The International Amateur Radio Union (IARU) represented the Amateur Service at a recent International Telecommunication Union (ITU) recent virtual meeting on the topic of wireless power transmission (WPT), attended by some 350 delegates. ITU Working Party 1A Working Group WG1A2 was of most relevance to IARU, covering the topic of WPT. The focus is on WPT’s impact on the radio spectrum.
IARU contribution centered on proposing amendments to material submitted by other delegations and a new annex that documents measurements of typical amateur signal levels, comparing these to test data from the US on non-beam WPT emission levels and to suggested limits.
“Most of the discussions on the detail were resolved with a degree of compromise, and the latest drafts will be attached to the chairman’s report for the meeting,” IARU Region 1 reported. Remaining technical issues include:
¨ Whether E-field antennas are as susceptible to WPT-EV (WPT Electric Vehicle) emissions as H-field antennas.
¨ The true noise levels in residential areas, with WPT developers claiming that WPT emissions will not be significantly above the (now-elevated) noise level.
In terms of the E-field sensitivity to WPT emissions, the proposed work plan submitted by IARU to the European Commission, for WPT-EV tests in the Joint Research Centre, included proper E- and H-field measurements.
“IARU member-society DARC [Germany] has made good progress with the rollout of its ENAMS automated noise measurement system, and IARU is now able to draw heavily on that data,” IARU Region 1 said. “The WPT Emissions document has been under discussion for some time. Here, there is no agreement yet on whether this should be a Report or a Recommendation, and the work has been carried forward to the next meeting in November 2021.”
Discussion on so-called “beam” WPT covered a range of issues, including amendments to the proposed frequencies (none are below 800 MHz). “Sadly, many proposed frequencies fall in spectrum which the Amateur Service shares with other services,” IARU said. “However, given the nature of the technology and the directivity of amateur antennas in these frequency ranges, the prospect of coexistence seems quite good.”
IARU has provided extensive input on the potential impact on radio communications resulting from spurious emissions from WPT devices. Given the planned density of WPT systems for electric vehicles operating in the 79 – 90 kHz range, widespread interference could occur to Amateur Service stations in the vicinity of WPT systems.