Ublox TOBY-L2 series, System Integration Manual

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TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R28 Design-in Page 88 of 164
Guidelines for MPCI-L2 series ANT1 / ANT2 receptacles RF connection design
The Hirose U.FL-R-SMT RF receptacles implemented on the MPCI-L2 series modules for ANT1 / ANT2
ports require a suitable mated RF plug from the same connector series. Due to its wide usage in the
industry, several manufacturers offer compatible equivalents.
Table 25 lists some RF connector plugs that fit MPCI-L2 series modules RF connector receptacles,
based on the declaration of the respective manufacturers. Only the Hirose has been qualified for the
MPCI-L2 series modules; contact other producers to verify compatibility.
Manufacturer Series Remarks
Hirose U.FL® Ultra Small Surface Mount Coaxial Connector Recommended
I-PEX MHF® Micro Coaxial Connector
Tyco UMCC® Ultra-Miniature Coax Connector
Amphenol RF AMC® Amphenol Micro Coaxial
Lighthorse Technologies, Inc IPX ultra micro-miniature RF connector
Table 25: MPCI-L2 series U.FL compatible plug connector
Typically the RF plug is available as a cable assembly: several kinds are available and the user should
select the cable assembly best suited to the application. The key characteristics are:
 RF plug type: select U.FL or equivalent
 Nominal impedance: 50 
 Cable thickness: typically from 0.8 mm to 1.37 mm. Select thicker cables to minimize insertion loss

Cable length: standard length is typically 100 mm or 200 mm, custom lengths may be available on
request. Select shorter cables to minimize insertion loss
 RF connector on the other side of the cable: for example another U.FL (for board-to-board
connection) or SMA (for panel mounting)
For applications requiring an internal integrated SMT antenna, it is suggested to use a U-FL-to-U.FL
cable to provide RF path from the MPCI-L2 series module to PCB strip line or micro strip connected to
antenna pads as shown in
Figure 45 . Take care that the PCB-to-RF-cable transition, strip line and
antenna pads must be designed so that the characteristic impedance is as close as possible to 50  :
see the following subsections for specific guidelines regarding RF transmission line design and RF
termination design.
If an external antenna is required, consider that the connector is typically rated for a limited number
of insertion cycles. In addition, the RF coaxial cable may be relatively fragile compared to other types
of cables. To increase application ruggedness, connect U.FL to a more robust connector (e.g. SMA or
MMCX) fixed on panel or on flange as shown in
Figure 45 .
MPCI-L2 series
Baseboard
Stripline/Microstrip
Internal
Antenna
Baseboard
Application
Chassis
Connector to
External Antenna
MPCI-L2 series
Screw / Fastener
for Mini PCIe
Screw / Fastener for Mini PCIe
Figure 45: Example of RF connections, U.FL-to-U.FL cable for internal antenna and U.FL-to-SMA for external antenna