Antenna Trace Details

FCC ID: XPYVERAP173

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FCCID_3683999

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VERA-P173 Antenna Reference Design

  Topic :                 VERA-P173 antenna reference design
                          UBX-17061097                                                                                              Confidential – For Internal Use
  Author :                smay, ddie
  Date :                  2017-11-09
  To :                    Application engineer
We reserve all rights in this document and in the information contained therein. Reproduction, use or disclosure to third parties without express authority is strictly forbidden.   2017 © u-blox AG




1 Scope
This document defines the essential specifications necessary to implement the VERA-P173 antenna reference
designs. The information contained herein and its references should be sufficient to guide a skilled person in an
attempt to implement the design on a host carrier. It will provide the designer with PCB layout details and expected
performance specifications.
The document supports a connector-based designs for the use of external antennas (one for each antenna pin of
the module)

2 FCC/IC ID reference
  Model                                                                    FCC ID                                                                IC ID
  VERA-P173                                                                XPYVERAP173                                                           TBD
Table 1: FCC and IC ID


3 General description and requirements
VERA-P173 antenna reference design module provides two RF interfaces for connecting the external antennas.
Antenna ports ANT1 and ANT2 have a nominal characteristic impedance of 50  and must be connected to the
related antenna through a 50  transmission line to allow proper impedance matching along the RF path; a bad
termination of the pin may result in poor performance or even damage to the RF section of the module.
For optimal antenna performance in multi-radio mode, the isolation between the antennas must be maximized;
the designer must follow the requirements specified in Table 2 and Table 3 to ensure good performance.




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 Item                Requirements                           Remarks

 Impedance           50  nominal characteristic            The impedance of the antenna RF connection must match the
                     impedance                              50  impedance of the ANTx pin.
 Frequency Range     5850 - 5925 MHz                       For 802.11p.
 Return Loss         S11 < -13 dB (VSWR < 1.5:1) Abs. Max. The Return loss or the S11, 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 ANTx pin.
                                                           The impedance of the antenna termination must match as much as
                                                           possible the 50  nominal impedance of the ANTx pin over the operating
                                                           frequency range thus, maximizing the amount of the power transferred to
                                                           the antenna.
 Efficiency          > -1.5 dB ( > 70% ) recommended       The radiation efficiency is the ratio of the radiated power to the power
                     > -3.0 dB ( > 50% ) acceptable        delivered to the antenna input. The efficiency is a measure of how well an
                                                           antenna receives or transmits.

Table 2: Summary of antenna interface requirements

 Item                    Requirements                                  Remarks

 Isolation               |S21| > 50 dB recommended                     The antenna to antenna isolation is the loss between the primary
 (in-band)               |S21| > 43 dB minimum                         and the secondary antenna; high isolation results from low
                                                                       coupled antennas.
 Isolation               |S21| > 35 dB recommended                     Out-of-band isolation is evaluated in the band of the aggressor
 (out-of-band)           |S21| > 30 dB acceptable                      to ensure that the transmitting signal from the other radio is
                                                                       sufficiently attenuated by the receiving antenna to avoid
                                                                       saturation and intermodulation effects at the receiver’s port.

Table 3: Summary of antenna isolation requirements


4 Reference design of RF path
The reference design of the 50 Ω path to connect the modules antenna pins with a SMA connector is displayed in
Figure 1 and the dimensions concerning the board stack-up (Table 4) are specified in Table 5. An SMA connector
is used to mount the antenna from Table 6.
 PCB Layer                                   Material                                      Thickness
 Solder mask top                             General LPI solder mask                       20 µm
 Top                                         Copper Foil                                   35 µm
 Dielectric                                  Pre-preg                                      600 µm
 L2                                          Copper Foil                                   35 µm
 Dielectric                                  Core                                          240 µm
 L3                                          Copper Foil                                   35 µm
 Dielectric                                  Pre-preg                                      600 µm
 Bottom                                      Copper Foil                                   35 µm
 Solder mask bottom                          Generic LPI Soldermask                        20 µm
Table 4: Stack-up of VERA-P1-EVK with standard FR4 substrate (εr = 4.6)




Figure 1: Coplanar waveguide with ground dimension specification




DocNumber: UBX-17061097                                                                                                       Page 2/3


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 Item                           Value
 S                              400 µm
 W                              900 µm
 T                              35 µm
 H                              600 µm
 Spacing between ANT1           16 mm
 and ANT2 waveguides
Table 5: Coplanar waveguide with ground specification


5 Antenna
The module has been approved for use with any dipole antenna with less or equal to 6 dBi peak gain. An example
of an approved antenna is listed in Table 6.
 Model name                     Manufacturer and description                          Gain [dBi] (peak)
 TD.10.5113                     Taoglas, Dipole Terminal Antenna SMA Connector        5.88 dBi
Table 6: Approved antenna example




DocNumber: UBX-17061097                                                                                Page 3/3



Document Created: 2017-11-10 15:37:47
Document Modified: 2017-11-10 15:37:47

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