Why ART-Fi’s RF Wideband Vector Probe Array Technology is a Must for Human Exposure Assessment?

Measuring wideband signals: from past narrowband scalar approach to modern RF wideband vector technology

    Nowadays, wireless communication signals are wideband while historical SAR assessments were narrowband and limited. This contradiction generates failures on SAR quality control and additional complexities including important costs and constraints in the industrial telecommunication innovation dynamics. In parallel, the complex evolution of electromagnetic signals coupled with consumers growing demand on transparency are emboldening the necessity to measure more wireless devices with high measurement precision. In order to satisfy both the industry and the consumers demands, RF wideband vector probe array technology is a must.

    From the fundamental scientific basis, an electromagnetic wave is defined by an amplitude and a phase characterizing its propagation through a media and varying both in time and frequency. As a matter of fact, a fast and accurate measurement must directly access to the amplitude, phase, frequency and time information.

    Unsatisfactorily, from the end of the 90s historical SAR measurements are based on diode components. That only provide an estimate of the amplitude and use non-physical interpolation and extrapolation processes. This fundamental limitation cannot support fast and accurate measurement with the high demanding requirements for modern signals such as 5G. In 5G communications, mobile devices can emit simultaneously at different frequencies. Narrowband measurement systems mix up all the signal contributions without discriminating any frequency component. To compensate this limitation, narrowband systems complexify the measurement process which raise costs and delays for mobile makers and inaccuracies of the measurements. Moreover, additional limits were already identified by overestimating SAR values due to artificial computations and non-realistic measurement emission modes. This arises a doubt for both consumer’s satisfaction and the industry needs. Fortunately, there is a solution now.

    Intrinsically, RF wideband vector probe array technology measures each emitted frequency in a precise and independent way along with the amplitude, phase and time dependency. Measuring wideband signals with wideband measurement systems is finally possible. A strong disruptive challenge is to measure the SAR/PD[i] in a fast and accurate way. ART-Fi created and designed the disruptive RF Vector wideband measurement system ART-MAN [1]. This system is composed of wideband RF antenna arrays coupled with a real-time super-heterodyne architecture applying a synchronous phase-coherent time-domain signal acquisition. ART-MAN is the only science-based vector system able to measure any electromagnetic wave accurately and rapidly. It directly measures a signal’s amplitude, phase, time-frequency dependence and adapts natively to any signal complex modulation.

   For usual multiple-frequency signals, the vector wideband system ART-MAN measures rigorously each frequency component without any approximate approaches[ii]. This RF vector’s reliability is ensured exclusively by using the laws of Physics. It is the only way to characterize a wireless a device in its real emission modes. The antenna performances can be improved with a better characterization while preserving the human exposure. RF Vector wideband systems are a part of  a new standard [2] for SAR compliance.

    This disruptive technology is already used worldwide and adopted by a large panel of industrial experts. It allows to test each mobile directly in the production line to avoid SAR market recalls from regulators and provides transparent information to the consumers. RF Vector wideband systems are strong allies at every life step of wireless devices.

    Modern Vector Wideband systems are must-have solutions to solve 5G technical challenges and beyond…like 5G-mmW.

    Please contact us to get your customized ART-Fi solution.

[1]  « ART-MAN system », ART-Fi. https://www.art-fi.eu/solutions/sar-measurement-systems/art-man-rf-system.

[2]  « IEC 62209-3:2019 Measurement procedure for the assessment of specific absorption rate of human exposure to radio frequency fields from hand-held and body-mounted wireless communication devices - Part 3: Vector measurement-based systems (Frequency range of 600 MHz to 6 GHz) », sept. 2019. https://webstore.iec.ch/publication/30773.

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[i] SAR: Specific Absorption Rate. PD: Power Density.

[ii] Diode-systems are based on algorithms relying on not physical summations, interpolations and extrapolations.