EMC Measurement Setup Based on Near-Field Multiprobe System

Multiprobe spherical near-field measurement is a potent tool for fast and accurate characterization of electrical properties of antennas. The use of fast switching in one axis, an azimuth positioner, and a near- to far-field transformation allows a substantial time reduction in antenna measurements while maintaining high-quality results. On the other hand, conventional emissions EMC measurement systems are typically based on detecting the radiated spurious emissions by a device at different frequencies. The systems usually work in far-field (or quasi-far-field conditions), performing the measurements either at 3 or 10 meters. Measurements under these conditions take space and time. Moreover, the systems are not cost-effective for pre-compliance purposes where pre-testing of the device should provide valuable information and confidence about the DUT before performing a compliance test. This chapter analyzes the possibility of cost and space reduction for EMC systems based on multiprobe near-field measurement systems in combination with OTA (over the air measurements), reference-less systems, spherical near-field transformation, phase reconstruction, modal filtering, source reconstruction, and software-defined radio receivers.

MOMSTER, a Europlanet-funded public engagement project

<p>In May 2020, Europlanet Society launched a call to fund projects to engage the public with planetary science. Our project proposal called MOMSTER: MObile Meteor STation for Education & outReach was amongst the three projects that were granted.</p> <p>MOMSTER aims at developing a Meteor Education Kit as a resource for STEAM (Science, Technology, Engineering, Arts, Mathematics) teachers in secondary schools. The kit includes a mobile radio meteor station consisting of a dedicated antenna and radio receiver, as well as an educational package to learn all about meteors and their detection methods, while at the same time conveying a fascination for the ephemeral beauty and complexity of these natural light shows. The project goals are stimulating STEAM (ultimately resulting in nudging future career choices towards science or engineering career paths) and the use of citizen science (especially the Radio Meteor Zoo initiative on the online citizen science platform Zooniverse) at schools, and reaching the general public.</p> <p>The development of educational resources builds upon preliminary experiences we gained by participating in an Erasmus+ project called BRITEC (Bringing Research into ThE Classroom), in which teachers and pupils participated in the Radio Meteor Zoo activity.  We are presently in a pilot phase where three Belgian schools (two Dutch speaking and one French speaking) test the mobile radio meteor station and the educational resources, and give their feedback.</p> <p>We are using STEAM-education as an approach to broaden our target group towards less scientifically oriented students. We do this by developing an educational resource on visual (science) communication. We also organized an art & design competition for high school students with more than 30 submissions. The best piece of art will decorate the ‘MOMSTER boxes’ we use for transport of the radio receivers.</p>

Investigation of Attenuation and Directional Characteristics of Millimeter Wave Propagation in Urban Environment Using Ray Tracing Technique

Future high densification wireless networks come with high handoff rates, which require knowledge of mobile speed. Mobile speed estimation is crucial for optimizing handover to reduce call drops and network signaling flow, optimize traffic scheduling, improve quality of service, achieve resource optimization, mobility load balancing, channel quality feedback enhancement, and energy efficiency. In this paper, we present a low complexity mobile speed estimation model using count of peaks and troughs of the received signal envelop. We simulated the model in Matlab® and our result shows that the model has a maximum error of 0.25 m/sec. The model has two advantages. First, it does not require measurement of the received signal power; it only counts envelop peaks and troughs. Second, the model is independent of dc offset inherent in the radio receivers. However, the model has one limitation- it does not give the crossing component of a mobile’s velocity.

A possible radio anomaly observed on the occasion of the MW=6.0 earthquake occurred in Dodecanese islands at the end of January 2020

<p>Since 2009, several VLF/LF radio receivers have been installed throughout Europe in order to realize a European radio network for studying the radio precursors of earthquakes, called the INFREP network. The current network has nine VLF/LF receiving stations, two in Romania and<br>Greece, one in Italy, Austria, Portugal, Cyprus, and Serbia. The receivers can measure with 1 min sampling rate the intensity of 10 radio signals in the band VLF (10-50 kHz) and LF (150-300 kHz). The scope of existing transmitters is manifold, e.g. they are used for radio broadcast (LF), for radio-navigation or time signals and mainly for military purposes in the VLF range. At the end of January 2020 an intense seismic crisis occurred in Dodecanese Islands; the main event (Mw= 6.0) occurred on January 30. This seismic activity occurred in the "sensitive" area of the INFREP network. The analysis of the data collected by INFREP receivers has revealed clear anomalies in three VLF signals appearing some days before the main earthquake. The anomalies appear in the trends collected by the Cyprus receiver and the epicenter is inside the 5<sup>th</sup> Fresnel ellipses defined by transmitters-receiver. Here we report the data analysis and we present in detail the anomalies. The possibility that they are precursors of the quoted earthquake seems significant.</p><p>Biagi, P.F., Colella, R., Schiavulli, L., Ermini, A., Boudjada, M., Eichelberger, H., Schwingenschuh, K., Katzis, K., Contadakis, M.E., Skeberis, C., Moldovan, I.A. and Bezzeghoud, M. (2019) The INFREP Network: Present Situation and Recent Results. Open Journal of Earthquake Research,8, 101-115. https://doi.org/10.4236/ojer.2019.82007</p>

Electromagnetic Safety of Remote Communication Devices—Videoconference

Devices powered by electricity become sources of electromagnetic emissions in the course of their operation. In the case of devices oriented to process information, these emissions can have a character of revealing emissions, i.e., those whose reception and analysis allow for remote reconstruction of related data. The best known example of this phenomenon is the formation of revealing emissions during the operation of imaging devices: monitors, projectors or printers. Increasingly more often, these components are used for communication in the form of videoconferences with other network users. The article presents the result of tests and analyses of threats related to the use of such solutions (monitors, personal computers, VoIP terminals) for the confidentiality of conversations and the data presented during them. The focus is on video signals; however, the potential possibilities of revealing speech signals were also indicated. Such phenomenon causes a huge threat to data confidentiality because the combination of graphics and sound can undoubtedly contain much more information about the protected data than just graphics or sound separately. The presented results of analyses apply to graphic data, possibilities of non-invasive acquisition of such data, similarity of images and of patterns and reconstructed image and image recognition. The results indicate that there is still a risk of loss of data confidentiality due to a phenomenon of an electromagnetic leakage, and specialized instrumentation is not required for its interception under favorable circumstances. This may particularly apply to audio data that may be accidentally received by home radio receivers. In particular, the presented results of analyses apply to a Special Issue of Symmetry which is characterized by security and privacy in communication systems and networks, signal processing, video and image processing, multimedia communications and electromagnetic compatibility. All these scientific and technical areas have either symmetrical or asymmetrical approaches, and they have to be taken into consideration as a whole in order to choose the best combinations to protect processed information.

Methods of complex signal analysis for testing radio receiving equipment

In this paper, we consider methods for evaluating the quality of signals from special purpose digital radio receivers. We talk about the issues of increasing the reliability of the equipment due to the expansion of methods for complex analysis of signals during testing. The article pre-sents methods and algorithms for identifying distortions of signals based on the methods for wavelet analysis.Considered the existing technique for determining the harmonic distortion of a signal when testing digital radio-receiving equipment of a special purpose, based on the Fou-rier transform. Its shortcomings are shown in the analysis of rapidly changing signals. As an alternative, a technique for analyzing non-stationary signals based on wavelet transform was proposed, and a new criterion for estimating the harmonic distortion of signals, the distortion coefficient, was introduced.