What is UWB? Ultra-wide band is a technology that distributes the transmission power over a wide frequency range thanks to extremely short transmission pulses in the time domain. On the one hand, this reduces the power levels in such a way that UWB signals cannot interfere with other narrowband transmission methods. On the other hand, UWB devices are very robust against several simultaneously present narrowband signals: narrowband interferers can be easily filtered out due to the large bandwidth of the UWB signal in the frequency domain. A high data rate is achieved thanks to short pulses in the time domain with a high repetition rate. UWB devices are usually used at distances of up to 40 meters (130 ft).
All this gives UWB significant security advantages over previous narrowband technologies. For example, to copy the 100 kHz wide signal of a car key with a carrier frequency of 433 MHz, a simple radio relay (a briefcase with equipment for a few thousand euros) is sufficient. Copying UWB signals and then reproducing them is much more complicated, not only because of the characteristics of the UWB signal, but also because of the antenna array on the car itself, which makes it possible to determine the exact position of the car key.
UWB technology is being used in more and more industries. Here are a few examples:.
- Precise localization and tracking: Tag/anchor systems in logistics or consumer electronics, cell phones (Apple, Samsung, Huawei), automotive industry (car keys)
- digital radio transmission with very high data rate on short distances
- radars in civil (Ground Penetrating Radars, Through-Wall Imaging Systems) and military sectors (Synthetic Aperture Radars)
European Union (ETSI):
Standard: ETSI EN 302 065 (Part 1, 2, 3, 4, 5).
Part 1: Requirements for Generic UWB applications
Part 2: Requirements for UWB location tracking
Part 3: Requirements for UWB devices for ground based vehicular applications
Part 4: Material Sensing devices using UWB technology below 10,6 GHz
Part 5: Devices using UWB technology onboard aircraft
The correct classification of the corresponding standards for the respective device is crucial, as the requirements can differ greatly depending on the standard.
Standard: CFR 47 Part 15 F (Ultra-Wideband Operation), KDB 393764 D01.
Most devices that are approved on the market fall into Part 15.517 (indoor devices) and 15.519 (hand-held devices). It is very important to correctly determine the classification from the beginning, as the requirements for devices differ significantly as a result. One of the parameters here is a corresponding proof that an indoor device is really only used inside buildings and not outside (e.g. AC or LAN cable connection, no battery operation etc.).
Standard: ISED RSS-220.
It is a common misconception that the UWB frequency ranges are the same for FCC and IC. If FCC allows a UWB signal with maximum E.I.R.P. -41.3 dBm in the frequency range 3.1 GHz – 10.6 GHz, for IC the same limits apply only for the frequency range 4.75 GHz – 10.6 GHz. Since this is often not taken into account during development, expensive rework measures (firmware, recertification) can arise later.
Standard: ARIB STD-T91
The transmission bandwidth at -10 dB is at least 450 MHz.
UWB measurements are coupled with numerous challenges. You need modern spectrum analyzers with measurement bandwidths up to 50 MHz, low-noise amplifiers with high gain and at the same time lowest inherent noise, and a set of high-precision horn antennas that work in the narrow frequency ranges. But the key to success is personnel with enough competence and experience in this field. IB-Lenhardt AG has this. For UWB measurements, we have a Rohde & Schwarz FSW50 spectrum analyzer, various low-noise amplifiers from B&Z (the best models currently available), a range of horn antennas from Pasternack and Flann, as well as engineers who have successfully completed dozens of UWB test projects.