In this paper, an analysis of dual frequency resonance antenna is achieved by OM-shape microstrip patch antenna. The proposed antenna is analyzed using IE3D simulation software. The analysis of proposed structure is done by varying the dielectric constants and height of the substrate as well as gain and radiation pattern of the antenna is obtained. It observed that on varying the dielectric substrate the effect on proposed antenna is very effective.

No abstract

O] was used as precursor to prepare zinc oxide by thermal decomposition method. Its photoconductivity and dark-conductivity properties have been studied in air as well as in vacuum. Voltage dependence of photocurrent and dark-current has been observed at room temperature in air under UV-vis illumination. Stuructural study of ZnO microstructures has been analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Rise and decay curve in air exhibits anomalous behavior wherein the photocurrent decreases even during steady illumination. In vacuum, the rise of photocurrent becomes slow and prolonged.

The advancement in wireless communication is fueling the growth of innovative antenna array designs toward cost-effective and performance-oriented solutions. This paper proposed unconventional methods to design antenna arrays for multi-pattern synthesis without using attenuators or phase shifters. A low-cost alternative is proposed with “Time-modulation”-based antenna array capable of electronic scanning and beam steering. Here, “Time” is utilized as a fourth-dimensional (4D) array parameter, and that is why “Time-modulated” arrays are also called as 4D antenna arrays. The idea is to control the high-speed switch attached with each antenna periodically to produce desirable current and phase tapering. This article expanded the “Time-modulation” concept to synthesize multiple radiation patterns like monopulse patterns, scanned beam patterns, shaped beam patterns, and cosecant-squared beam patterns for multifunctional radar systems. Suitable time schemes are developed to generate the narrowband sum–difference patterns useful for monopulse radars. Simultaneous scanned beam patterns are also proposed for narrowband communication. Furthermore, to address the wideband applications, shaped flat-top beam patterns and cosecant-squared beam patterns are also proposed. In this regard, 20- and 16-element “Time-modulated” linear array antennas are developed, and the parameters of the arrays are controlled by suitably designed objective functions with quasi-Newton method (QNM)-based memetic optimization method. For this purpose, first a well-known genetic algorithm is adopted to search the potential trust regions in the exploration stage and QNM is used for fine-tuning. Furthermore, the Broyden’s good method-based direction-updating equation is used with QNM to improve the performance.