10.3.2.1 Antenna Placement and Routing
The antenna is the element used to convert the guided waves on the PCB traces to the free space
electromagnetic radiation. The placement and layout of the antenna are the keys to increased range and data
rates.
provides a summary of the recommended antennas to use with the CC3220MODx module.
Table 10-2. Antenna Guidelines
SR NO.
GUIDELINES
1
Place the antenna on an edge or corner of the PCB.
2
Ensure that no signals are routed across the antenna elements on all the layers of the
PCB.
3
Most antennas, including the chip antenna used on the LaunchPad
™
, require ground
clearance on all the layers of the PCB. Ensure that the ground is cleared on inner layers
as well.
4
Ensure that there is provision to place matching components for the antenna. These
must be tuned for best return loss when the complete board is assembled. Any plastics
or casing must also be mounted while tuning the antenna because this can impact the
impedance.
5
Ensure that the antenna impedance is 50 Ω because the module is rated to work only
with a 50-Ω system.
6
In case of printed antenna, ensure that the simulation is performed with the solder mask
in consideration.
7
Ensure that the antenna has a near omnidirectional pattern.
8
The feed point of the antenna is required to be grounded. This is only for the antenna
type used on the CC3220MODx Launchpad. See the specific antenna data sheets for
the recommendations.
9
To use the FCC certification of the module, refer to the
wiki page on CC3220MODx Radio certification
lists the recommended antennas to use with the CC3220MODx module. Other antennas may be
available for use with the CC3220MODx modules. See the
CC3120 and CC3220 Radio Certifications
Table 10-3. Recommended Components
CHOICE
PART NUMBER
MANUFACTURER
NOTES
1
AH316M245001-T
Taiyo Yuden
Can be placed on edge of the PCB and uses much
less PCB space
10.3.2.2 Transmission Line Considerations
The RF signal from the module is routed to the antenna using a Coplanar Waveguide with ground (CPW-G)
structure. CPW-G structure offers the maximum amount of isolation and the best possible shielding to the
RF lines. In addition to the ground on the L1 layer, placing GND vias along the line also provides additional
shielding.
shows a cross section of the coplanar waveguide with the critical dimensions.
Figure 10-4. Coplanar Waveguide (Cross Section)
SWRS206E – MARCH 2017 – REVISED MAY 2021
70
Copyright © 2021 Texas Instruments Incorporated
Product Folder Links: