ST AN5622, B-UWB-MEK1 User Manual
AN5622
Application note
B-UWB-MEK1 antenna offset adjustment
Introduction
B-UWB-MEK1 boards have an SMA connector as UWB output. The module is calibrated so that the distance measure starts at
the SMA output.
When plugging an antenna with a connector, this reference point changes and offsets the distance measurement. Therefore, the
system must take into account specific offset values, which depend on the antenna and connector types.
The B-UWB-MEK1 standard and extension kits are delivered with omnidirectional antennas and SMA male‑male connectors.
The offset for this configuration is 31 cm. This is the default value in MOD1/MEK1 programming tool applied to each board.
This application note complements the information available in the SDK. It is intended for advanced users already familiar with
the quick start guide. It is based on system version 3.x.
Figure 1. B-UWB-MEK1 board with an omnidirectional antenna
Omni-directional antenna
SMA male-male connector
UWB output
AN5622 - Rev 1 - April 2021
For further information contact your local STMicroelectronics sales office.
www.st.com
1 General information
B-UWB-MEK1 embeds the B-UWB-MOD1, which features the STM32L476JE 32-bit microcontroller based on the
Arm® 32-bit Cortex®‑M4 processor.
Note: Arm is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.
Definitions
Table 1 presents the definition of acronyms that are relevant for a better understanding of this document.
Table 1. List of acronyms
Term Definition
3D_SELF 3D single self-positioning
BLR Beacon-listening rate
HF Hyperframe
PHS Protocol hyperframe size
PSN Protocol slot number
PSS Protocol slot size
RTLS Real‑time locating system
RV Rendez-vous (slot and zone)
SF Superframe
SFI Superframe information
TDMA Time-division multiple access
UWB Ultra-wideband
AN5622
General information
References
Refer to the following documents for an introduction to the B-UWB-MEK1 and B-UWB-MOD1 products in indoor
location systems:
• Ultra-wideband module for high-precision indoor location (DB4404)
• Evaluation kit for the B-UWB-MOD1 ultra-wideband module (DB4392)
• B-UWB-MEK1 quick start guide (UM2798)
• SDK advanced documentation
Demonstration software
Contact the local STMicroelectronics sales office or distributor (refer to www.st.com) for the latest software and
associated documentation.
AN5622 - Rev 1
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2 Offset adjustment
2.1 Find the offset
AN5622
Offset adjustment
Table 2. Find the offset
Antenna
Additional
connector
Component
Omni-directional with
original SMA connector
Directional with
original connector
SMA male‑male
SMA female‑male right
angle
Attenuator
Offset (in cm)
Ch1 Ch2 Ch3 Ch4
26 31 27 37
29 37 26 50
3
Cable
Average factor
Measurement on a network vector analyzer
Offset of
two SMA
wire‑male
connectors
included
Real cable length (in cm) × 1.49
Group delay (in s) × C (in m.s-1) × 100
(C = 299 792 458 m.s-1)
AN5622 - Rev 1
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