A compact dual-band modified T-shaped CPW-fed monopole antenna

A compact, dual band coplanar waveguide fed modified T-shaped uniplanar antenna is presented. The antenna has resonances at 1.77 and 5.54 GHz with a wide band from 1.47–1.97 GHz and from 5.13–6.48 GHz with an impedance bandwidth of 34% and 26%, respectively. Also the antenna has an average gain of 3 dBi in lower band and 3.5 dBi in higher band with an average efficiency of 90%.

Modified Circular Patch Antenna

A circular miqrostrip antenna with a modified structure is presented. By adjusting the feed location along the circumference of the patch it is possible to match the antenna with a C microstrip line of any impedance. The impedance bandwidth and radiation characteristics are unaffected by this structural V modification.

A Compact Novel Slot-Loaded Dual-Frequency H-Shaped Antenna

A novel compact single-layer dual frequency microstrip antenna which uses an H-shaped geometry with two U-shaped slots embedded near the radiation edges, is presented. By changing the design parameters, the lower and higher resonant frequencies can be controlled easily, and a range of frequency ratios (1.716-2.363) can be obtained in this design. For the two operating frequencies of the proposed antenna, the same polarization planes and broadside radiation patterns are achieved. Compared to the regular dualfrequency patch antenna, this antenna can realize a significant size reduction

ACS fed printed F-shaped uniplanar antenna for dual band WLAN applications

An asymmetric coplanar strip (ACS) fed dual band F-shaped antenna covering the 2.4/5.2 GHz WLAN bands is presented. The optimized dimensions of the proposed uniplanar antenna are 21 mm × 19 mm when printed on a substrate of dielectric constant 4.4 and height 1.6 mm. The dual band nature of the antenna is brought about by the various current paths in the F-shaped structure and the ground plane. The antenna exhibits nearly omnidirectional radiation characteristics and moderate gain in both the operating bands. Details of the antenna design, simulation, and experimental results are presented and discussed.

Compact CPW-fed uniplanar antenna for multiband wireless applications

A compact coplanar waveguide (CPW) fed uniplanar antenna for Quad-band applications is presented. The Quad-band operation is realized by imposing various current paths in a modified T-shaped radiating element. The antenna covers GSM 900, DCS 1800, IEEE802.11.a, IEEE802.11.b and HiperLAN-2 bands and exhibits good radiation characteristics. This low profile antenna has a dimension of 32mm×31mmwhen printed on a substrate of dielectric constant 4.4 and height 1.6mm. Details of design with experimental and simulated results are presented

Resonant frequencies of circular-sided dual-port microstrip antenna

A dual-port microstrip antenna with a crescent shaped patch with excellent isolation betwecn the ports has been reportcd [I]. Since circular-sided geometries are inore compact than rectangular oncs, thcy find morc applications in microstrip arrays. The crcscent shaped antenna geometry [ I ] provides greater area rcductioii compared to other circular sided patches for broadband operation [2]. In this Lctter, formulac for calculating thc TM, I and TMZI mode resonant frequencies of this microstrip antenna, obtained by modifying the equations of a standard circular patch [3] are presentcd. Thcorctical results are compared with experimental observations aid the validity of the computation is established.

Implant-retained finger prosthesis with modified retention system

Background: Amputations affect both the physical and the psychological aspects of an individual, causing significant impact on self-esteem. The main causes of finger amputations are work-related accidents with dangerous machinery, road traffic accidents, and animal bites, as well as systemic diseases such as diabetes. This report aims to describe a simple technique for fabrication of implant-retained finger prosthesis with a modified base of the retention system.Case Description and Methods: The O-Ring retention system was used with a modified hexagon-shaped base and a metallic capsule adapted to the acrylic resin to attach the prosthesis to the implant.Findings and Outcomes: The prosthesis was made with silicone, and after osseointegration, it was installed without complications, leading to a patient satisfied with the end result and encouraged to return to social life.

