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JournalISSN: 1759-0787

International Journal of Microwave and Wireless Technologies 

Cambridge University Press
About: International Journal of Microwave and Wireless Technologies is an academic journal published by Cambridge University Press. The journal publishes majorly in the area(s): Antenna (radio) & Microstrip antenna. It has an ISSN identifier of 1759-0787. Over the lifetime, 1758 publications have been published receiving 10950 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the state-of-the-art of millimeter-wave interactions with the human body is presented. But the authors mainly focus on recent results and advances related to the different aspects of different aspects.
Abstract: The biocompatibility of millimeter-wave devices and systems is an important issue due to the wide number of emerging body-centric wireless applications at millimeter waves. This review article provides the state of knowledge in this field and mainly focuses on recent results and advances related to the different aspects of millimeter-wave interactions with the human body. Electromagnetic, thermal, and biological aspects are considered and analyzed for exposures in the 30-100 GHz range with a particular emphasis on the 60-GHz band. Recently introduced dosimetric techniques and specific instrumentation for bioelectromagnetic laboratory studies are also presented. Finally, future trends are discussed.

234 citations

Journal ArticleDOI
TL;DR: The problem of unmanned aerial vehicles classification using continuous wave radar using micro-Doppler signature is considered and it provides capability of correct classification with a probability of around 95%.
Abstract: The popularity of small unmanned aerial vehicles (UAVs) is increasing. Therefore, the importance of security systems able to detect and classify them is increasing as well. In this paper, we propose a new approach for UAVs classification using continuous wave radar or high pulse repetition frequency (PRF) pulse radars. We consider all steps of processing required to make a decision out of the raw radar data. Before the classification, the micro-Doppler signature is filtered and aligned to compensate the Doppler shift caused by the target's body motion. Then, classification features are extracted from the micro-Doppler signature in order to represent information about class at a lower dimension space. Eigenpairs extracted from the correlation matrix of the signature are used as informative features for classification. The proposed approach is verified on real radar measurements collected with X-band radar. Planes, quadrocopter, helicopters, and stationary rotors as well as birds are considered for classification. Moreover, a possibility of distinguishing different number of rotors is considered. The obtained results show the effectiveness of the proposed approach. It provides the capability of correct classification with a probability of around 92%. © Cambridge University Press and the European Microwave Association 2014.

210 citations

Journal ArticleDOI
TL;DR: In this article, the authors review the most recent degradation modes and mechanisms observed in AlGaN/GaN, as resulting from a detailed accelerated testing campaign, based on reverse bias tests and DC accelerated life tests at various temperatures.
Abstract: In the present paper we review the most recent degradation modes and mechanisms recently observed in AlGaN/GaN (Aluminum Gallium Nitride/Gallium Nitride). High Electron-Mobility Transistors (HEMTs), as resulting from a detailed accelerated testing campaign, based on reverse bias tests and DC accelerated life tests at various temperatures. Despite the large efforts spent in the last few years, and the progress in mean time to failure values, reliability of GaN HEMTs, and millimeter microwave integrated circuits still represent a relevant issue for the market penetration of these devices. The role of temperature in promoting GaN HEMT failure is controversial, and the accelerating degradation factors are largely unknown. The present paper proposes a methodology for the analysis of failure modes and mechanisms of GaN HEMTs, based on (i) DC and RF stress tests accompanied by an (ii) extensive characterization of traps using deep level transient spectroscopy and pulsed measurements, (iii) detailed analysis of electrical characteristics, and (iv) comparison with two-dimensional device simulations. Results of failure analysis using various microscopy and spectroscopy techniques are presented and failure mechanisms observed at the high electric field values typical of the operation of these devices are reviewed.

115 citations

Journal ArticleDOI
TL;DR: An extensive thorough investigation of diversity and mutual coupling (correlation) reduction techniques in compact MIMO antennas is carried out.
Abstract: Multiple input multiple output (MIMO) antenna is at core of the presently available wireless technologies. The design of MIMO antennas over a limited space requires various approaches of mutual coupling reduction, otherwise gain, efficiency, diversity gain, and radiation patterns will be severely affected. Various techniques have been reported in literature to control this degrading factor and to improve the performance of the MIMO antennas. In this review paper, we have carried out an extensive thorough investigation of diversity and mutual coupling (correlation) reduction techniques in compact MIMO antennas.

110 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the beam tilts on the correlation coefficient was investigated for N-port antennas using only the radiation efficiency and the S-parameters of the antenna.
Abstract: The correlation coefficient (ρ) is an important metric for the evaluation of multiple-input–multiple-output (MIMO) antenna systems because it describes the relationship between the channels in a particular propagation environment. Highly correlated channels will degrade the MIMO system performance. Various methods to calculate ρ are analyzed in this work using three different types of antennas with different efficiencies and radiating properties. While the field-based method for finding ρ gives the most accurate results and should be used all the time. It is independent of antenna efficiency. The the S-parameter-based method might give reasonable results only when the antenna efficiency is very high and the patterns are separated in space, but in most cases, it underestimates ρ values and thus is not a reliable method and should be avoided. Incorporating the antenna efficiency can improve the ρ estimates using the S-parameters method under some specific conditions. The equivalent circuit method provides reasonable results for symmetric antenna structures only, and is the most complex in formulation. As part of the evaluation, two existing methods incorporating the radiation efficiency of the antennas are generalized to N-ports for the first time. Although less accurate than the field-based method, these extensions allow the evaluation of ρ for N-port antennas using only the radiation efficiency and the S-parameters of the antenna. The effect of the beam tilts on ρ estimation is investigated for the first time.

68 citations

Performance
Metrics
No. of papers from the Journal in previous years
YearPapers
202393
2022223
2021216
2020122
2019125
2018116