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1

Dual Frequency Triangular Slotted Microstrip Patch Antenna for Ku Band Applications

Samsuzzaman M., Islam M. T., Yatim B., Ali M. A.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 1a

275--279

EN

A single feed, compact, new shaped, dual band microstrip patch antenna has presented in this paper. Here three equilateral triangular slots are introduced in the three edges of the patch and a small feed line has used another edge of the patch to obtain the dual band. The antenna has a condensed structure where patch dimension is about 8.5mm by 7.96mm by 1.905mm leading to good bandwidths covering 13.15 GHz to 13.72 GHz and 16.04 GHz to 16.58GHz. The return loss of -19.00dB is achieved at the first resonant frequency at 13.61 GHz and -28.69dB is at second resonance frequency at 16.33GHz. Stable average peak gain that is observed across the operating band in both lower and higher frequency is almost 3.53dB and 5.562dB respectively .The radiation patterns are nearly omnidirectional with moderate gain in both these operating bands. Good results have been established in dual frequencies at 13.62GHz as downlink and 16.33GHz as uplink. This low profile nature and simple configuration of the proposed antenna show the way to easy fabrication and make it adaptable for the application in wireless and satellite communication.

PL

W artykule przedstawiono dwupasmową prostokątną antenę mikropaskową o jednym doprowadzeniu i nowym kształcie. W trzech rogach znajdują się trzy szczeliny w kształcie trójkąta równobocznego, a w czwartym doprowadzenie linii. Antena posiada pasmo 13,15-13,72GHz oraz 16,04-16,58GHz. Niski profil oraz prosta konfiguracja wskazują na łatwą metodę produkcji oraz możliwość zastosowania w aplikacjach bezprzewodowych i komunikacji satelitarnej.

2

Compact Dual Band RFID Reader Antenna Designed using Ramped Convergence Particle Swarm Optimization

Kibria S., Islam M.T., Yatim B.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 4

199-201

EN

A simple Particle Swarm Optimization (PSO) variant for micro-strip antennae is presented in this paper. A dual-band RFID reader broadband antenna, designed through traditional means, is optimized using this Ramped Convergence PSO (RCPSO). It is a Multi-Start algorithm that works on a specific set of optimization parameters. The algorithm is implemented using Matlab for the RCPSO computations. It uses Zeland IE3D 10.3 for simulation and fitness evaluation. The gain improves a significant 2 dBi over SHF band while keeping the effective antenna size same.

PL

W artykule przedstawiono zastosowanie wariantu algorytmu PSO (RCPSO - PSO z konwergencją zmienną wg. rampy) w optymalizacji anteny mikro-paskowej typu RFID (dwupasmowa). Algorytm, ze względu na swoją specyfikację, wymaga dopasowania parametrów optymalizacji. Całość zaimplementowana została w Matlabie. W symulacjach oraz ocenie sprawności wykorzystywane jest środowisko Zeland IE3D 10.3.

3

The response of TEC at quasi-conjugate point GPS stations during solar flares

Bahari S.A., Abdullah M., Yatim B.

Acta Geophysica

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2011

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Vol. 59, no. 2

407-427

EN

Global Positioning System (GPS) derived total electron content (TEC) measurements were analyzed to investigate the ionospheric response during the X-class solar flare event that occurred on 5-6 December 2006 at geomagnetic conjugate stations: Syowa, Antarctica (SYOG) (GC: 69.00° S, 39.58° E; CGM: 66.08° S, 71.65° E) and Árholt, Iceland (ARHO) (GC: 66.19° N, 342.89° E; CGM: 66.37° N, 71.48° E). Bernese GPS software was used to derive the TEC maps for both stations. The focus of this study is to determine the symmetry or asymmetry of TEC values which is an important parameter in the ionosphere at conjugate stations during these solar flare events. The results showed that during the first flares on 5 December, effects were more pronounced at SYOG than at ARHO. However, on 6 December, the TEC at ARHO showed a sudden spike during the flare with a different TEC variation at SYOG.

4

Solar forcing on antarctic terrestrial climate: a study by means of GPS observations

Suparta W., Yatim B., Mohd Ali M.A.

Acta Geophysica

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2010

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Vol. 58, no. 2

374-391

EN

With a view to difficulties with explaining the physical mechanism of solar forcing on the Earth’s climate, we applied a new approach of determining and quantifying an influence of solar-related events on water vapor variability by correlating the total electron content (TEC) and precipitable water vapor (PWV), both derived from ground-based GPS observations. In this study, ionospheric TEC and atmospheric PWV values are employed as solar activity and terrestrial climate parameters, respectively. Three-year GPS data at five stations in Antarctica are analyzed on a daily mean basis. Results show significant correlation between TEC and PWV differences during storms-affected days. The high correlation between the daily mean values of TEC and PWV, both of which follow the seasonal signals and subsisting downward trend, suggests an influence of solar activity on climate variability in Antarctica. These quantities are determined by changes of the upper-atmosphere level, which varies in conformity with the zenith angle of the Sun.

5

GPS observations at quasi-conjugate points under disturbed conditions

Momani M.A., Mohd Ali M.A., Yatim B., Abdullah M., Misran N.

Acta Geophysica

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2008

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Vol. 56, no. 4

1179-1201

EN

The conjugacy effects of the GPS scintillation activities during the geomagnetic storms of October 2003, November 2003 and July 2004 have been investigated at the approximately geomagnetically conjugate stations: Scott Base, Antarctica (SBA) and Resolute Cornwallis Island (RESO) in the high Arctic region. The measurements aim at investigation of the similarities and differences of the scintillation activities occurring at the conjugate points in the polar regions under storm conditions and examine the relationship between the Storm Enhanced Density (SED) and scintillation activity. The measurements of the scintillation activities obtained from total scintillation index during these storm periods at both hemispheres showed asymmetry in the ionospheric scintillation occurrence at the conjugate points. Pronounced scintillation activity was observed at the nightside hemisphere with the total scintillation index higher than at the dayside hemisphere. The results also show that the durations of severe scintillation activity were longer at the nightside hemisphere. The measurements showed that the intense scintillation periods were corresponding to the presence of the SED events where more pronounced SED events were observed over the nightside hemisphere.