Sea level measurement using single GNSS antenna SNR signals

This thesis presents a possible method to calculate sea level variation using geodetic-quality Global Navigate Satellite System (GNSS) receivers. Three antennas are used: two small antennas and a choke ring one, analyzing only Global Positioning System signals. The main goal of the thesis is to test a modified configuration for antenna set up. In particular, measurements obtained tilting one antenna to face the horizon are compared to measurements obtained from antennas looking upward. The location of the experiment is a coastal environment nearby the Onsala Space Observatory in Sweden. Sea level variations are obtained using periodogram analysis of the SNR signal and compared to synthetic gauge generated from two independent tide gauges. The choke ring antenna provides poor result, with an RMS around 6 cm and a correlation coefficients of 0.89. The smaller antennas provide correlation coefficients around 0.93. The antenna pointing upward present an RMS of 4.3 cm and the one pointing the horizon an RMS of 6.7 cm. Notable variation in the statistical parameters is found when modifying the length of the interval analyzed. In particular, doubts are risen on the reliability of certain scattered data. No relation is found between the accuracy of the method and weather conditions. Possible methods to enhance the available data are investigated, and correlation coefficient above 0.97 can be obtained with small antennas when sacrificing data points. Hence, the results provide evidence of the suitability of SNR signal analysis for sea level variation in coastal environment even in the case of adverse weather conditions. In particular, tilted configurations provides comparable result with upward looking geodetic antennas. A SNR signal simulator is also tested to investigate its performance and usability. Various configuration are analyzed in combination with the periodogram procedure used to calculate the height of reflectors. Consistency between the data calculated and those received is found, and the overall accuracy of the height calculation program is found to be around 5 mm for input height below 5 m. The procedure is thus found to be suitable to analyze the data provided by the GNSS antennas at Onsala.

Compact tunable bandstop filters using defected microstrip structure for multi-standard wireless systems

A novel compact tunable bandstop filter using Defected Microstrip Structure (DMS) is presented in this paper. The structure utilizes a modified T shaped DMS which helps in miniaturization of the filter. To verify the concept, one such filter was simulated, designed, fabricated and tested. Measurements on a fabricated tunable filter confirm the accuracy of the design procedure. The tuning range of 20% is achieved, ranging from 2.26 GHz to 2.747 GHz. Tuning is achieved by using NXP BB179 varactor diode. A nonlinear distortion evaluation in a tunable filter was experimentally verified. Experimental verification shows the filter is highly linear.

DEVELOPMENT AND ANALYSIS OF DUAL FREQUENCY MICROSTRIP ANTENNAS

Department of Elecctronics, Cochin University of Science and Technology

A Escola Normal do Pará e a introdução do ensino das Ciências Naturais no Pará (1870 a 1930)

A presente pesquisa tem o objetivo de analisar o currículo da Escola Normal do Pará, mais especificamente no que se refere às Ciências Naturais que constaram em sua estrutura, desde 1870 até 1930. Esta instituição foi criada em 1871 com o fim de formar professores para atuarem na instrução primária. Situada em Belém, que era o centro mais urbanizado da região, a Escola Normal estava entre as principais instituições da instrução pública paraense. As Ciências Naturais fizeram parte do primeiro currículo da Escola Normal do Pará, sendo elas a Física e a Química, contudo deixaram de fazer parte em 1874. O retorno das Ciências da Natureza se deu durante a Primeira República, por meio da Física, da Química e da História Natural, as quais se consolidaram ao longo deste período. A pesquisa analisa esta trajetória partindo do pressuposto que o currículo é um artefato social e histórico, sujeito a flutuações e que refletiu e continua a refletir as relações de poder envolvidas nos processos de seleção e transmissão cultural. Outra perspectiva analítica deste estudo considera o currículo como um meio de difusão científica, que também determina os modos que esta deve ocorrer. Sobre a difusão científica, parte-se do princípio que este processo não é simétrico, que os saberes científicos são criados em centros mais fortes e que ao serem difundidos para a periferia tem que interagir com a cultura que os recebe, os quais são conformados e modificados, sendo-lhes agregados valores diferentes dos que possuem nos países de centro. Assim, a pesquisa divide-se em três capítulos. O primeiro tem o objetivo de ver o desenvolvimento das Ciências Naturais no currículo do município do Rio de Janeiro, entre 1850 e 1890, que era a sede do governo central e o principal centro difusor de idéias para outras localidades do país, tanto em termos de educação quanto em outras áreas da administração pública. Com isso, analisa-se o desenvolvimento curricular do ensino primário, secundário e normal do Rio, mais especificamente em relação as Ciências Naturais, a partir das Reformas Coutto Ferraz (1854), Leôncio de Carvalho (1879) e Benjamin Constant (1890), as quais determinaram mudanças no currículo e na educação de modo geral. O segundo capítulo faz um resgate do desenvolvimento curricular da instrução pública primária e secundária paraense (1840-1870), isto para ver qual era o cenário curricular da instrução pública as vésperas da criação da Escola Normal, o que permite perceber e analisar que mudanças foram introduzidas por esta instituição neste contexto. O terceiro capítulo, num primeiro momento, revê a trajetória da Escola Normal do Pará e, num segundo momento, analisa-se o desenvolvimento do currículo normalista do Pará em relação as Ciências Naturais, de modo que é evidenciado a emergência e solidificação dos saberes científicos, tal como a distribuição de carga-horária em relação aos outros saberes e as próprias ciências constituintes do currículo.

