Over-the-air (OTA) testing evaluates and validates the RF performance of antennas within wireless devices. It is a specialised testing method that evaluates the performance of wireless communication devices without the constraints of wired connections. Unlike traditional testing approaches that involve cables with a direct connection to the device under test, OTA testing mimics real-world usage scenarios, enabling accurate assessment of a device’s wireless capabilities.
OTA testing is a regulatory requirement within the Radio Equipment Directive (RED). It is applicable to all electrical and electronic devices that intentionally emit and receive radio waves at frequencies below 3000 GHz. When the UK was still part of the EU, the RED was transposed into UK National Law in the form of the Radio Equipment Regulations 2017. The UK Government also continues to recognise CE marking, as well as UKCA marking. The requirements of the Radio Equipment Regulations 2017 are virtually identical to the RED, and there is no plan to mirror any additional requirements in the RED.
As manufacturers can validate and refine the performance of their wireless devices in real- world scenarios, this ensures that the products meet stringent quality standards, regulatory requirements, and user expectations. This type of testing allows manufacturers to identify and address issues related to signal strength, interference, antenna design, and network compatibility. From initial measurements of the device under test, adjustments can be made to the antenna or antenna matching circuitry. The manufacturer can quickly see improvements or degradation of performance. This all contributes to the production of more reliable and efficient wireless products.
OTA testing is vital to ensure that wireless devices deliver the intended user experience with reliable connectivity and high performance. It also ensures product quality, as manufacturers can identify and rectify issues related to signal quality, antenna design, and interference. This leads to more reliable and robust wireless products being developed. Total Radiated Power (TRP) and Total Isotropic Sensitivity (TIS) measurements are performed with the products operating within designed parameters and evaluated against specified standards.
Key OTA tests include:
- Wireless connectivity evaluation: OTA testing can be used to assess parameters such as signal strength, signal quality, and data transfer rates to assess how well a device can transmit and receive signals wirelessly
- Antenna performance: measurement of an antenna’s gain and efficiency provides both designers and network operators with the information needed when planning for in- service operation. Having a well-matched, efficient antenna can make a tangible difference in operating range and battery life which contributes to a better user experience
- Radiated emissions: OTA testing checks if the device complies with regulatory limits for electromagnetic radiation ensuring it doesn’t interfere with other wireless communication systems
OTA testing helps manufacturers comply with industry-specific standards and regulatory requirements set by organisations like the CTIA in the USA or the European Telecommunications Standards Institute (ETSI) in Europe. Compliance with these global standards and regulations ensures that manufacturers’ products can be legally sold and used safely without interfering with other devices.
As we continue to rely on wireless technologies for our everyday needs, OTA testing provides insights into a device’s ability to reliably operate and deliver the required performance in today’s highly used radio frequency environment.
OTA testing is a crucial step in the development and certification of wireless devices, which enables us to stay seamlessly connected in an ever-evolving digital landscape. It is not just about meeting regulatory requirements; it’s also about delivering the best possible user experience. So, the next time you use a wireless device or piece of wireless industrial equipment, it’s highly likely that its performance has been tuned and tested using an OTA chamber.
By Phil Evans, Business Development Director – Connectivity, TÜV SÜD
This article originally appeared in the February 25 magazine issue of IoT Insider.