76 dBi.
These antennas also have moderately small bandwidths of operation. Generally, designing
an antenna that is tunable in manufacture is highly desirable (Rao et al., 2005). This implies
TABLE 4.4
An Outline for Evaluating Antenna Design Requirements
Operational
frequency band
Operational frequency of the tag will depend on the country or countries in which the
tag is deployed. Table 4.1 outlines a list of such frequency bands in the UHF spectrum
Tag dimensions Tag size requirements will depend on the application. For instance, the tag may need to
be printed on a label for sticking on a cardboard box, embedded in plastic casing or
placed within the con?¬?ned space of a bottle cap
Label cost constraints Keeping the cost of a tag to a minimum will limit the choice of RFID ICs that can be used,
as well as the type of material that can be used for constructing the antenna. Generally,
tag antennas are constructed using copper, aluminum, or silver ink, while the material
used for the substrate may be anything from paper, polyester to FR4 dielectrics
Read range
requirements
Consider the read range required by the particular application. Generally less ef?¬?cient,
smaller antennas may be used for smaller read range requirements. The read range is
also affected by the electromagnetic compatibility regulations which control the EIRP
or ERP of the reader antenna.
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