AN1195: Antenna Array Design Guidelines
for Direction Finding
In January 2019, the Bluetooth SIG announced support for Angle of Arrival (AoA) and
Angle of Departure (AoD) in the Bluetooth 5 specification. AoA and AoD can be used
for building RF-based real-time locationing systems and applications, based on phase-
based angle estimation algorithms. Application use cases for the Internet of Things
(IoT) are tracking of assets and people, as well as indoor locationing and wayfinding.
The purpose of this application note is to provide hardware design guidelines specific
to the antenna arrays required for the direction finding implementations.
KEY POINTS
• Describes general direction finding use
cases
• Provides general antenna
recommendations for a direction finding
antenna array
• Details 4x4 antenna array properties and
insight into antenna tuning and items
which affect the antenna
silabs.com | Building a more connected world. Copyright © 2022 by Silicon Laboratories Rev. 0.4
1. Device Compatability
This application note applies to 2.4 GHz Bluetooth Low Energy (BLE) standards for the following devices:
EFR32 Gecko Series 2:
• EFR32BG22, EFR32MG22
• EFR32BG24, EFR32MG24
The antenna array board presented in this application note (BRD4191A) is designed with EFR32BG22 SoC, but it is applicable to each
of the EFR32 families listed above. Refer to the device data sheets for the complete list of supported part numbers.
AN1195: Antenna Array Design Guidelines for Direction Finding
Device Compatability
silabs.com | Building a more connected world. Rev. 0.4 | 2