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 45 of 50
VII.5. Embeddable antennas
In this section you will find antennas designed to be directly attached to ZE51/61-2.4/SMD-WA module, inside the
product casing. These antennas are only used in application where security, cosmetics, size or environmental
issues make an external antenna impractical. This type of antenna is used when the integration factor becomes
primordial (for mobile and handheld devices) to the range performances.
The basic recommendations are:
 The radio module must not be placed in a metallic casing or close to metallic devices.
 The internal antenna must be far from noisy electronic.
Ceramic antenna:
Ceramic antenna is a SMD component to be mounted directly on the PCB. It is designed so that it resonates and
be 50 Ohms at the desired frequency. But we recommended to place an impedance-matching circuit (See
paragraph VII.2).
The place under and around the ceramic antenna must be free of any track or ground plane. (refer to the antenna
constructor requirements). It usually has a hemispherical radiation pattern has described below.
Miniaturized antenna:
This type of antenna features a through-hole feedline to directly attach it to the PCB. This antenna acts like a ¼
wave antenna so that a minimum ground plane is required.