u blox JODYW164 WLAN/Bluetooth host-based multiradio module JODY-W1 User Manual Antenna Reference Design Guide

u-blox AG WLAN/Bluetooth host-based multiradio module JODY-W1 Antenna Reference Design Guide

Contents

Antenna Reference Design Guide

JODY-W1 antenna reference design
UBX-18017767 Page 1 of 3
JODY-W1 antenna reference design
Topic :
JODY-W1 antenna reference design
Doc.No:
UBX-18017767
Revision
R01
Date:
Name
Signature
Created
24-Apr-2018
Stefan May
smay
Checked
Released
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. © 2018 u-blox AG
1 Scope
This document defines the essential specifications necessary to implement the JODY-W1 antenna
reference designs. It is part of the equipment certification application issued to FCC and IC. 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
JODY-W164-03A
XPYJODYW164
JODY-W164-07A
XPYJODYW164-07A
Table 1: FCC and IC IDs for different models of JODY-W1 series
3 General description and requirements
JODY-W1 series module provides three RF interfaces for connecting the external antennas.
Antenna ports ANT0 and ANT1 have a nominal characteristic impedance of 50 Ω and must be
connected to the related antenna through a 50 Ω 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.
The ANT2 antenna port is not used on the JODY-W164-03A and JODY-W164-07A modules.
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.
JODY-W1 antenna reference design
UBX-18017767 Page 2 of 3
Item
Requirements
Remarks
Impedance
50 nominal characteristic
impedance
The impedance of the antenna RF connection must match
the 50 impedance of Antenna pins.
Frequency Range
2400 - 2500 MHz
5150 - 5850 MHz
For 802.11b/g/n and Bluetooth.
For 802.11a/n/ac.
Return Loss
S11 < -10 dB (VSWR < 2:1)
recommended
S11 < -6 dB (VSWR < 3:1) acceptable
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 antenna pins.
The impedance of the antenna termination must match as
much as possible the 50 nominal impedance of antenna
pins over the operating frequency range, to maximize the
amount of 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 antenna input: the efficiency is a
measure of how well an antenna receives or transmits.
Maximum Gain
The maximum antenna gain must not exceed the value
specified in type approval documentation to comply with
regulatory agencies radiation exposure limits.
Table 2: Summary of antenna interface requirements
Item
Requirements
Remarks
Isolation
(in-band)
S21 > 25 dB recommended
S21 > 20 dB acceptable
The antenna to antenna isolation is the S21 parameter
between the two antennas in the band of operation.
Isolation
(out-of-band)
S21 > 35 dB recommended
S21 > 30 dB acceptable
Out-of-band isolation is evaluated in the band of the
aggressor to ensure that the transmitting signal from
the other radio is sufficiently attenuated by the receiving
antenna to avoid saturation and intermodulation effect
at the receiver’s port.
Envelope
Correlation
Coefficient (ECC)
ECC < 0.1 recommended
ECC < 0.5 acceptable
The ECC parameter correlates the far field parameters
between antennas in the same system. A low ECC
parameter is fundamental to improve performance in
MIMO-based systems.
Table 3: Summary of MIMO and Wi-Fi/Bluetooth coexistence 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. The specification can be found in Table 4. The two coplanar ground planes
beside the signal trace should be connected to the lower ground plane using vias (illustrated in
Figure 2). It is recommended that this vias are placed with a maximum distance of 0.5 mm to the
coplanar ground edge and a maximum pitch of 2 mm. The top side should be coated with generic
LPI solder stop mask. The antenna traces should have a minimum distance of 20 mm, preferably
more, to ensure the required antenna to antenna isolation.
The SMA connector is used to mount an antenna. For Bluetooth and Wi-Fi operation in the 2.4 GHz
band and Wi-Fi operation in the 5 GHz band, the module has been tested and approved for use with
antennas up to 2 dBi antenna gain.
JODY-W1 antenna reference design
UBX-18017767 Page 3 of 3
Figure 1: Coplanar micro-strip dimension specification
Item
Value
S
300 µm
W
650 µm
T
35 µm
H
400 µm
4.3
Table 4: Coplanar micro-strip specification
The mechanical dimensions and position of the components are specified in Figure 2. The layers
beneath the ‘top layer’ have the same dimensions and are filled with ground. No RF traces are
routed in those layers.
Figure 2: Mechanical dimensions of JODY-W1 antenna reference design, top layer. Antenna ports from top to bottom:
ANT1, ANT0, ANT2.
The ANT2 antenna port is not used on the JODY-W164-A modules.

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