Formulae for the Impedance and Transmission Factor of an Electrically Small Half-Sheath Dipole Antenna Immersed in Seawater

Abstrak - Antena merupakan alat pemancar yang akrab dengan aktifitas sehari-hari dan mudah sekali dijumpai, di rumah, di gedung, bahkan pada alat komunikasi yang digunakan. Salah satu antena yang sering digunakan adalah antena televisi. Antena televisi yang sering digunakan adalah Yagi-Uda yang biasanya dipakai sebagai outdoor antena dan antena dipole yang biasanya digunakan untuk indoor antena. Masing – masing jenis antena memiliki kriteria dan keuntungan berdasarkan dari kebutuhan penggunaannya. Baik antena dipole maupun antena Yagi-Uda memiliki perbedaan diantaranya adalah besar bandwidth, nilai gain, dan pola radiasi. Pada paper ini dapat diketahui bahwa bandwidth yang dimiliki antena yagi-uda lebih besar daripada antena dipole yakni 0.39943 MHz untuk antena yagi-uda dan 0.16569 MHz untuk antena dipole. Begitupula dengan besar Gain yang dimiliki antena Yagi-Uda (6.64 dBi) lebih besar dibandingkan dengan gain dari antena dipole (2.29 dBi). Perbedaan ini dikarenakan faktor elemen director dan ketebalannya. Kata Kunci – Atena Televisi, Atena Yagi-Uda, Atena Dipole, Gain, Bandwidth Abstract - Antenna is a transmitter tool that is familiar with daily activity and easy to find at home, in the building, even on the communication tool used. One of antenna that is often used is a television antenna. Television antennas are often used is Yagi-Uda which is usually used as an outdoor antenna and dipole antenna that is usually used for indoor antennas. Each type of antenna has the criteria and advantages based on the needs of its use. Both dipole antennas and Yagi-Uda antennas have differences among them are bandwidth, gain, and radiation pattern. In this paper it can be seen that the bandwidth of yagi-uda antenna is bigger than dipole antenna that is 0.39943 MHz for Yagi-Uda antenna and 0.16569 MHz for dipole antenna. Neither the large Gain of the Yagi-Uda antenna (6.64 dBi) is greater than the gain of the dipole antenna (2.29 dBi). This difference is due to element factor of director and its thickness. Keywords – Television Antenna, Yagi-Uda Antenna, Dipole Antenna, Gain, Bandwidth

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Radiation characteristics of a wide-band dipole antenna over an electromagnetic band-gap reflector

2014 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC) ◽

10.1109/apwc.2014.6905559 ◽

2014 ◽

Cited By ~ 1

Author(s):

M. Tanabe ◽

Y. Oishi ◽

Y. Masuda

Keyword(s):

Band Gap ◽

Wide Band ◽

Dipole Antenna ◽

Radiation Characteristics ◽

Electromagnetic Band Gap

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The Role of La2O3 in Enhancement the Radiation Shielding Efficiency of the Tellurite Glasses: Monte-Carlo Simulation and Theoretical Study

Materials ◽

10.3390/ma14143913 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3913

Author(s):

Aljawhara H. Almuqrin ◽

Mohamed Hanfi ◽

K. G. Mahmoud ◽

M. I. Sayyed ◽

Hanan Al-Ghamdi ◽

...

Keyword(s):

Monte Carlo Simulation ◽

Theoretical Study ◽

Radiation Shielding ◽

Photon Flux ◽

Transmission Factor ◽

Tellurite Glasses ◽

Attenuation Coefficients ◽

Binary Glass ◽

Buildup Factors

The radiation shielding competence was examined for a binary glass system xLa2O3 + (1 − x) TeO2 where x = 5, 7, 10, 15, and 20 mol% using MCNP-5 code. The linear attenuation coefficients (LACs) of the glasses were evaluated, and it was found that LT20 glass has the greatest LAC, while LT5 had the least LAC. The transmission factor (TF) of the glasses was evaluated against thicknesses at various selected energies and was observed to greatly decrease with increasing thickness; for example, at 1.332 MeV, the TF of the LT5 glass decreased from 0.76 to 0.25 as the thickness increased from 1 to 5 cm. The equivalent atomic number (Zeq) of the glasses gradually increased with increasing photon energy above 0.1 MeV, with the maximum values observed at around 1 MeV. The buildup factors were determined to evaluate the accumulation of photon flux, and it was found that the maximum values for both can be seen at around 0.8 MeV. This research concluded that LT20 has the greatest potential in radiation shielding applications out of the investigated glasses due to the glass having the most desirable parameters.

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Design of Wideband Filtering Magnetoelectric Dipole Antenna with a Flat Gain utilizing U-shaped Slot

2020 International Conference on Microwave and Millimeter Wave Technology (ICMMT) ◽

10.1109/icmmt49418.2020.9387033 ◽

2020 ◽

Author(s):

Guorong Tang ◽

Zhaohui Wei ◽

Huidong Li ◽

Xiaoyu Du ◽

Jian Ren ◽

...

Keyword(s):

Dipole Antenna ◽

Flat Gain

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Enhancement of the Shielding Capability of Soda–Lime Glasses with Sb2O3 Dopant: A Potential Material for Radiation Safety in Nuclear Installations

Applied Sciences ◽

10.3390/app11010326 ◽

2020 ◽

Vol 11 (1) ◽

pp. 326

Author(s):

M.I. Sayyed ◽

K.A. Mahmoud ◽

O.L. Tashlykov ◽

Mayeen Uddin Khandaker ◽

M.R.I. Faruque

Keyword(s):

Attenuation Coefficient ◽

Elastic Moduli ◽

Gamma Ray ◽

Radiation Safety ◽

Soda Lime ◽

Mass Attenuation Coefficient ◽

Transmission Factor ◽

Linear Attenuation Coefficient ◽

Neutron Shielding ◽

Removal Cross Section

Elastic moduli were theoretically computed using the Makishima–Mackenzie model for SiO2–Na2O–CaO glasses doped with Sb2O3 contents. The calculated elastic moduli (Young’s, bulk, shear, and longitudinal modulus) were observed to increase with an increase in the Sb2O3 contents. The microhardness showed an increase, while Poisson’s ratio decreased with the rise of the Sb2O3 contents. In addition, gamma-ray and neutron shielding parameters were evaluated for the investigated glasses. The linear attenuation coefficient (LAC) was simulated using the Monte Carlo N-particle transport code (MCNP-5). Other parameters, such as the mass attenuation coefficient (MAC), transmission factor (TF), and half-value layer, were calculated based on the simulated LAC. The addition of Sb2O3 content was observed to enhance the investigated glasses’ shielding parameters, where the highest LAC was achieved for the SCNSb10 glass with 10 mol% Sb2O3 and decreased from 0.441 to 0.154 cm−1 at gamma energies between 0.248 and 1.406 MeV. Furthermore, the fast neutron effective removal cross-section (∑R) was computed theoretically. The calculated results showed that the highest ∑R was equal to 0.0341 cm2g−1 and was obtained for the SCNSb0 glass, which had no Sb2O3 content, while the lowest ∑R was equal to 0.0286 cm2 g−1 for the SCNSb10 glass sample. The present work was carried out to examine the advantages of the soda–lime glasses with different Sb2O3 contents in several photon shielding applications, especially for radiation safety in nuclear installations.

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