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 42 of 84
6.
Antenna(s)
The antenna connection and board layout design are the most important parts in the full
product design and they strongly reflect on the product’s overall performances. Read carefully
and follow the requirements and the guidelines for a proper design.
6.1.
GSM/WCDMA Antenna Requirements
The antenna for a Telit HE920 device must fulfill the following requirements:
When using the Telit HE920, since there’s no antenna connector on the module, the antenna
must be connected to the HE920 antenna pad (AD1) by means of a transmission line
implemented in the PCB.
In the case that the antenna is not directly connected at the antenna pad of the HE920, then a
PCB line is required in order to connect with it or with its connector.
This transmission line shall fulfill the following requirements:
Antenna Line on PCB Requirements
Characteristic Impedance
50Ohm
Max Attenuation
0.3dB
Coupling with other signals shall be avoided
Cold End (Ground Plane) of antenna shall be equipotential to the HE920 ground pads
GSM / WCDMA Antenna Requirements
Frequency
range
Depending by frequency band(s) provided by the network operator, the
customer must use the most suitable antenna for that/those band(s)
Bandwidth
HE920-EU
HE920-NA
GSM850 : 70 MHz
GSM900 : 80 MHz
GSM1800(DCS) : 170 MHz
GSM1900(PCS) : 140 MHz
WCDMA band I(2100) : 250 MHz
WCDMA band V(850) : 70 MHz
WCDMA band VIII(900) : 80 MHz
GSM850 : 70 MHz
GSM900 : 80 MHz
GSM1800(DCS) : 170 MHz
GSM1900(PCS) : 140 MHz
WCDMA band II(1900) : 140 MHz
WCDMA band IV(AWS) : 445 MHz
WCDMA band V(850) : 70 MHz
Impedance
50 Ohm
Input power
> 33dBm(2 W) peak power in GSM
> 24dBm Average power in WCDMA
VSWR
absolute max
<= 5:1(limit to avoid permanent damage)
VSWR
recommended
<= 2:1(limit to fulfill all regulatory requirements)