Assessing the functional structure of molecular transporters by EPR spectroscopy

In this thesis, the self-assembled functional structure of a broad range of amphiphilic molecular transporters is studied. By employing paramagnetic probe molecules and ions, continuous-wave and pulse electron paramagnetic resonance spectroscopy reveal information about the local structure of these materials from the perspective of incorporated guest molecules. First, the transport function of human serum albumin for fatty acids is in the focus. As suggested by the crystal structure, the anchor points for the fatty acids are distributed asymmetrically in the protein. In contrast to the crystallographic findings, a remarkably symmetric entry point distribution of the fatty acid binding channels is found, which may facilitate the uptake and release of the guest molecules. Further, the metal binding of 1,2,3-triazole modified star-shaped cholic acid oligomers is studied. These biomimetic molecules are able to include and transport molecules in solvents of different polarity. A pre-arrangement of the triazole groups induces a strong chelate-like binding and close contact between guest molecule and metal ion. In absence of a preordering, each triazole moiety acts as a single entity and the binding affinity for metal ions is strongly decreased. Hydrogels based on N-isopropylacrylamide phase separate from water above a certain temperature. The macroscopic thermal collapse of these hydrogels is utilized as a tool for dynamic nuclear polarization. It is shown that a radical-free hyperpolarized solution can be achieved with a spin-labeled gel as separable matrix. On the nanoscale, these hydrogels form static heterogeneities in both structure and function. Collapsed regions protect the spin probes from a chemical decay while open, water-swollen regions act as catalytic centers. Similarly, thermoresponsive dendronized polymers form structural heterogeneities, which are, however, highly dynamic. At the critical temperature, they trigger the aggregation of the polymer into mesoglobules. The dehydration of these aggregates is a molecularly controlled non-equilibrium process that is facilitated by a hydrophobic dendritic core. Further, a slow heating rate results in a kinetically entrapped non-equilibrium state due to the formation of an impermeable dense polymeric layer at the periphery of the mesoglobule.

Morphological characterization of two new species of Dicontophrya (Ciliophora: Astomatia: Contophryidae) commensal of earthworms (Oligochaeta: Annelida) of ebebda and nkolbikogo (Cameroon)

Article

Development and Analysis of a Drum-Shaped Compact Microstrip Antenna

The thesis is the outcome of the experimental and theoretical investigations on a new compact drum-shaped microstrip antenna. A new compact antenna suitable for personal communication system(PCS), Global position System(GPS) and array applications is developed and analysed. The generalised cavity model and spatial fourier transform technique are suitably modified for the analysis of the antenna. The predicted results are compared with experimental results and excellent agreement is observed. The experimental work done by the author in related fields are incorporated as three appendices in this thesis. A single feed dual frequency microstrip antenne is presented in appendix A.Appendix B describes a new broadband dual frequeny microstrip antenna. The bandwidth enhancement effect of microstrip antennas through dielectric resonator loading is demonstarted in Appendix C.

A modified dual-band microstrip monopole antenna

A modified microstrip-fed planar monopole antenna with open circuited coupled line is presented in this paper. The operational bandwidth of the proposed antenna covers the 2.4 GHz ISM band (2.42-2.48 GHz) and the 5 GHz WLAN band (5 GHz to 6 GHz). The radiating elements occupy a small area of 23×8 mm2. The Finite Difference Time Domain method is used to predict the input impedance of the antenna. The calculated return loss shows very good agreement with measured data. Reasonable antenna gain is observed across the operating band. The measured radiation patterns are similar to those of a simple monopole antenna.