Rainbow Electronics GE863-PY - Manual (Page 32)

GE863 Hardware User Guide
1vv0300783 Rev.0 - 10/06/08
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 32 of 80
5.4.3 LNA and Front End Design Considerations
LNA gain should be between 12 dB and 26 dB (assumes a patch antenna).
– This assumes the patch used has >3 dBic of gain
Linear antenna implementation should consider a minimum of ~14.5 dB of LNA gain.
Excessive LNA gain (>27 dB) can introduce jamming spurs, degrade 3IP, and saturate the
receiver.
The supply voltage most accept the range between 3.4 to 4.2 V DC
In highly integrated environments rich with potential interference, SiRF suggests design
implementations with PRE filters.
The module’s GPS input is already provided of a SAW filter.
As suggested on the Product Description the external active antenna for a Telit GE863-GPS device
shall fulfil the following requirements:
ANTENNA REQUIREMENTS
Frequency range 1575.42 MHz (GPS L1)
Bandwidth +- 1.023 MHz
Gain 1.5 dBi < Gain < 4.5 dBi
Impedance 50 ohm
Amplification Typical 25dB (max 27dB)
Supply voltage Must accept from 3 to 5 V DC
Current
consumption Typical 20 mA (40 mA max)
When using the Telit GE863-GPS, since there's no antenna connector on the module, the antenna
must be connected to the GE863-GPS through the PCB with the antenna pad.
In the case that the antenna is not directly developed on the same PCB, hence directly connected at
the antenna pad of the GE863-GPS, then a PCB line is needed in order to connect with it or with its
connector.