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Design and Analysis of a Hybrid Circularly Polarized Multi-Band MIMO Antenna for Sub 6 GHz Applications

Salma S., Khan Habibulla, Madhav B. T. P., Sandeep D. Ram, Suman M.

International Journal of Electronics and Telecommunications

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2021

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Vol. 67, No. 4

570--577

EN

In this article, a hybrid circularly polarized Multiple-Input Multiple-Output (MIMO) antenna for multi-band operation from 2.3 to 9.2 GHz with an impedance bandwidth of 7 GHz is proposed and investigated experimentally. The designed MIMO antenna model has a compact size of 20mm×40mm×1.6mm on the FR-4 substrate. The microstrip feed of the proposed slot antenna consists of a tapered structure, and the radiating element consists of the inverted L- shaped slots, which were opened on both sides of the radiating elements to introduce notches at the sub-6 GHz frequencies. L-shaped stubs are also introduced on another side of the substrate in the common ground plane to attain high isolation between the radiating elements of the proposed antenna. In the operating band from 2.3 to 9.2 GHz, isolation of less than -20 dB is achieved by the proposed model. The performance of the circularly polarized MIMO antenna in terms of RHCP and LHCP radiation patterns, axial ratio, surface current distributions, isolation between the ports, diversity gain (DG), envelope correlation coefficient (ECC), total active reflection coefficient (TARC), and peak gain are studied and presented in this work. The obtained characteristics of the proposed antenna make it suitable for sub-6-GHz frequency applications.

2

Strategic environmental assessment of spatial plans in the light of own research

Harasymiuk Jolanta, Drozd Wojciech

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2019

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Vol. 28, No. 2

224--234

EN

Strategic environmental assessment constitutes the least explored in research kind of an environmental assessment in comparison to environmental impact assessment and habitat assessment. The introduction of a strategic assessment was to ensure the completeness of the assessment system of environmental impact in investment processes and to guarantee a consideration for the principle of caution in early stages of these processes. In the current legal situation, a strategic environmental assessment should anticipate a preparation of commune’s planning documents or making changes in such documents. In the case of local plans constituting minor changes of earlier-accepted documents, a strategic assessment is not made. As a result a strategic environmental assessment may be conducted in a limited scope in numerous communes. Additionally, a sketchy character and ambiguity of the regulations concerning strategic environmental assessments result in a lack of understanding for the necessity of conducting such assessments among investors and community. The aim of this article is to work out methods for strategic environmental assessment of the projects of local plans and to examine which methods of environmental impact assessment have been used in the prognoses of environmental impact, i.e. in the basic assessment documents. The research made shows that the quality of documents prepared for the need of strategic assessments is unsatisfactory in the aspects of methodology.

3

Experimental studies on impact of CFRP tubes structure on amount of absorbed energy under dynamic conditions

Ryzińska G., Gieleta R.

Composites Theory and Practice

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2018

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R. 18, nr 4

196--201

EN

The aim of this work is to examine the effect of the layer configuration (lay-up) of carbon 3k/IMP503Z40 epoxy composite elements on the specific energy absorption (SEA) effect in the process of progressive crushing of composite tubes. Composite tubes made of Impregnatex Compositi prepreg with a dry areal weight of 160 g/m2 plain weave and unidirectional prepreg (UD) 200 g/m2 on an epoxy matrix were tested. The resin content in both prepregs was 47%. Using these two materials, tubes with different ratios of axial and hoop fibers, in two sizes with an inner diameter of 42 and 20 mm while maintaining a constant ratio of wall thickness to a diameter of 0.05 were made. The samples were unilaterally chamfered at the angle of 70°. Then, tests of progressive crushing of the samples under dynamic conditions by means of a drop tower and an additional initiator were performed. A new factor was introduced to describe the mass fraction of the axial fibers. SEA was calculated, which indicated that the higher the share of axial fibers, the greater the SEA for both types of samples and it was indicated that there may be a scale effect.

PL

Celem niniejszej pracy jest zbadanie wpływu konfiguracji warstw elementów kompozytowych włókno węglowe 3k/żywica epoksydowa IMP503Z40 na efekt pochłaniania energii (SEA) w procesie progresywnego niszczenia rur kompozytowych. Badano rury kompozytowe wykonane z preimpregnatu firmy Impregnatex Compositi o gramaturze suchej tkaniny 160 g/m2 o splocie płóciennym oraz preimpregnatu jednokierunkowego (UD) 200 g/m2 na osnowie epoksydowej. Zawartość żywicy w obu preimpregnatach wynosiła 47%. Wykorzystując te dwa materiały, wykonano rury o różnym stosunku ilości włókien osiowych do obwodowych, w dwóch rozmiarach o średnicy wewnętrznej 42 mm oraz o średnicy wewnętrznej 20 mm, zachowując stały stosunek grubości ścianki do średnicy wynoszący 0,05. Próbki jednostronnie fazowano pod kątem 70°. Następnie wykonano testy progresywnego niszczenia próbek w warunkach dynamicznych z zastosowaniem młota opadowego oraz dodatkowego elementu - inicjatora. Wprowadzono nowy współczynnik do opisu udziału masowego włókien osiowych. Obliczono wartości zaabsorbowanej energii (SEA), które wskazują, że im większy udział włókien osiowych, tym większa ilość zaabsorbowanej energii dla obu typów próbek, oraz wskazano na prawdopodobne występowanie efektu skali.