Transmission line approach of zero-index metamaterials and applications using a wave concept iterative method

2019 ◽  
Vol 11 (3) ◽  
pp. 244-254
Author(s):  
Mohamed Karim Azizi ◽  
Taieb Elbellili ◽  
Henri Baudrand ◽  
Hichem Trabelsi

AbstractIn this paper, we propose a novel study of zero-index materials (ZIM) based on lumped element circuits using a wave concept iterative method (WCIP). This method is well used to demonstrate the behavior of zero-index-based microwave applications. This type of metamaterial can maintain the amplitude and the phase of an electromagnetic wave to be constant through the ZIM region, which is an important property to design an in-phase power divider-combiner, enhance the directivity of an embedded source, channel electromagnetic waves without reflection at the interface between waveguides with different cross-sections, and control the transmission of electromagnetic wave by the adjustment of the permittivity of a dielectric defect coated by zero-index metamaterial. The numerical simulations using the WCIP method match the literature and commercial software simulator results.

2019 ◽  
Vol 3 (1) ◽  
pp. 1-7
Author(s):  
Ummu Aiman ◽  
Nirwana Nirwana ◽  
M Lutfi Firdaus

Abstract[Improvement of students learning outcomes by applying the video of coffee-mixture identification using UV-Visible Spectroscopy]. The purpose of this study was to evaluate the differences of student learning outcomes on electromagnetic wave materials and how students respond to the learning videos. This research was an experimental research which applies video coffee-mixture identification. The study was conducted in grade X islamic high school consisting of experimental class and control class. Based on the data analysis, the average post-test grade of the experimental class was 82.11 and the mean post-test control grade was 72.88 with tcount = 0,038 which is lower than the value of significance (0,05). The N-gain values of both classes indicate that the experimental class (0.72) is better than the control class (0.61). This suggests the adoption of a coffee-mixture identification video on electromagnetic wave material able to improve greater learning outcomes than control class that did not apply the video to the learning process. The result of questionnaire analysis shows that the student response to video implementation is good, as seen from the average score of responses of students who answered strongly agree at 40% level, while the answer agree at 53.83% level, not agree at 5.43% level and who answered very disagreeing 0.74% of all students. Keywords: Coffee-mixture; UV-Visible spectroscopy; electromagnetic waves; learning video.(Received August 15 2018; Accepted January 25, 2019; Published February 25, 2019) AbstrakPenelitian ini dilakukan dengan tujuan untuk menjelaskan perbedaan peningkatan hasil belajar siswa pada materi gelombang elektromagnetik dan bagaimana respon siswa terhadap video pembelajaran. Penelitian ini merupakan penelitian eksperimen yang menerapkan video identifikasi campuran kopi. Penelitian dilaksanakan di Madrasah Aliyah kelas X yang terdiri dari kelas eksperimen dan kelas kontrol. Berdasarkan hasil analisis data, rata-rata nilai post-test kelas eksperimen adalah 82,11 dan rata-rata nilai post-test kelas kontrol 72,88 dengan nilai thitung = 0,038 < nilai signifikansi (0,05). Adapun nilai N-gain dari kedua kelas menunjukkan bahwa pada kelas eksperimen  (0,72) lebih baik dari  pada kelas kontrol (0,61). Hal ini menunjukkan bahwa penerapan video identifikasi campuran kopi pada materi gelombang elektromagnetik dapat meningkatkan hasil belajar yang lebih besar dibandingkan kelas kontrol yang tidak menerapkan video pada proses pembelajarannya. Sedangkan hasil analisis angket diketahui bahwa respon siswa terhadap penerapan video adalah baik, terlihat dari nilai rata-rata respon siswa yang menjawab sangat setuju sebesar 40%, sedangkan yang menjawab setuju sebesar 53,83%, tidak setuju sebesar 5,43% dan  yang menjawab sangat tidak setuju sebesar 0,74% dari keseluruhan siswa. Kata kunci: Campuran kopi; spektroskopi UV-Vis; gelombang elekromagnetik; video pembelajaran


2019 ◽  
Vol 3 (1) ◽  
pp. 1-7
Author(s):  
Ummu Aiman ◽  
Nirwana Nirwana ◽  
M Lutfi Firdaus

