LEON-G100 / LEON-G200 - System Integration Manual
GSM.G1-HW-09002-G3
Preliminary
Design-In
Page 93 of 125
Case-to-Ambient thermal resistance value will be different than the one provided if the module is
mounted on a PCB with different size and characteristics.
2.4
Antenna guidelines
Antenna characteristics are essential for good functionality of the module. The radiating performance of
antennas has direct impact on the reliability of connection over the Air Interface. Bad termination of
ANT
can
result in poor performance of the module.
The following parameters should be checked:
Item
Recommendations
Impedance
50
Ω
nominal characteristic impedance
Frequency Range
Depends on the Mobile Network used.
GSM900: 880..960 MHz
GSM1800: 1710..1880 MHz
GSM850: 824..894 MHz
GSM1900: 1850..1990 MHz
Input Power
>2 W peak
V.S.W.R
<2:1 recommended, <3:1 acceptable
Return Loss
S
11
<-10 dB recommended, S
11
<-6 dB acceptable
Gain
<3 dBi
Table 31: General recommendation for GSM antenna
GSM antennas are typically available as:
Linear monopole: typical for fixed application. The antenna extends mostly as a linear element with a
dimension comparable to lambda/4 of the lowest frequency of the operating band. Magnetic base may be
available. Cable or direct RF connectors are common options. The integration normally requires the
fulfillment of some minimum guidelines suggested by antenna manufacturer
Patch-like antenna: better suited for integration in compact designs (e.g. mobile phone). They are mostly
custom designs where the exact definition of the PCB and product mechanical design is fundamental for
tuning of antenna characteristics
For integration observe these recommendations:
Ensure 50
Ω
antenna termination, minimize the V.S.W.R. or return loss, as this will optimize the electrical
performance of the module. See section 2.4.1
Select antenna with best radiating performance. See section 2.4.2
If a cable is used to connect the antenna radiating element to application board, select a short cable with
minimum insertion loss. The higher the additional insertion loss due to low quality or long cable, the lower
the connectivity
Follow the recommendations of the antenna manufacturer for correct installation and deployment
Do not include antenna within closed metal case
Do not place antenna in close vicinity to end user since the emitted radiation in human tissue is limited by
S.A.R. regulatory requirements
Do not use directivity antenna since the electromagnetic field radiation intensity is limited in some countries
Take care of interaction between co-located RF systems since the GSM transmitted power may interact or
disturb the performance of companion systems
Place antenna far from sensitive analog systems or employ countermeasures to reduce electromagnetic
compatibility issues that may arise
