Learning through play: an educational computer game to introduce radar fundamentals

The information exchange has evolved from traditional books to computers and Internet in a few years' time. Our current university students were born in this age: they learn and have fun with different methods as previous generations did. These digital natives enjoy computer games. Thus, designing games for learning some selected topics could be a good teaching strategy for such collective and also for undergraduate university students. This paper describes the development and test of an educational computer game revolving around radar. The objective of the game RADAR Technology is to teach students about the fundamentals of radar, while having fun during the learning experience. Based on the principle that you learn better what you practice, the authors want to induce students to discover a difficult to understand topic by proposing them a different experience, in a format better adapted to their generation skills. The computer game has been tested with actual students and the obtained results seem to be very promising

Wideband performance comparison between the 40 GHz and 60 GHz frequency bands for indoor radio channels

When 5G networks are to be deployed, the usability of millimeter-wave frequency allocations seems to be left out of the debate. However, there is an open question regarding the advantages and disadvantages of the main candidates for this allocation: The use of the licensed spectrum near 40 GHz or the unlicensed band at 60 GHz. Both bands may be adequate for high performance radio communication systems, and this paper provides insight into such alternatives. A large measurement campaign supplied enough data to analyze and to evaluate the network performance for both frequency bands in different types of indoor environments: Both large rooms and narrow corridors, and both line of sight and obstructed line of sight conditions. As a result of such a campaign and after a deep analysis in terms of wideband parameters, the radio channel usability is analyzed with numerical data regarding its performance

Non specular reflection and depolarisation due to walls under oblique incidence

Non

RMS delay spread vs. coherence bandwidth from 5G indoor radio channel measurements at 3.5 GHz band

Our society has become fully submersed in fourth generation (4G) technologies, setting constant connectivity as the norm. Together with self-driving cars, augmented reality, and upcoming technologies, the new generation of Internet of Things (IoT) devices is pushing the development of fifth generation (5G) communication systems. In 5G architecture, increased capacity, improved data rate, and decreased latency are the objectives. In this paper, a measurement campaign is proposed; we focused on studying the propagation properties of microwaves at a center frequency of 3.5 GHz, commonly used in 5G cellular networks. Wideband measurement data were gathered at various indoor environments with different dimensions and characteristics. A ray-tracing analysis showed that the power spectrum is dominated by the line of sight component together with reflections on two sidewalls, indicating the practical applicability of our results. Two wideband parameters, root mean square delay spread and coherence bandwidth, were estimated for the considered scenarios, and we found that they are highly dependent on the physical dimension of the environment rather than on furniture present in the room. The relationship between both parameters was also investigated to provide support to network planners when obtaining the bandwidth from the delay spread, easily computed by a ray-tracing tool

Electromagnetic characterization of cola drinks

The electromagnetic characterization of liquids could be of great interest to manufacturing companies, as it could provide information about the quality of beverages. They could use this knowledge to optimize production processes. Using the probe reflection system, dielectric properties of different varieties of Coca-Cola and Pepsi products in cans have been examined. Measurements have been performed at several temperatures between 0 and 60 degrees Celsius and at periods after opening of 0, 6, 24 and 48 h. The applied frequency range goes from 0 to 20 GHz in steps of 200 Hz. Both experimental and theoretical approaches have been used to model the results. Although all varieties follow the same trend, the results clearly show that differences exist in the electromagnetic behavior of the two brands and of the different varieties. (C) 2017 Elsevier Ltd. All rights reserved

3-D Mechanically Tunable Square Slot FSS

We introduce an innovative 3-D mechanically tunable frequency selective surface (FSS), which is inspired by the classical flat square slot FSS. The proposal improves the performance of classical 2-D FSS designs, and it also represents a novel method of achieving mechanical frequency tuning, despite other 3-D designs that consist of a collection of stacked 3-D layers exist. In our proposal, the rotation of an inner element provides tuning capability to the squared cell structure, consisting of metallic grids with a movable inner element. An aluminum prototype was built, which can be tuned from 2.4 to 4 GHz, and also compared its measured performance and numerical simulations. Some characteristics of the proposed structure are the rejection level at main polarization, up to 20 dB, and the maximum frequency sweep of approximately 50% of the fundamental frequency. The prototype showed a stable frequency response for angles of incidence up to 45°. Since results are in good agreement with simulations, we provide parametric equations to design 3-D structures at desired frequencies.info:eu-repo/semantics/publishedVersio

Car Bumper Effects in ADAS Sensors at Automotive Radar Frequencies

Radars in the W-band are being integrated into car bumpers for functionalities such as adaptive cruise control, collision avoidance, or lane-keeping. These Advanced Driving Assistance Systems (ADAS) enhance traffic security in coordination with Intelligent Transport Systems (ITS). This paper analyzes the attenuation effect that car bumpers cause on the signals passing through them. Using the free-space transmission technique inside an anechoic chamber, we measured the attenuation caused by car bumper samples with different material compositions. The results show level drops lower than 1.25 dB in all the samples analyzed. The signal attenuation triggered by the bumpers decreases with the frequency, with differences ranging from 0.55 dB to 0.86 dB when comparing the end frequencies within the radar band. Among the analyzed bumper samples, those with a thicker varnish layer or with talc in the composition seem to attenuate more. We also provide an estimation of the measurement uncertainty for the validation of the obtained results. Uncertainty analysis yields values below 0.21 dB with a 95% coverage interval in the measured frequency band. When comparing the measured value with its uncertainty, i.e., the relative uncertainty, the lower the frequency in the measured band, the more accurate the measurements seem to be