Abstract[Improvement of students learning outcomes by applying the video of coffee-mixture identification using UV-Visible Spectroscopy]. The purpose of this study was to evaluate the differences of student learning outcomes on electromagnetic wave materials and how students respond to the learning videos. This research was an experimental research which applies video coffee-mixture identification. The study was conducted in grade X islamic high school consisting of experimental class and control class. Based on the data analysis, the average post-test grade of the experimental class was 82.11 and the mean post-test control grade was 72.88 with tcount = 0,038 which is lower than the value of significance (0,05). The N-gain values of both classes indicate that the experimental class (0.72) is better than the control class (0.61). This suggests the adoption of a coffee-mixture identification video on electromagnetic wave material able to improve greater learning outcomes than control class that did not apply the video to the learning process. The result of questionnaire analysis shows that the student response to video implementation is good, as seen from the average score of responses of students who answered strongly agree at 40% level, while the answer agree at 53.83% level, not agree at 5.43% level and who answered very disagreeing 0.74% of all students. Keywords: Coffee-mixture; UV-Visible spectroscopy; electromagnetic waves; learning video.(Received August 15 2018; Accepted January 25, 2019; Published February 25, 2019) AbstrakPenelitian ini dilakukan dengan tujuan untuk menjelaskan perbedaan peningkatan hasil belajar siswa pada materi gelombang elektromagnetik dan bagaimana respon siswa terhadap video pembelajaran. Penelitian ini merupakan penelitian eksperimen yang menerapkan video identifikasi campuran kopi. Penelitian dilaksanakan di Madrasah Aliyah kelas X yang terdiri dari kelas eksperimen dan kelas kontrol. Berdasarkan hasil analisis data, rata-rata nilai post-test kelas eksperimen adalah 82,11 dan rata-rata nilai post-test kelas kontrol 72,88 dengan nilai thitung = 0,038 < nilai signifikansi (0,05). Adapun nilai N-gain dari kedua kelas menunjukkan bahwa pada kelas eksperimen  (0,72) lebih baik dari  pada kelas kontrol (0,61). Hal ini menunjukkan bahwa penerapan video identifikasi campuran kopi pada materi gelombang elektromagnetik dapat meningkatkan hasil belajar yang lebih besar dibandingkan kelas kontrol yang tidak menerapkan video pada proses pembelajarannya. Sedangkan hasil analisis angket diketahui bahwa respon siswa terhadap penerapan video adalah baik, terlihat dari nilai rata-rata respon siswa yang menjawab sangat setuju sebesar 40%, sedangkan yang menjawab setuju sebesar 53,83%, tidak setuju sebesar 5,43% dan  yang menjawab sangat tidak setuju sebesar 0,74% dari keseluruhan siswa. Kata kunci: Campuran kopi; spektroskopi UV-Vis; gelombang elekromagnetik; video pembelajaran


2014 ◽  
Vol 5 (2) ◽  
pp. 151-156
Author(s):  
Z. Mechbal ◽  
A. Khamlichi

Composites made from E-glass/epoxy or aramid/epoxy are frequently used in aircraft and aerospace industries. These materials are prone to suffer from the presence of delamination, which can reduce severely the performance of aircrafts and even threaten their safety. Since electric conductivity of these composites is rather small, they can propagate electromagnetic waves. Detection of delamination damage can then be monitored by using an electromagnetic penetrating radar scanner, which consists of emitting waves having the form of short time pulses that are centered on a given work frequency. While propagating, these waves undergo partial reflection when running into an obstacle or a material discontinuity. Habitually, the radar is moved at constant speed along a straight path and the reflected signal is processed as a radargram that gives the reflected energy as function of the two-way time and the antenna position.In this work, modeling of electromagnetic wave propagation in composites made from E-glass/epoxy was performed analytically. The electromagnetic wave reflection from a delamination defect was analyzed as function of key intervening factors which include the defect extent and depth, as well as the work frequency. Various simulations were performed and the obtained results have enabled to correlate the reflection pattern image features to the actual delamination defect characteristics which can provide quantification of delamination.


1998 ◽  
Vol 63 (8) ◽  
pp. 1187-1201 ◽  
Author(s):  
Jaroslav Zamastil ◽  
Lubomír Skála ◽  
Petr Pančoška ◽  
Oldřich Bílek

Using the semiclassical approach for the description of the propagation of the electromagnetic waves in optically active isotropic media we derive a new formula for the circular dichroism parameter. The theory is based on the idea of the time damped electromagnetic wave interacting with the molecules of the sample. In this theory, the Lambert-Beer law need not be taken as an empirical law, however, it follows naturally from the requirement that the electromagnetic wave obeys the Maxwell equations.


2020 ◽  
Vol 9 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Shumin Du ◽  
Huaiyin Chen ◽  
Ruoyu Hong

AbstractWith the rapid development of electronics and information technology, electronics and electrical equipment have been widely used in our daily lives. The living environment is full of electromagnetic waves of various frequencies and energy. Electromagnetic wave radiation has evolved into a new type of environmental pollution that has been listed by the WHO (World Health Organization) as the fourth largest source of environmental pollution after water, atmosphere, and noise. Studies have shown that when electromagnetic wave radiation is too much, it can cause neurological disorders. And electromagnetic interference will cause the abnormal operation of medical equipment, precision instruments and other equipment, and therefore cause incalculable consequences. Therefore, electromagnetic protection has become a hot issue of concern to the social and scientific circles.


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