Stacked square microstrip antenna with a shorting post for dual band operation in WLAN applications

A small and wideband antenna for dual band (2.4/5.2 GHz bands) operation is presented. The proposed antenna has a shorting post and slits to miniaturize the size of patch. The bandwidth in the low frequency band (the 2.4 GHz band) increases as the length of the shorting post between the upper and lower patches increases. The lengths of the square patch of the proposed antenna are around 0.10lambda2.45GHz and 0.21lambda5.25GHz. The bandwidths are 5.2% and 11.0% in the 2.4G Hz and 5.2 GHz bands, respectively.2006 Asia-Pacific Microwave Conference : Yokohama, Japan, 2006.12.12-2006.12.1

Design of a Wideband L-Shape Fed Microstrip Patch Antenna Backed by Conductor Plane for Medical Body Area Network

This paper describes a compact patch antenna intended for medical body area network. The antenna is fed using a proximity coupling scheme to support the antenna that radiates in the free space and on the human body at the 2.45 GHz ISM band. The conductor plane is placed 2 mm or 0.0163λ0 (λ0 is free space wavelength at 2.45 GHz) below the antenna to reduce backward radiation to the human body. Separation distance must be kept above 2 mm, otherwise, gain of the proposed antenna decreases when antenna is situated on the human body. The L-shape feed line is introduced to overcome impedance mismatch caused by the compact structure. The coupling gap between the proposed antenna and the length of the L-shape feed line are optimized to generate dual resonances mode for wide impedance bandwidth. Simulation results show that specific absorption rate (SAR) of the proposed antenna with L-shape feed line is lower than conventional patch antenna with direct microstrip feed line. The proposed antenna achieves impedance bandwidth of 120 MHz (4.89%) at the center frequency of 2.45 GHz. The maximum gain in the broadside direction is 6.2 dBi in simulation and 5.09 dBi in measurement for antenna in the free space. Wide impedance bandwidth and radiation patterns insensitive to the presence of human body are achieved, which meets the requirement of IoT-based wearable sensor

Comparison of numerical solutions of hollow cylindrical dipole antennas

The current distributions of hollow cylindrical dipole antennas are calculated by using WIPL-D and AWAS. The relative error of feed point current and the root mean square error of current distribution are compared. As the criterion for accuracy of calculated results, the numerical solutions of Pocklington\u27s integral equation on the antenna surface with the surface current expansion functions satisfying the edge condition at the antenna ends are adopted.ACES-2002, March 18-22, 2002, Monterey, Californi

Electric currents distributions on finite patch conductor of microstrip antenna

The electric currents on the upper, lower and side surfaces of the finite patchconductor of a circular microstrip antenna are calculated by using the methodof moment in the spectral domain. The electric current on the lower surfaceis much bigger than that on the upper surface and the input impedance ofmicrostrip antenna depends on the electric current on the lower surface.2003 Asia Pacific Microwave Conference, November 4-7, 2003, Sheraton Walkerhill Hotel, Seoul, Kore

Wall Admittance of a Circular Microstrip Antenna

The formulation of the wall admittance of a circular microstrip antenna by the spectral domain method is presented. The circular microstrip antenna is calculated using the cavity model. The electromagnetic fields within the antenna cavity are determined from the impedance boundary condition at the side aperture. The contribution from the region outside the antenna is taken into account by the wall admittance. The wall admittance is defined by the magnetic field produced by the equivalent, magnetic current at the aperture. The magnetic field is calculated by the spectral domain method. The wall admittances obtained by this method are compared with the results calculated by Shen. The calculated input impedances of the microstrip antenna agree fairly well with the experimental data for the substrate thickness of up to 0.048λ_g. The formulation of wall admittance presented here is easily applicable to arbitrarily shaped microstrip antennas

Cold-shock eliminates female nucleus in fertilized eggs to induce androgenesis in the loach (Misgurnus anguillicaudatus), a teleost fish

