Ublox NORA-W36 Series, System Integration Manual

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NORA-W36 series - System integration manual
UBX-22021120 - R01 Design-in Page 16 of 48
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Table 3 summarizes the requirements for the antenna RF interface:
Item Requirements Remarks
Impedance
50  nominal characteristic
impedance
The impedance of the antenna RF connection must match
the 50
 impedance of the ANT pin.
Frequency Range 2400 – 2500 MHz
5150 – 5850 MHz
Wi-Fi and Bluetooth
Wi-Fi
Return Loss
S
11
< -10 dB (VSWR < 2:1)
recommended
S
11
< -6 dB (VSWR < 3:1) acceptable
The Return loss ( S) as the VSWR refers to the amount of
reflected power, measuring how well the primary antenna
RF connection matches the 50
 characteristic impedance
of the ANT pin.
The impedance of the antenna termination must match as
much as possible the 50
 nominal impedance of the ANT
pin over the operating frequency range, thus maximizing
the amount of the power transferred to the antenna.
Efficiency > -1.5 dB ( > 70% ) recommended
> -3.0 dB ( > 50% ) acceptable The radiation efficiency is the ratio of the radiated power to
the power delivered to the antenna input; the efficiency is a
measure of how well an antenna receives or transmits.
Maximum Gain Refer to Data sheet
The maximum antenna gain must not exceed the value
specified in type approval documentation to comply with
the radiation exposure limits specified by regulatory
agencies.
Table 3: Summary of antenna interface (ANT) requirements for NORA-W361
Observe the following recommendations while selecting external or internal antennas:
• Select antennas that provide optimal return loss, based on the Voltage Standing Wave Ratio
(VSWR) figure, over all the operating frequencies.
• Select antennas that provide an optimal efficiency figure over all the operating frequencies.
• Select antennas that provide an appropriate gain figure (that is, combined antenna directivity and
efficiency figure) so that the electromagnetic field radiation intensity does not exceed the
regulatory limits specified in some countries (by FCC in the United States for example).
3.2.2.1 RF connector design
If an external antenna is required, designers should consider using a proper RF connector. It is the
responsibility of the designer to verify the compatibility between plugs and receptacles used in the
design.
Table 4 suggests several RF connectors that designers can use to connect RF coaxial cables - based
on the declaration of the respective manufacturers. Hirose U.FL-R-SMT RF receptacles (or similar
parts) require suitable mated RF plugs from the same connector series. Due to wide usage of this
connector, several manufacturers offer compatible equivalents.
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 4: U.FL compatible connectors