User Manual

ZE51/61-2.4 RF Module User Guide
1VV0300868 Rev.4 – 31/03/2011
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 43 of 50
VII.3. Antenna types
The following are the antenna examples that may be suitable for ZE51/61-2.4/SMD-WA applications. We
distinguish two types of antenna:
 External antenna (antenna is mounted outside of the device)
 Embeddable antenna (antenna is integrated inside the device)
VII.4. External antenna
External antenna is recommended when the range performance is primordial. For example, for base stations and
access points, where a better antenna gain may be required.
¼ Wave Monopole antenna:
The ¼ Wave antenna is 3 cm long @ 2.4 Ghz. Shorter compensated antennas could be used as long as they are
adapted to 2.4 GHz frequency.
Best range may be achieved if the ¼ Wave antenna is placed perpendicular in the middle of a solid ground plane
measuring at least 5 cm radius. In this case, the antenna should be connected to the module via some 50 ohm
characteristic impedance coaxial cable.
WARNING
The metallic plane must be ideally under the antenna (balanced radiation). Never
short-circuit the hot and cold pins!
The installation directives are the following:
 Solder the coaxial cable on the hot and ground pad antenna (of the ZE51/61-2.4 module.)
 Fix the antenna on a metallic plane or on a metallic box with the metallic screw provided with the antenna.
 If the ZE51/61-2.4 module is integrated in a plastic box, use a metal tape (copper) glued on the plastic
side under the antenna.
Coaxial hot and ground soldered
on the ZE51 RF output
Ground plane
connected to coaxial
ground
¼ Wave Antenna,
connected to hot point.