Juxtaposition of Women, Culture, and Nature in Alice Walker's Possessing the Secret of Joy

The present paper focuses on the tradition of women's circumsicion in the African tribe of Olinkan in Alice Walker's Possesing the Secret of Joy. The Olinkans are asked by the white settlers to stop women's mutilation, but Olinkan men continue this custom stealthily to ensure their patriarchial dominance. This novel is a complicated juxtaposition of two different types of oppression: one by White male colonizers over an African native land, and the other one by the native Olinkan men over native women. In this juxtaposition women and land are both victims exploited and manipulated by men, no matter Black or White. This novel is also seen as a fertile ground to analyze the dual domination of both nature and women by the Olinkan men and White colonizers who are both trying to impose their androcentric rules that are created to dominate women and land, respectively

Additively Manufactured Perforated Superstrate to Improve Directive Radiation Characteristics of Electromagnetic Source

© 2013 IEEE. Additively manufactured perforated superstrate (AMPS) is presented to realize directive radio frequency (RF) front-end antennas. The superstrate comprises spatially distributed dielectric unit-cell elements with square perforations, which creates a pre-defined transmission phase delay pattern in the propagating electric field. The proposed square perforation has superior transmission phase characteristics compared to traditionally machined circular perforations and full-wave simulations based parametric analysis has been performed to highlight this supremacy. The AMPS is used with a classical electromagnetic-bandgap resonator antenna (ERA) to improve its directive radiation characteristics. A prototype is developed using the most common, low-cost and easily accessible Acrylonitrile Butadiene Styrene (ABS) filament. The prototype was rapidly fabricated in less than five hours and weighs 139.3 g., which corresponds to the material cost of only 2.1 USD. The AMPS has remarkably improved the radiation performance of ERA by increasing its far-field directivity from 12.67 dB to 21.12 dB and reducing side-lobe level from-7.3 dB to-17.2 dB

All-metal wideband metasurface for near-field transformation of medium-to-high gain electromagnetic sources

Electromagnetic (EM) metasurfaces are essential in a wide range of EM engineering applications, from incorporated into antenna designs to separate devices like radome. Near-field manipulators are a class of metasurfaces engineered to tailor an EM source's radiation patterns by manipulating its near-field components. They can be made of all-dielectric, hybrid, or all-metal materials; however, simultaneously delivering a set of desired specifications by an all-metal structure is more challenging due to limitations of a substrate-less configuration. The existing near-field phase manipulators have at least one of the following limitations; expensive dielectric-based prototyping, subject to ray tracing approximation and conditions, narrowband performance, costly manufacturing, and polarization dependence. In contrast, we propose an all-metal wideband phase correcting structure (AWPCS) with none of these limitations and is designed based on the relative phase error extracted by post-processing the actual near-field distributions of any EM sources. Hence, it is applicable to any antennas, including those that cannot be accurately analyzed with ray-tracing, particularly for near-field analysis. To experimentally verify the wideband performance of the AWPCS, a shortened horn antenna with a large apex angle and a non-uniform near-field phase distribution is used as an EM source for the AWPCS. The measured results verify a significant improvement in the antenna's aperture phase distribution in a large frequency band of 25%

A System-Level Overview of Near-Field Meta-Steering

The paper provides a system-level overview of Near-Field Meta-Steering (NFMS) technology. The NFMS is upcoming antenna beam-steering method that uses the physical rotation of pair of thin metasurfaces that are placed in very close proximity to a high-gain feeding base antenna. This method neither uses any active radio frequency (RF) components nor physical tilting of any antenna part. It is for these reasons that this method yield antenna systems that superior to traditional electronically scanned phased array and mechanically rotated beamsteering antennas. The antenna systems can be developed for a range of applications including inflight connectivity, low-cost satellite terminal antennas to provide connectivity at remote places, and high-power micro- and millimetre-wave applications. The dynamic phase transformation that is achieved by the rotation of two metasurfaces, in a proof-of-concept prototype reported in 2017, indicate that an antenna beam can be scanned in a conical region having an apex angle of 102°

RFID Tag Design Using Spiral Resonators and Defected Ground Structure

This paper presents a simple generalized approach to design a compact chipless radio frequency identification tag. The proposed chipless tag encodes data into the spectral signature using a set of spiral resonators on both sides of substrate. Transmission amplitude component of the tag is used for data encoding. For miniaturization purpose, defected ground structure is used to reduce the circuit size by half compared to the conventional cascading technique. The proposed chipless tag operates between 4-6 GHz and produces 256 different binary strings through eight encoded bits. Measurement and simulation results verify the authenticity of this design

