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 IC ID JODY-W164-03A XPYJODYW164 8595A-JODYW164 JODY-W164-07A XPYJODYW164-07A 8595A- JODYW16407A 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.

Navigation menu