A Broadband Electromagnetic Absorber for Mobile Telecommunication Combo Antennas

Yıl 2019, Cilt: 2 Sayı: 1, 46 - 54, 16.06.2019

Niyazi Uluaydın Şaban Selim Şeker

Öz

Mobile
network operators (MNOs) have to sustain the interworking of different
generations of mobile technologies in different frequency bands.  On the other hand, electromagnetic (EM)
pollution, which is caused mainly by the mobile devices and mobile network base
stations, also raises public health concerns. Thus, MNOs use combo antennas,
which encapsulate multiple antenna rods in a single radome. In this study, the
authors propose a broadband electromagnetic absorber for the mobile network
base station (BS) combo antennas. They have merged the multi-layer Jaumann
absorber (JA) and Salisbury screen principles along with the merits of
off-the-shelf micrometric and millimetric graphite and nanometric carbon black.
Advanced silver and nickel coated nanometric cenospheres were also used to
decrease the absorber thickness and to improve EM scattering and absorption.
And finally, silver fabric was used as the salisbury screen with novel
perpendicular threads into the absorber body as heat sink.   After the laboratory tests, the absorber has
also been tested in the field. The application of the absorber has reduced the
unwanted radio frequency (RF) signal around 18 dB in the tested frequency range
without any network affecting disturbances or without any noticeable antenna
pattern deformation with only a thickness of ninety millimeters. Such an
absorber may also help containing the unwanted spread of electromagnetic waves
from BS antennas; and, in return, decrease the overall mobile network RF noise
and electromagnetic pollution both in uplink and downlink frequency bands.

Anahtar Kelimeler

5G, 4G, 3G, Electromagnetic Wave Absorption, Base Station, Mobile Telecommunication

Mobil Haberleşme Combo Antenleri için Genişband Elektromanyetik Sönümlendirici

Öz

Mobil Şebeke İşletmecileri (MŞİ) farklı jenerasyon mobil teknolojilerinin farklı sıklık aralıklarında düzgün çalışmasını sağlamak zorundadırlar. Öte yandan, elektromanyetik (EM) kirlilik, ki daha çok mobil telefonlar ve mobil baz istasyonları tarafından kaynaklanır, toplumda sağlık kaygıları yaratmaktadır. Bu sebeple, MŞİler birçok anten çubuğunu tek bir radomeda saklayan combo antenleri kullanmaktadırlar. Bu çalışmada, araştırmacılar mobil şebeke baz istasyonu combo antenleri için genişband bir elektromanyetik sönümlendirici önermektedirler. Araştırmacılar bunun için çok katmanlı Jaumann sönümlendirme (JS) ve Salisbury ekranlama prensiplerini mikrometrik ve milimetrik grafit ve nonametrik karbon siyahı malzemeleri üzerine uygulamıştır. Buna ek olarak, ileri teknoloji gümüş ve nikel kaplanmış seramik kürecikler de sönümlendirici kalınlığını azaltmak üzere EM saçılımını arttırmak ve sönümlenmeyi iyileştirmek için kullanılmıştır. Son olarak, gümüş kaplı naylon kumaş da salisbury ekranlamasının en yenilikçi şekli ile sönümlendiriciye dik iplikçiklerle yerleştirilerek ısınma sorununu çözmüştür. Laboratuvar testlerinden sonra, sönümlendirici sahada test edilmiştir.  Doksan milimetre kalınlığındaki bir sönümlendirici uygulaması istenmeyen radyo frekans (RF) sinyalini mobil şebekenin çalışmasını engellemeden ve anten yayınım şeklini değiştirmeden 18 dB azalmiştir. Bu tip bir sönümlendirici istenmeyen elektromanyetik dalgaların yayılmasını engellemeye yardımcı olabilir ve bütün mobil şebeke RF gürültüsünü ve EM kirliliğini her iki yayın yönünde de azaltabilir. 

Anahtar Kelimeler

5J, 4J, 3J, Elektromanyetik Dalga Sönümleme, Baz İstasyonu, Mobil Haberleşme

Kaynakça

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