UWB – Technology and Compliance

• UWB operates across wide frequency ranges, typically between 3.1 GHz and 10.6 GHz, with regional constraints on duty cycle, band limits, or mitigation techniques (e.g. LDC, DAA).

• Devices transmit with extremely low average power (typically –41.3 dBm/MHz EIRP) and enable centimeter-level positioning based on short pulse ranging.

• Testing requires broadband antennas and gated or time-domain analysis to capture pulsed emissions and verify parameters such as TRP, duty cycle, and peak power.

• Global certification depends on firmware-based control of region-specific settings such as channel blocking, pulse modes, and geolocation restrictions.

Ultra-Wideband (UWB) transmits information using extremely short pulses spread across a wide frequency spectrum. Unlike narrowband radios such as Bluetooth or Wi-Fi, UWB is optimized for precise timing and ranging, not high data throughput.

• Modulation: Common schemes include impulse radio (IR-UWB), pulse position modulation (PPM), and BPSK. Most systems follow IEEE 802.15.4a or 802.15.4z standards.

• Bandwidth: Defined as ≥500 MHz absolute or >20% fractional bandwidth; ETSI accepts >50 MHz.

• Operating bands: Typically 3.1–10.6 GHz; specific allocations vary by region.

• Power levels: Average EIRP typically –41.3 dBm/MHz; some bands require stricter peak limits (e.g. –14 dBm in 50 MHz for FCC).

• Antennas and hardware: Devices require broadband antennas (e.g., Vivaldi or planar log-periodic) and RF frontends with consistent linearity across the UWB range.

This architecture enables robust operation in complex environments, provided that timing, antenna matching, and interference resilience are carefully engineered.

Want to see how UWB testing looks in practice?
Jump to the lab video to explore real-world testing scenarios involving car keys, smartphones, and sensor prototypes.

Ultra-Wideband technology is used across industries that require precise, low-latency localization and secure short-range communication—even in complex or interference-prone environments.

Automotive Systems

• Digital car keys: Enables secure and seamless keyless entry based on precise proximity detection.

• Vehicle-side positioning: UWB modules integrated into doors or bumpers allow accurate detection of driver approach and direction.

• Anti-relay protection: Time-of-flight measurement makes relay attacks much harder to execute.

Consumer Electronics

• Smartphones and accessories: Used for directional object finding (e.g. lost item tags), contextual data sharing, and indoor peer-to-peer positioning.

• Wearables: Smartwatches and trackers integrate UWB for secure authentication and local communication.

• AR/VR environments: Spatial tracking improves motion alignment and user interaction.

Industrial & Logistics

• Real-time location systems (RTLS): UWB anchors and tags support sub-meter tracking of assets, vehicles, and people in indoor spaces.

• Warehouse automation: Used in forklift tracking, pallet flow monitoring, and area-based access logic.

• Access control: Enables badge- or tag-based contactless zone entry and time-logging.

Specialized Applications

• Through-wall sensing: UWB is used in rescue and tactical scenarios for motion detection behind obstacles.

• Ground-penetrating radar (GPR): UWB provides high-resolution subsurface imaging in construction, archaeology, and geology.

• Drone guidance: UWB beacons assist with precise landing where GNSS is blocked or unreliable.

Thanks to its ultra-low power and wideband characteristics, UWB is ideal for precise indoor localization—even in dense, metallic, or cluttered environments.

See how UWB is implemented in real-world automotive and wearable devices.

→ Real-World Examples

Due to its extremely wide bandwidth and pulsed nature, UWB requires specialized testing approaches that differ significantly from conventional narrowband radio technologies.

Standard EMC setups are often insufficient. UWB testing must account for short pulse durations, low emission levels, and wide spectral distribution across the GHz range.

• Key parameters:
  Emission bandwidth (e.g. –10 dB and 99% occupied), peak and average EIRP per MHz, spurious emissions, pulse timing, and duty cycle.

• Measurement methods:
  UWB signals are analyzed in both time and frequency domains, often using spectrum analyzers with ≥50 MHz resolution bandwidth or time-gated oscilloscopes. Total Radiated Power (TRP) and Total Radiated Spurious (TRS) are typically measured in far-field chambers.

• Test challenges:
  Calibration across 3–10 GHz requires low-noise amplifiers, broadband antennas, and precise test setups. Devices frequently need dedicated test modes to ensure consistent emissions during measurement.

• Worst-case conditions:
  Regulatory testing is typically performed under maximum load: highest channel, full pulse repetition rate, and disabled power-saving functions.

The outcome of these tests determines whether a device complies with applicable regional UWB regulations and can proceed to certification.

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Ultra-Wideband is subject to region-specific regulatory frameworks that define permitted frequency ranges, emission limits, and mitigation requirements. While most regions adopt the –41.3 dBm/MHz average EIRP limit, the allocation of frequency bands, modulation constraints, and certification procedures vary significantly.

