u-blox ANTARIS 4 User Manual

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your position is our focus
Generaldesignrecommendations:
• Thelengthofthemicrostriplineshouldbekeptasshortaspossible.Lengthsover2.5cm(1inch)shouldbe
avoidedonstandardPCBmaterialand additionalshielding.without
• Distance between micro strip line and ground area on the top layer should at least be
 as large as the
dielectricthickness.
• RoutingtheRFconnectionclosetodigitalsectionsofthedesignshouldbeavoided.
• Toreducesignalreflections,sharp anglesintheroutingofthemicrostriplineshouldbeavoided.Chamfers
or fillets are preferred for rectangular routing; 45-degree routing is preferred
over Manhattan style
90-degreerouting.
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Antenna
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Antenna
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Antenna
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30
PCB
30
PCB PCB
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Wrong better best
• RoutingoftheRF-connectionunderneaththe receivershouldbeavoided.Thedistanceofthemicrostripline
tothegroundplaneonthebottomsideofthereceiverisverysmall(some100µm)andhashugetolerances
(upto100%).Therefore,theimpedanceofthis
partofthetracecannotbecontrolled.
• Useasmanyviasaspossibletoconnectthegroundplanes.
• Inordertoavoidreliabilityhazards,theareaonthePCBunderthereceivershouldbeentirelycoveredwith
soldermask.Viasshouldnotbeopen.
3.6.5 Antenna Micro Strip
Therearemanywaystodesignwave-guidesonprintedcircuitboards.Commontoallisthatcalculationofthe
electrical parameters is not straightforward. Freeware tools like AppCAD from Agilent or TXLine from Applied
Wave Research, Inc. are of great help. They can be downloaded from
www.agilent.com and
www.mwoffice.com.
Themicrostripisthemostcommonconfigurationforprintedcircuitboards.Thebasicconfigurationisshownin
Figure 45 and Figure 46.As arule ofthumb, fora FR-4materialthewidthoftheconductorisroughly double
thethicknessofthedielectrictoachieve50Ohmslineimpedance.
 to consider the distance
and theadjacent GND
eonthesamelayer
 UsetheCoplanarWaveguidemodelforthecalculation
ofthemicrostrip.
For
the correct calculation of the micro strip impedance, one does not only need
betweenthe topand thefirstinnerlayerbutalso thedistance betweenthe microstrip
plan
Note:

GPSModules-SystemIntegrationManual(SIM)(incl.ReferenceDesign) Design-In
GPS.G4-MS4-05007-A1
  Page 56

u-blox ANTARIS 4 Specifications

General

Brand	u-blox
Model	ANTARIS 4
Category	GPS
Language	English