نتایج جستجو برای: gsm radiation
تعداد نتایج: 242554 فیلتر نتایج به سال:
The design of a novel Fractal planar inverted F antenna (F-PIFA) based on the self affinity property is presented in this paper. The procedure for designing a Fractal Planar Inverted F Antenna is explained and three different iterations are designed for use in cellular phones. The F-PIFA has a total dimension of 27mm× 27mm and has been optimized to be operational at GSM (Global System for Mobil...
A dual-band multiple-input-multiple-output (MIMO) antenna system for LTE 700/2300/2500, UMTS2100, GSM 1800/1900 mobile phone applications is presented. The whole system consists of four identical 3-D IFAs (inverted F antenna) loaded with lumped inductors and folded on FR4 cuboids. Without any special designed decoupling structures, the measured isolation among antenna elements is higher than 13...
سابقه و هدف: اغلب افراد جامعه به طور ناخواسته تحت تاثیر امواج تولیدی از آنتن های گیرنده/ فرستنده تلفن همراه هستند. این مطالعه in vivo به منظور بررسی نتایج حاصل از تابش امواج 950 مگاهرتز سیستم تلفن هم راه gsm بر تقویت طولانی مدت (long-term potentiation, ltp) ناحیه dentate gyrus صورت گرفت. مواد و روش ها: 32 راس موش بزرگ آزمایشگاهی مذکر از نژاد ویستار با سنی حدود 3 ماه و وزن 15±220 گرم، به طور تصا...
In this paper, a simple dual-band dual-polarized aperture stacked patch antenna with double sided notch is presented. This antenna is suitable for operation in telecommunication base stations. One of the bands covers the GSM band, while the other covers both DCS and UMTS bands. The proposed antenna shows good port decoupling of less than -30dB for dual linear polarization over its operating ban...
در این مقاله، یک مقسم توان ویلکینسون سه بانده‌ی مایکرواستریپی، با استفاده از سه بخش سری شده‌ی معادل به جای خط انتقال ربع طول موج متداول، طراحی و شبیه‌سازی شده است. ساختار پیشنهادی دارای قابلیت گزینش‌گری بالا برای طراحی ابعاد می‌باشد. در همین راستا، با استفاده از الگوریتم PSO، انتخاب‌های بهینه برای طول‌های الکتریکی سه بخش سری شده‌ی معادل، امپدانس‌های مشخصه‌ی نظیر خطوط و در نهایت، طراحی سه مقاومت...
In the course of modern daily life, individuals are exposed to numerous sources of electromagnetic radiation that are not present in the natural environment. The strength of the electromagnetic fields from sources such as hairdryers, computer display units and other electrical devices is modest. However, in many home and office environments, individuals can experience perpetual exposure to an "...
The Stockholm Central Railway Station in Sweden was investigated for public radiofrequency (RF) radiation exposure. The exposimeter EME Spy 200 was used to collect the RF exposure data across the railway station. The exposimeter covers 20 different radiofrequency bands from 88 to 5,850 MHz. In total 1,669 data points were recorded. The median value for total exposure was 921 µW/m2 (or 0.092 µW/...
Background: The rapidly increasing use of mobile phones has led to public concerns about possible health effects of these popular communication devices. This study is an attempt to investigate the effects of radiofrequency (RF) radiation produced by GSM mobile phones on the insulin release in rats.Methods: Forty two female adult Sprague Dawley rats were randomly divided into 4 groups. Group1 we...
A number of serious non thermal biological effects, ranging from changes in cellular function like proliferation rate changes or gene expression changes to cell death induction, decrease in the rate of melatonin production and changes in electroencephalogram patterns in humans, population declinations of birds and insects, and small but statistically significant increases of certain types of ca...
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