LISA-C2 series and FW75-C200 - System Integration Manual
UBX-13000620 - R21
Early Production Information
Design-In
Page 59 of 103
2.4
Antenna guidelines
Antenna characteristics are essential for good functionality of the module. Antenna radiating performance has
direct impact on the reliability of connections 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
nominal characteristic impedance
Frequency Range
Depends on the Mobile Network used.
LISA-C200 & FW75-C200:
- Cell Band BC0: 824..894 MHz
- PCS Band BC1:1850..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 30: General recommendation for CDMA antenna
To preserve the original u-blox FCC ID, antenna gain shall remain below 3 dBi.
CDMA antennas are typically available as:
•
Linear monopole: typical for fixed applications. 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). These 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 by minimizing 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 RF 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.
