HE920 Hardware User Guide
1vv0301014 Rev.9 – 2014-01-23
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
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Page 43 of 84
Furthermore if the device is developed for the US and/or Canada market, it must comply with
the FCC and/or IC approval requirements:
This device is to be used only for mobile and fixed application. In order to re-use the Telit
FCC/IC approvals the antenna(s) used for this transmitter must be installed to provide a
separation distance of at least 20 cm from all persons and must not be co-located or operating
in conjunction with any other antenna or transmitter. If antenna is installed with a separation
distance of less than 20 cm from all persons or is co-located or operating in conjunction with
any other antenna or transmitter then additional FCC/IC testing may be required. End-Users
must be provided with transmitter operation conditions for satisfying RF exposure compliance.
OEM integrators must ensure that the end user has no manual instructions to remove or install
the HE920 module. Antennas used for this OEM module must not exceed 6.79dBi gain for
850MHz bands, 3.01dBi gain for 1900MHz bands and 2.7dBi for 1700MHz bands for mobile
and fixed operating configurations.
6.2.
GSM/WCDMA Antenna – PCB line Guidelines
Make sure that the transmission line’s characteristic impedance is 50ohm.
Keep line on the PCB as short as possible since the antenna line loss shall be less than
around 0.3dB.
Line geometry should have uniform characteristics, constant cross section, avoid
meanders and abrupt curves.
Any kind of suitable geometry/structure can be used for implementing the printed
transmission line afferent the antenna.
If a Ground plane is required in line geometry, that plane has to be continuous and
sufficiently extended so the geometry can be as similar as possible to the related
canonical model.
Keep, if possible, at least one layer of the PCB used only for the Ground plane; If
possible, use this layer as reference Ground plane for the transmission line.
It is wise to surround (on both sides) of the PCB transmission line with Ground. Avoid
having other signal tracks facing directly the antenna line track.
Avoid crossing any un-shielded transmission line footprint with other tracks on
different layers.
The Ground surrounding the antenna line on PCB has to be strictly connected to the
main Ground plane by means of via holes (once per 2mm at least) placed close to the
ground edges facing line track.
Place EM noisy devices as far as possible from HE920 antenna line.
Keep the antenna line far away from the HE920 power supply lines.
If EM noisy devices are present on the PCB hosting the HE920, such as fast switching
ICs, take care of shielding them with a metal frame cover.
If EM noisy devices are not present around the line use of geometries like Micro strip
or Grounded Coplanar Waveguide are preferred since they typically ensure less
attenuation when compared to a Strip line having same length.
