Showing papers in "Informacije Midem-journal of Microelectronics Electronic Components and Materials in 2011"

Dual polarized microstrip patch antenna for Ku-band application

Abstract: A dual polarized microstrip patch antenna is proposed for Ku-band applications. The corner chopped square patch with four bent slots is adopted in this design. The antenna has a compact structure and the total size is 15 mm × 15 mm. The result shows that the impedance bandwidth (VSWR ≤ 2) of the proposed antenna is 950 MHz (7.76%). The antenna with reduced size is also able to achieve the stable radiation performance with a maximum gain of 7.6 dBi in the operating band of 11.76 GHz to 12.71 GHz and the gain variation is about 0.8 dBi. The present design provides a maximum of -26 dB isolation level between the two ports and a stable low cross polarization level for both Eand H-planes. Details of the proposed antenna design and results are presented and discussed. The patch shows a high matching level in Ku-band and isolation elements that makes it suitable for wireless and satellite communication. Dvojno polarizirana mikrostrip antena za Ku-frekvenčni pas Kjučne besede: dvojna polarizacija, mikrotrakasta antena, Ku-frekvenčni pas, visoka izolacija Izvleček: V prispevku opišemo mikrotrakasto anteno z dvojno polarizacijo za uporabo na Ku-frekvenčnem pasu. Antena ima kompaktno strukturo in je velika 15 mm x 15 mm. Rezultati kažejo pasovno širino ( VSWR ≤ 2) 950 MHz (7.76%). Tako zmanjšana antena zmore stabilno sevanje z maksimalno ojačitvijo 7.6 dBi znotraj pasovne širine med 11.76 GHz do 12.71 GHz in stabilnostjo ojačitve znotraj 0.8 dBi. Trenutna zasnova omogoča maksimalno izolacijo med stopnjama -26dB in stabilno nizko križno polarizacijo med E in H ravnijo. V članku so opisane podrobnosti in rezultati predlagane zasnove antene.

Compact UWB planar antenna for broadband applications

Abstract: In this paper, a planar antenna for broadband applications has been proposed. The antenna consists of a rectangular patch, a partial ground plane and a slot on the ground plane. The proposed antenna is easy to be integrated with microwave circuitry for low manufacturing cost. The flat type antenna has a compact structure and the total size is 14.75 ×14.5mm. The result shows that the impedance bandwidth (VSWR ≤ 2) of the proposed antenna is 12.87 GHz (3.02 to 15.89 GHz), which is equivalent to 136.12%. Details of the proposed compact planar UWB antenna design is presented and discussed.

Influence of SAR reduction in muscle cube with metamaterial attachment

Abstract: The purpose of this paper is to calculate the specific absorption rate (SAR) reduction in muscle cube with metamaterial attachment. The finitedifference time-domain (FDTD) method has been used to evaluate the SAR in a realistic anatomically based model of the muscle cube. We design the single negative metamaterials from periodic arrangement of split ring resonators (SRRS). By properly designing structural parameter of SRRS, the effective medium parameter can be trade negative at 900 MHz and 1800 MHz band in this paper. Numerical results of SAR values in muscle cube with presence of resonators exhibit SAR reduction. These results can provide useful information in designing safety mobile communication equipment compliance. Zmanjšanje SAR v modelu mišične kocke z dodatkom metamateriala Kjučne besede: SAR, zmanjšanje SAR, mišična kocka, dodatek metamateriala, mobilne komunikacijske naprave Izvleček: Namen članka je izračunati zmanjšanje specifične stopnje absorpcije (SAR) v mišični kocki z dodatkom metamateriala. Za ocenjevanje SAR v realnem anatomskem modelu mišične kocke je bila uporabljena FDTD ( finite-difference time-domain ) metoda. Model metamaterialov smo izdelali s pomočjo periodične structure resonatorjev tipa SRRS ( SRRS – split-ring resonator ) Z ustrezno izbiro strukturnih parametrov SRRS lahko dosežemo negativno prepustnost pri frekvencah 900 MHz in 1800 MHz. Numerični rezultati SAR vrednosti v mišični kocki ob prisotnosti resonatorjev SRRS kažejo na zmanjšanje SAR. Rezultati so tako uporaben vir informacij pri načrtovanju varnih mobilnih komunikacijskih naprav.

CVL OCR DB, an annotated image database of text in natural scenes, and its usability

Abstract: Text detection and optical character recognition (OCR) in images of natural scenes is a fairly new computer vision area but yet very useful in numerous applicative areas. Although many implementations gain promising results, they are evaluated mostly on the private image collections that are very hard or even impossible to get. Therefore, it is very difficult to compare them objectively. Since our aim is to help the research community in standardizing the evaluation of the text detection and OCR methods, we present CVL OCR DB, a public database of annotated images of text in diverse natural scenes, captured at varying weather and lighting conditions. All the images in the database are annotated with the text region and single character location informa- tion, making CVL OCR DB suitable for testing and evaluating both text detection and OCR methods. Moreover, all the single characters are also cropped from the original images and stored individually, turning our database into a huge collection of characters suitable for training and testing OCR classifiers.