<p>Abstract</p> <p>Background</p> <p>Androgenesis (all-male inheritance) is generally induced by means of irradiating the eggs to inactivate the maternal genome, followed by fertilization with normal sperm. In fish, the conventional technique for induced androgenesis has been applied for rapid fixation to traits, recovery of cryopreserved genotypes, sex-control, etc. A new method of androgenesis that eliminates the need to irradiate the egg was proposed using the loach, <it>Misgurnus anguillicaudatus </it>(a teleost fish).</p> <p>Results</p> <p>When the eggs of wild-type females were fertilized with sperm of albino or orange phenotype males and cold-shocked at 0 to 3°C for 60 min duration just after fertilization, generally more than 30% (with a peak of 100%) of the hatched progeny were androgenotes. While a few of them were the normal diploid, most of them turned out to be abnormal haploid. All-male inheritance was verified by the expression of the recessive color trait (albino or orange) and microsatellite genotypes comprising only paternally derived alleles. Nuclear behavior after the cold-shock treatment was traced by microscopic observation of DAPI (4'6-diamidino-2-phenylindole)-stained samples and hematoxylin-eosin stained histological sections, and the extrusion of egg (maternal) nucleus was observed in eggs treated in the optimum timing.</p> <p>Conclusion</p> <p>In this paper, we demonstrate that cold-shock treatment (at 0 and 3°C) of loach eggs for 60 min just after fertilization successfully induces androgenetic haploid development. The most likely mechanism of cold-shock induced androgenesis is an elimination of the egg nucleus together along with the second polar body and subsequent development of a decondensed sperm nucleus or male pronucleus.</p

Ambipolar suppression of superconductivity by ionic gating in optimally-doped BaFe2(As,P)2 ultrathin films

Superconductivity (SC) in the Ba-122 family of iron-based compounds can be controlled by aliovalent or isovalent substitutions, applied external pressure, and strain, the combined effects of which are sometimes studied within the same sample. Most often, the result is limited to a shift of the SC dome to different doping values. In a few cases, the maximum SC transition at optimal doping can also be enhanced. In this work, we study the combination of charge doping together with isovalent P substitution and strain by performing ionic gating experiments on BaFe$_2$(As$_{0.8}$P$_{0.2}$)$_2$ ultrathin films. We show that the polarization of the ionic gate induces modulations to the normal-state transport properties that can be mainly ascribed to surface charge doping. We demonstrate that ionic gating can only shift the system away from the optimal conditions, as the SC transition temperature is suppressed by both electron and hole doping. We also observe a broadening of the resistive transition, which suggests that the SC order parameter is modulated nonhomogeneously across the film thickness, in contrast with earlier reports on charge-doped standard BCS superconductors and cuprates.Comment: 10 pages, 5 figure

A Fast Runtime Visualization of a GPU-Based 3D-FDTD Electromagnetic Simulation

In this paper, we present design and implementation of a fast runtime visualizer for a GPU-based 3D-FDTD electromagnetic simulation. We focus on improving the productivity of simulator development without compromising simulation performance. In order to keep the portability, we implemented a visualizer with the MVC model, where simulation kernels and visualization process were completely separated. For high-speed visualization, an interoperability mechanism between OpenGL and CUDA was used in addition to efficient utilization of programmable shaders. We also propose an asynchronous multi-threaded execution with a triple-buffering technique so that developers can concentrate on developing their simulation kernels. As a result of empirical visualization experiments of electromagnetic simulations for practical antenna design, it was revealed that our implementation achieved a rendering throughput of 90 FPS for a view port of 512 x 512 pixels, which corresponds to a 12.9 times speedup compared to when the OpenGL-CUDA interoperability mechanism was not utilized. When a standard visualization throughput of 60 FPS was selected, the performance overhead imposed by the visualization process was 15.8%, which was reasonably low compared to a speedup of the simulation kernel gained by the GPU acceleration

An ancestral haplotype of the human PERIOD2 gene associates with reduced sensitivity to light-induced melatonin suppression.

Humans show various responses to the environmental stimulus in individual levels as "physiological variations." However, it has been unclear if these are caused by genetic variations. In this study, we examined the association between the physiological variation of response to light-stimulus and genetic polymorphisms. We collected physiological data from 43 subjects, including light-induced melatonin suppression, and performed haplotype analyses on the clock genes, PER2 and PER3, exhibiting geographical differentiation of allele frequencies. Among the haplotypes of PER3, no significant difference in light sensitivity was found. However, three common haplotypes of PER2 accounted for more than 96% of the chromosomes in subjects, and 1 of those 3 had a significantly low-sensitive response to light-stimulus (P < 0.05). The homozygote of the low-sensitive PER2 haplotype showed significantly lower percentages of melatonin suppression (P < 0.05), and the heterozygotes of the haplotypes varied their ratios, indicating that the physiological variation for light-sensitivity is evidently related to the PER2 polymorphism. Compared with global haplotype frequencies, the haplotype with a low-sensitive response was more frequent in Africans than in non-Africans, and came to the root in the phylogenetic tree, suggesting that the low light-sensitive haplotype is the ancestral type, whereas the other haplotypes with high sensitivity to light are the derived types. Hence, we speculate that the high light-sensitive haplotypes have spread throughout the world after the Out-of-Africa migration of modern humans