Expressions for the field intensities in a warm ionized plasma for two type of modes (electromagnetic and electroacoustic) pertaining to a microstrip matched coaxial termination are obtained using linearized hydrodynamic theory coupled with a vector function technique. The radiation power and directivity for the respective modes are evaluated for different ratios of plasma to source frequencies. It is observed that electromagnetic fields are similar to other microstrip antenna structures, but more directive in a particular direction. The electroacoustic mode exhibits a complete absence of multilobed structure, which was found for other antenna structures. The efficiency of this structure in a plasma is poor.

The impact of Bi₂O₃ addition on the structural, microhardness (Vickers microhardness (VHN)), resistivity and Hall coefficient measurements of Bi_3.4Pb_0.3Sr₂Ca_1.3−x RE_xCu₂O_y ceramic samples with various x and RE is investigated. X-ray diffraction results indicate that all the peaks belong to Bi: 2212 and 2201 phases. The moderate amount of 2212 phase exists as a major phase, while the 2201 phase as a minor. The net intensity of all peaks I_max for 2212 phase increases with Y as compared to undoped sample, followed by a gradual decrease with further increase in rare earth (RE) up to La. While the vice versa is recorded for both 2201 phase and VHN. Except Y sample, a good link between flake-type grains is observed in the SEM photographs of the considered samples. The electrical resistivity turns from quiet metallic for undoped sample to semiconducting behavior for all substituted samples without any …

Study of radiation properties of mismatched microstrip termination is carried out in warm ionized electron plasma medium. Linearised hydrodynamic theory coupled with vector wave technique is used to investigate radiation patterns and radiated power of a microstrip mismatched termination in one component electron plasma media for different plasma to source frequencies .These properties are used to compare the performance of an open circuit discontinuity with those of matched microstrip termination. Matched terminations are found more suitable for applications at higher frequencies than an open circuit discontinuity in the plasma medium though in free space they are less suitable

The effect of Cu and Mg doping at Polyvinyl Chloride (PVC) site on the the dielectric properties of (PVC) _1− x M _x in powder form with various M and x in powder form is investigated [M = Cu and Mg & (0.00 < x < 0.20]. The permittivityand the loss factor at 11.01GHz and room temprature of PVC in pure form as well as with some conducting impurities are measured. It is found that the permittivity and the loss factor are increaseing with doping content. These values are found to be higher in Mg doped samples as compared to Cu doped samples. Similar behaviour is also reported for the conductivity and relaxation time which are calculated for the considered samples. Our results are discussed in terms of parameters atomic structure, density and random distribution.

We report here the electrical conductivities measurements of Zn_1−xFe_xO ceramic samples with various x values (0.00⩽x⩽0.50). The measurements are made in both high and low temperature cases (300 K⩽T⩽523 K) and (20 K⩽T⩽300 K), respectively. Furthermore, the electrical conductivity data are well enough to calculate the activation energies E_a for the considered samples. The character of the conductivities curves is not absolutely symmetric to the response of temperature in both cases. Interestingly, two jumps are observed only in the conductivity curves at low temperatures. The onset temperatures of these jumps are increased by Fe up to 0.30, followed by a decrease at Fe=0.50. At constant Fe content, the conductivities are found to be increased over the temperature range in both cases. While, these values are decreased with the increase in the Fe content up to Fe=0.50. The conductivity character is …

In connection with the development of radio communication systems, microwave, millimeter range, one of the most important is the problem of creating compact solid-state radiation sources. The antenna is the effective interaction between electronic circuits and the outside world is an important component of any wireless connection trend toward line the use of high frequencies in modern communications. Solutions, space technology, about (30 Ghz), Local Multipoint Distribution (LMDS) at 28Ghz) antenna technologies to meet the new requirements of the card actively participated in the elaboration of the various subsystems for such active monolithic Phased Array Antenna. This document is primarily.This paper mainly studies the effect of plasma wave on the radiation properties of a conically depressed microstrip patch antenna .Using linearized hydrodynamic theory and potential function technique, the total directive gain and quality factor are calculated for different values of plasma to source frequency and different half-cone angles. It is observed that the directive gain and quality factor are changes considerably by changing the half-cone angle as well as a plasma to source frequency values. ©

This article addresses control for the chaos antisynchronization of a high frequency oscillator nuclear spin generator (NSG), which generates and controls the oscillations of the motion of a nuclear magnetization vector in a magnetic field. Based on the Lyapunov stability theory, an adaptive control law is derived to make the states of two identical (NSG) asymptotically anti-synchronized with uncertain parameters. Finally, a numerical simulation is presented to show the effectiveness of the proposed chaos antisynchronization scheme.

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