Design and development of compact microstrip antennas for portable device applications

Abstract: During the last decade, wireless communication system developments have been a major motivator of compact antenna research, most particularly for portable device applications. This paper addresses to a development procedure of designing compact antennas. By a careful observation at the current distribution and folding of slots after calculating the resonating slot length, the compactness of microstrip antenna can be achieved. Two compact slot antennas, namely hollow central annular slot antenna (HCASA) and spiral slot antenna (SSA) are designed and prototyped for validation, where the experimental result agrees well the simulation. The overall volume of these antennas are respectively 0.11λ×0.11λ×0. 005λ and 0.08λ×0. 08λ×0.005λ where λ× is the free space operating wavelength, that concludes the reduction of 75 and 86.2% of antenna volume comparing that of an ordinary annular slot antenna operating at the same frequency.

Ultra-compact wideband antenna for portable device applications

Abstract: An ultra-compact broadband antenna easily integrable on portable devices is presented. The antenna is composed of a printed rectangular radiating element and a C-strip printed as the ground plane on the other side. The overall antenna occupies a compact area of 56.5 × 2 × 0.5 mm , yet generating two resonant modes to form 39% (850MHz) wide impedance bandwidth from 1.75 to 2.6GHz with stable omni-directional radiation pattern with low cross-polarization.

Analysis of metamaterial attachment for em absorption in human head

Abstract: The reducing specific absorption rate (SAR) with metamaterials attachment is investigated in this paper. The finite-difference time-domain method with lossy-Drude model is adopted in this analysis. The technique of SAR reduction is discussed and the effects of attaching location, distance, and size of metamaterials, perfect electric conductor (PEC), and materials on the SAR reduction are investigated. Metamaterials have achieved a 41.47% reduction of the initial SAR value for the case of 1 gm SAR. These results suggest a guideline to choose various types of metamaterials with the maximum SAR reducing effect for a phone model. Vpliv dodatka metamateriala na absorpcijo EM valovanja v cloveski glavi Kjucne besede: antena, model cloveske glave, lossy-Drude model, metamateriali, specificna absorbcijska stopnja (SAR) Izvlecek: v clanku opisemo zmanjsanje parametra SAR ( specificna absorbcijska stopnja ) z dodatkom metamateriala. Analizo smo opravili z modelom Drude in uporabo koncnih diferenc v casovni domeni. Opisana je tehnika zmanjsanja parametra SAR , raziskani so vpliv lokacije, oddaljenosti in velikosti metamaterialov ter vpliv popolnega elektricnega prevodnika (PEC) in vrste metamaterialov na zmanjsanje SAR. Z uporabo metamaterialov smo dosegli 41,47 % zmanjsanje zacetne vrednosti SAR, ki je bila 1gm SAR. Ti rezultati pomenijo neko vrsto smernic za izbiro materialov za mobilne telefone, ki najbolj zmanjsujejo parameter SAR.

Influence of material attachment for EM absorption

Abstract: In this paper, reducing electromagnetic absorption (EM) with materials attachment is investigated. The finite-difference time-domain method with lossy-Drude model is adopted in this study. The methodology of SAR reduction is addressed and the effects of attaching location, distance, and size of ferrite sheet material on the SAR reduction are investigated. Materials have achieved a 47.68% reduction of the initial SAR value for the case of 1 gm SAR. These results suggest a guideline to choose various types of materials with the maximum SAR reducing effect for a phone model. Vpliv feritnega dodatka na EM absorpcijo Kjučne besede: antena, človeški model glave, model lossy-Drude, materiali, SAR Izvleček: v članku raziskujemo vpliv dodatnih pritrjenih materialov na EM absorpcijo. Pri simulaciji smo uporabili dva modela. S pomočjo metodologije SAR zasledujemo vpliv položaja, razdalje in velikosti ploskih feritnih materialov na zmanjševanje SAR. Dodani materiali zmanjšajo za 47.68 % začetno SAR vrednost v primeru 1g SAR. S pomočjo teh rezultatov pridemo do smernic pri izbiri materialov za doseganje največjega SAR zmanjšanja za model telefona.

Temporal modeling of human activity in smart homes

Abstract: Recognition of human activity is a potential challenge to design an effective smart home. The paper proposed a novel algorithm to recognize activities of daily living (ADL) of the resident. It provides analysis and mathematical modeling of temporal intervals of the event. The opposite entity states are used to extract the pattern of event sequence. Each extracted episode represents a distinct task of the resident. Result shows that, the algorithm can successfully identify 135 unique tasks of different lengths with temporal characteristics. The analysis confirms that temporal pattern follows normal distribution which can be modeled by Gaussian function.

Effect of Dangling Bonds on Transient Response of p- i-n a-Si:H Photodiode

Abstract: The transient photocurrent of a-Si:H p-i-n photodiode as a three-color detector under simultaneously pulsed visible light illumination and forward voltage pulse at low reverse bias voltage and low frequency conditions were studied The characteristic transient response properties are attributed to the effect of the spatial distribution of defect states in the i-layer They act temporally as recombination or generation centers The results are useful in directing further investigation of the observed effect regard light illumination energy with application in color sensor in an active pixel sensor