameters

Overview
The properties of an antenna are determined by a large number of parameters. You must be
aware of these properties in order to make the correct selection for your appropriate UHF
antenna. The most important parameters are described below. These important parameters
are described in detail in the following sections. The following parameters describe both the
send and receive functions of the antenna (reciprocity). The antenna is a passive antenna. A
two-way relationship exists.
● Radiated power
● Antenna gain
● Impedance
● Return loss / VSWR
● Power rating
● Polarization
● Front-to-back ratio
● Beam width
Radiated power
In order to comply with national directives with regard to the radiated power (which differ
depending on the location or country of use), the RF660R reader together with the antenna
cable(s) and antenna(s) must be exactly parameterized or configured.
This means that the product of the transmitted power P
G must always have the correct ratio with regard to the radiated power "EIRP" depending on
the location of use or the permissible frequency band.
Calculation of the radiated power is briefly described below.
Calculation of the radiated power
The radiated power is the total power radiated by the antenna in the room. The isotropic radiator
serves as the physical computing model which uniformly radiates the power into the room
(spherically).
SIMATIC RF600
System Manual, 06/2010, J31069-D0171-U001-A10-7618
Draft Version 02.06.2010
6.4 Guidelines for selecting RFID UHF antennas
of the reader and the antenna gain
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Antennas
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