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This review article outlines research on nanoantennas in infrared bands and visible bands over the last one and half decades. The objective of this survey is to highlight basic insights and state-of-the-art developments based on applications. Besides, characterization and fabrication methods are also presented. The authors also proposed a dipole nanoantenna of multi-layer geometry which provides better efficiency and wider bandwidth. It offers an impedance bandwidth of 312 THz with maximum radiation efficiency and peak realized gain of 82.1% and 2.95 dBi, respectively. This proposed antenna provides an omnidirectional radiation pattern, which is a suitable candidate for energy harvesting and other photonic applications. [ABSTRACT FROM AUTHOR]

Due to the widespread use of low-power embedded devices in both industrial and consumer applications, research into the use of alternate energy sources has been sparked by the requirement for continuous power. Due to its accessibility and ability to be implanted, RF energy is always taken into consideration among the traditional energy sources that are currently available. There is a significant necessity for efficient RF front-ends, which must provide effective circular polarization (CP) features, effectiveness, feasibility from a design standpoint, and optimal usage of ambient RF signals accessible in the environment. So, for understanding their utilization in RF energy harvesting, a metasurface reflector-inspired CP-printed reconfigurable antenna integrated with a Greinacher voltage divider (GVD) rectifier circuit is reported. It offers broadband CP with fractional bandwidth > 25%, CP gain > 8.35 dBic, and directional radiation with the 3 dB angular beamwidth > 100° in the 3.5/5 GHz bands. With the integration of the rectifier circuit, a theoretical DC output > 4.8 V at 12 dBm is obtained. The acceptable impedance bandwidth, axial ratio bandwidth, antenna gain, antenna efficiency, and directional radiation with a 3 dB angular beamwidth value are studied and subsequently matched with the trade-offs (usage of diodes, complexity of DC biasing circuits, and attainment of polarization reconfigurability) obtained from the state of the art. A comprehensive study of the reconfigurable antennas is reported to highlight the findings as a widespread solution for these limitations in RF energy harvesting application. [ABSTRACT FROM AUTHOR]

In this research article, a metasurface (MTS)-loaded high-gain and broadband circularly polarized (CP) monopole antenna is reported. The proposed antenna configuration consists of a symmetric Y-shaped radiating monopole over a partial ground plane with extended twin parasitic conducting strips (PCS) loaded with a MTS reflector. To achieve left-hand circular polarization characteristics, a metallic copper strip is utilized to short the partial ground plane with one of the twin PCS [PCS(L)]. By using the grid-slotted sub patches on a rectangular MTS a reflector of 2λ fa × 1.65λ fa × 0.02λ fa is placed just below the monopole radiator at a height of 0.33λ fa , which provides broadened impedance (IBW) and 3 dB axial ratio bandwidth (ARBW) responses with high gain. The proposed prototype with an volumetric dimension of 1.33λ fa × 0.9λ fa × 0.02λ fa at f a = 5 GHz is designed and characterized. It exhibits a measured IBW of 48.45% (3.57–5.89 GHz), ARBW of 25.25% (4.21–5.42 GHz), and CP gain of > 8.35 dBic with the antenna efficiency of > 75% in the desired operating frequency bands. The obtained performances of the proposed MTS antenna confirm its suitability for RF energy harvesting application. [ABSTRACT FROM AUTHOR]

A person's self-concept is motivating force in his behavior. The individual acts in accordance with how he sees himself at the moment. If he feels that he is misunderstood or discriminated against, he will act like a martyr. If he feels that people accept him, he will act in a friendly cooperative way. The self- concept is the dominant elements in the personality pattern; it governs the individual's characteristics reaction to people and situations and determines the quality of his behavior. In this research paper, the researcher focused on the meaning of self- concept with its components, theories and categories i.e., the term self- concept refers to the correlation of the cluster of the most personal meanings, a person attributes of self, upon which he places the highest value of himself. [ABSTRACT FROM AUTHOR]