Specifications
LEON-G100/G200 - System Integration Manual
GSM.G1-HW-09002-C Preliminary Design-In
Page 60 of 75
2.2.3 Placement
Optimize placement for minimum length of RF line and closer path from DC source for VCC.
2.3 Module thermal resistance
The Case-to-Ambient thermal resistance (R
C-A
) of the module, with the LEON-G100/G200 mounted on a 130 x
110 x 1.6 mm FR4 PCB with a high coverage of copper (e.g. the EVK-G25H evaluation kit) in still air conditions is
equal to 14°C/W.
With this Case-to-Ambient thermal resistance, the increase of the module temperature is:
Around 12°C when the module transmits at the maximum power level during a GSM call in the GSM/EGSM
bands;
Around 17°C when the module transmits at the maximum power level during a GPRS data transfer (2 Tx + 3
Rx slots) in the GSM/EGSM bands;
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 have direct impact on the reliability of connection over the Air Interface. A bad termination of ANT can
result in poor performance of the module.
The following parameters should be checked:
Item
Recommendations
Impedance
50 Ω
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 dBic
Table 9: 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