In this paper, a compact design of multiple-input multiple-output (MIMO) Antenna with dual sharply rejected notch bands for portable wireless ultrawideband (UWB) applications is presented and ...experimentally investigated. The proposed UWB MIMO Antenna has a compact size of 18 mm <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 34 mm. The tapered microstrip fed slot Antenna acts as a single radiating element with inverted L-shaped slits to introduce notches at wireless local area network and the IEEE INSAT/Super-Extended C-bands. The mutual coupling of less than −22 dB is achieved over the entire operating band (2.93-20 GHz). At the center of notched band, the efficiency of the Antenna drops that indicates a good interference suppression performance. The performance of the MIMO Antenna in terms of isolation among the ports, radiation pattern, efficiency, realized gain, envelope correlation coefficient, mean effective gain, and total active reflection coefficient is studied.
IEEE 802.11ax-2019 will replace both IEEE 802.11n-2009 and IEEE 802.11ac-2013 as the next high-throughput WLAN amendment. In this article, we review the expected future WLAN scenarios and use cases ...that justify the push for a new PHY/MAC IEEE 802.11 amendment. After that, we overview a set of new technical features that may be included in the IEEE 802.11ax-2019 amendment, and describe both their advantages and drawbacks. Finally, we discuss some of the network-level functionalities that are required to fully improve the user experience in next-generation WLANs and note their relation with other ongoing IEEE 802.11 amendments.
Millimeter-wave (mmWave) radar is widely used in vehicles for applications such as adaptive cruise control and collision avoidance. In this paper, we propose an IEEE 802.11ad-based radar for ...long-range radar (LRR) applications at the 60 GHz unlicensed band. We exploit the preamble of a single-carrier physical layer frame, which consists of Golay complementary sequences with good correlation properties that make it suitable for radar. This system enables a joint waveform for automotive radar and a potential mmWave vehicular communication system based on the mmWave consumer wireless local area network standard, allowing hardware reuse. To formulate an integrated framework of vehicle-to-vehicle communication and LRR, we make typical assumptions for LRR applications, incorporating the full duplex radar operation. This new feature is motivated by the recent development of systems with sufficient isolation and self-interference cancellation. We develop single- and multi-frame radar receiver algorithms for target detection as well as range and velocity estimation for both single- and multi-target scenarios. Our proposed radar processing algorithms leverage channel estimation and time-frequency synchronization techniques used in a conventional IEEE 802.11ad receiver with minimal modifications. Analysis and simulations show that in a single-target scenario, a gigabits-per-second data rate is achieved simultaneously with cm-level range accuracy and cm/s-level velocity accuracy. The target vehicle is detected with a high probability (above 99.99\%) at a low false alarm rate of 10^{-6} for an equivalent isotropically radiated power of 40 dBm up to a vehicle separation distance of about 200 m. The proposed IEEE 802.11ad-based radar meets the minimum accuracy/resolution requirement of range and velocity estimates for LRR applications.
Dorada i skladištenje lana Matin, Ana; Brandić, Ivan; Majdak, Tugomir ...
Glasnik Zaštite Bilja
47., Številka:
3.
Paper, Journal Article
Recenzirano
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Lan je jedna od najstarijih biljaka i već se tisućljećima uzgaja prije svega zbog sjemenki i vlakana. U posljednje vrijeme lan sve više koristi kao prirodni kompozit u izgradnji raznih materijala kao ...što su dijelovi automobila i slično. Dorada omogućuje uz modernu tehnologiju da vlakna lana postanu čvršća i dugovječnija te se time približava umjetno stvorenim materijalima, kao konkurent u tekstilnoj i građevinskoj industriji. Procesi dorade i skladištenja uvelike pridonose zastupljenosti lana na tržištu i popularnosti. Samom doradom utječemo i na kvalitetu sjemenki i ulja, kako u medicinske svrhe, tako i u prehrambenoj industriji. Razvojem tehnologije skladištenja lan prestaje biti kultura čija prerada završava kratko nakon žetve, već je poboljšanjem uvjeta skladištenja omogućena njegova dorada tokom čitave sezone sa minimalnom promjenom kvalitete vlakana i sjemena za daljnju doradu.
A Tutorial on IEEE 802.11ax High Efficiency WLANs Khorov, Evgeny; Kiryanov, Anton; Lyakhov, Andrey ...
IEEE Communications surveys and tutorials,
2019-Firstquarter, 2019-00-00, 20190101, Letnik:
21, Številka:
1
Journal Article
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While celebrating the 21st year since the very first IEEE 802.11 "legacy" 2 Mbit/s wireless local area network standard, the latest Wi-Fi newborn is today reaching the finish line, topping the ...remarkable speed of 10 Gbit/s. IEEE 802.11ax was launched in May 2014 with the goal of enhancing throughput-per-area in high-density scenarios. The first 802.11ax draft versions, namely, D1.0 and D2.0, were released at the end of 2016 and 2017. Focusing on a more mature version D3.0, in this tutorial paper, we help the reader to smoothly enter into the several major 802.11ax breakthroughs, including a brand new orthogonal frequency-division multiple access-based random access approach as well as novel spatial frequency reuse techniques. In addition, this tutorial will highlight selected significant improvements (including physical layer enhancements, multi-user multiple input multiple output extensions, power saving advances, and so on) which make this standard a very significant step forward with respect to its predecessor 802.11ac.
This article presents the development of a conformal reconfigurable frequency circularly polarized jute textile antenna, working at 2.4, 3.5, 5.8, and 5.9 GHz in Wi‐Fi, Wi‐MAX, Industrial, Scientific ...and Medical radio bands and W‐LAN. The antenna topology is based on a semicircular structure as the main radiating component. The conductivity is realized by using copper paint, which was brush‐painted. The patch structure is rehashed in another side of the substrate against the ground with a rotation turn 180°. Two BAR64‐03 W PIN diodes switches are placed in between a semi‐elliptical structure and a rectangular structure on the bottom side of the ground plane. By governing the state of the switches, this antenna can operate at different operating frequencies. Furthermore, the antenna has an accomplished axial ratio (AR) of less than 3 dB for resonating frequencies at all four switching states. Other electromagnetic properties of the proposed jute textile antenna accomplished in simulations were confirmed through the measurement of the antenna in an anechoic chamber. The reconfigurable circularly‐polarized jute textile antenna shows a peak gain of 4.93, 5.67, 8.86, and10.07 dBi at 2.4, 3.5, 5.8, and 5.9 GHz (Wi‐Fi, Wi‐MAX, ISM, W‐LAN).
This paper provides an overview of the most significant existing methods for indoor positioning on a contemporary smartphone. The approaches include Wi-Fi and Bluetooth based positioning, magnetic ...field fingerprinting, map aided navigation using building floor plans, and aiding from self-contained sensors. Wi-Fi and Bluetooth based positioning methods considered in this survey are fingerprint approaches that determine a user's position using a database of radio signal strength measurements that were collected earlier at known locations. Magnetic field fingerprinting can be used in an information fusion algorithm to improve positioning. The map-matching algorithms include application of wall constraints, topological indoor maps, and building geometry for heading correction. Finally, methods for step counting, step length and direction estimation, orientation tracking, motion classification, transit mode detection, and floor change detection in multi-storey buildings are discussed.
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