Ultra-Wideband devices are subject to specific design, integration, and certification-related constraints that affect hardware behavior, firmware control, and market readiness. The following aspects should be considered early in product development.

Regional Firmware Configuration

• Channel control and band limitation:
  Devices must disable regionally non-compliant frequency ranges (e.g. apply country-specific band restrictions such as China’s upcoming UWB range of 7.163–8.812 GHz).

• Mitigation settings:
  Implementing LDC or DAA mechanisms is mandatory in markets like the EU and Korea. These functions must be configurable and testable.

• Mode switching and geofencing:
  Global products often rely on software-based region switching or geolocation-controlled feature activation (e.g. disable UWB in restricted countries).

Test Mode Requirements

• Continuous transmission modes:
  Since UWB operates in short bursts, dedicated test modes are often needed to maintain a consistent signal for measurements (e.g. TRP, duty cycle).

• Worst-case conditions:
  Devices must support testing under maximum allowed emission settings (highest pulse rate, full bandwidth use, no power saving).

Integration Effects

• Antenna detuning and enclosure shielding:
  Metallic or compact housings may affect radiation patterns. Testing should be performed on the final product, not only on evaluation boards.

• Interference with co-located radios:
  Careful RF design is needed when integrating UWB with Wi-Fi, Bluetooth, GNSS, or cellular modules to minimize internal noise coupling.

• Local ID requirements:
  Market-specific identifiers (e.g. FCC ID, CMIIT ID, ANATEL code) must be applied on the product, packaging, or electronically displayed.

• End-user notices:
  Some regions require manuals to include warnings such as "indoor use only" or "not for operation near radio astronomy facilities."

• E-label options:
  Digital labeling (via menu or software) is permitted in many regions, provided it meets visibility and accessibility criteria.

Devices targeting multiple markets should plan for flexible firmware, hardware-based test access, and regulatory labeling from the earliest design stages.

These examples show how UWB technology is implemented in real-world devices across automotive, industrial, and consumer sectors—highlighting technical challenges and solutions related to integration, testing, and regulatory approval.

Automotive: Digital Car Key

Application context

An automotive manufacturer implemented UWB modules in a keyless entry system. Fixed antennas were integrated into the vehicle’s body (e.g. doors, interior), while the mobile key device was a smartphone or dedicated fob. UWB ranging enabled centimeter-level distance measurement, allowing the system to detect whether the user was directly beside the door or several meters away. Access was only granted at close range, significantly reducing vulnerability to relay attacks.

Technical implementation

The system operated on Channel 5 (6.5 GHz) with 500 MHz bandwidth and used a challenge–response protocol for authentication.

Testing and compliance

Both the vehicle installation and portable key were tested. Due to short burst transmissions, gated measurement techniques were applied. The antenna's radiation pattern was evaluated in its bumper-mounted position, where the main lobe pointed slightly upward. The system met ETSI and FCC requirements; for Japan, the pulse repetition needed firmware adaptation.

Result and impact

The system achieved unlock times under 0.2 seconds and proved reliable in dense urban environments.

Industrial: RTLS Tracking System

Application context

A logistics provider deployed a UWB-based real-time location system (RTLS) in a warehouse to track forklifts and pallets using mobile UWB tags and fixed ceiling-mounted anchors. Time Difference of Arrival (TDoA) enabled ±10 cm positioning accuracy.

Technical implementation

The system used the 7.0–8.0 GHz band with 500 MHz bandwidth. To avoid interference with 6 GHz Wi-Fi, a notch filter attenuated emissions below 7.125 GHz.

Testing and compliance

Lab tests confirmed emission peaks at 7.5 GHz and a drop-off at 6.8 GHz. The system used a low duty cycle (LDC) mode: each tag transmitted ~100 µs per second to minimize collisions. Certification succeeded in the EU, USA, and Canada. In Japan, the frequency band was not approved, so UWB was disabled via firmware.

Result and impact

The system tracked ~50 mobile units with 1 Hz update rates, demonstrating UWB’s value in industrial IoT applications with spectrum shaping and transmission control.

Consumer: UWB in Smartphones

Application context

A smartphone manufacturer integrated UWB into its flagship models for object finding and peer-to-peer data exchange. In tag-finding mode, UWB pulses from a lost-item tag were visualized via augmented reality with direction and distance. Peer interaction allowed “point-and-share” exchanges using directional handshakes.

Technical implementation

UWB operated alongside Wi-Fi, Bluetooth, and cellular radios. Pulsed operation minimized power consumption.

Testing and compliance

Thermal chamber measurements showed no significant drift under load. Certification was obtained for all major markets. A geofencing mechanism ensured that UWB was automatically disabled in regions where it is not permitted.

Result and impact

The UWB signal proved resistant to interference in crowded environments. Power optimization via pulsed transmission kept battery impact low, highlighting UWB’s flexibility in compact consumer devices.

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