Compact quad-element high-isolation wideband mimo antenna for mm-wave applications

This paper presents a multiple-input multiple-output (MIMO) antenna system for millimeter-wave 5G wireless communication services. The proposed MIMO configuration is composed of four antenna elements, where each antenna possesses an HP-shaped configuration that features simple configuration and excellent performance. The proposed MIMO design can operate at a very wideband of 36.83-40.0 GHz (measured). Furthermore, the proposed MIMO antenna attains a peak gain of 6.5 dB with a maximum element-isolation of -45 dB. Apart from this, the MIMO performance metrics such as envelope correlation coefficient (ECC), diversity gain, and channel capacity (CCL) are analyzed, which demonstrate good characteristics across the operating band. The proposed antenna radiates efficiently with a radiation efficiency of above 80% at the desired frequency band which makes it a potential contender for the upcoming communication applications. The proposed design simulations were performed in the computer simulation technology (CST) software, and measured results reveal good agreement with the simulated one

Low-Cost Nonuniform Metallic Lattice for Rectifying Aperture Near-Field of Electromagnetic Bandgap Resonator Antennas

© 1963-2012 IEEE. This article addresses a critical issue, which has been overlooked, in relation to the design of phase-correcting structures (PCSs) for electromagnetic bandgap (EBG) resonator antennas (ERAs). All the previously proposed PCSs for ERAs are made using either several expensive radio frequency (RF) dielectric laminates or thick and heavy dielectric materials, contributing to very high fabrication cost, posing an industrial impediment to the application of ERAs. This article presents a new industrial-friendly generation of PCS, in which dielectrics, known as the main cause of high manufacturing cost, are removed from the PCS configuration, introducing an all-metallic PCS (AMPCS). Unlike existing PCSs, a hybrid topology of fully metallic spatial phase shifters are developed for the AMPCS, resulting in an extremely lower prototyping cost as that of other state-of-the-art substrate-based PCSs. The APMCS was fabricated using laser technology and tested with an ERA to verify its predicted performance. The results show that the phase uniformity of the ERA aperture has been remarkably improved, resulting in 8.4 dB improvement in the peak gain of the antenna and improved sidelobe levels (SLLs). The antenna system including APMCS has a peak gain of 19.42 dB with a 1 dB gain bandwidth of around 6%

Beam-Scanning Antenna Based on Near-Electric Field Phase Transformation and Refraction of Electromagnetic Wave Through Dielectric Structures

4siAn elegant combination of electric near-field phase transformation technique and electromagnetic-wave refraction, implemented through a pair of 3D printed dielectric structures, has been used to demonstrate a Ka-band beam-scanning antenna system. The system comprises a resonant-cavity antenna (RCA), which is used as a base antenna, a stepped dielectric (SD), and a dielectric wedge (DW). The SD is suspended above RCA in the near-field region to focus its broadside beam at an offset angle of 20 deg. The DW is placed above the SD and its two opening angles are selected such that the offset-angle focused beam tilts further and moves back to the broadside when the DW is co- and counter-aligned with the SD, respectively. The total height of the antenna system is 8:1 lambda_0, where lambda_0 is the free-space wavelength at the operating frequency of 30 GHz. The total cost of the material used for printing the two dielectric structures in prototyping is only 6 USD. It has been demonstrated through measurements of the prototype that by rotating the DWaround its own axis, the antenna beam can be scanned in both azimuth and elevation planes. The measured results indicate that antenna beam can effectively be scanned to any arbitrary angular position within a conical region having an apex angle of 68 deg, while maintaining peak-gain value within the 3 dB limit of the maximum gain of 16 dBi.openopenMuhammad U. Afzal; Ladislau Matekovits; Karu P. Esselle; Ali LalbakhshAfzal, Muhammad U.; Matekovits, Ladislau; Esselle, Karu P.; Lalbakhsh, Al

Printed closely spaced antennas loaded by linear stubs in a mimo style for portable wireless electronic devices

An easy-to-manufacture and efficient four-port-printed Multiple Input Multiple Output (MIMO) antenna operating across an ultra-wideband (UWB) region (2.9-13.6 GHz) is proposed and investigated here. The phenomenon of the polarization diversity is used to improve the isolation between MIMO antenna elements by deploying four orthogonal antenna elements. The proposed printed antenna (40 x 40 x 1.524 mm(3)) is made compact by optimizing the circular-shaped radiating components via vertical stubs on top of the initial design to maximally reduce unwanted interaction while placing them together in proximity. The measurements of the prototype MIMO antennas corroborate the simulation performance. The findings are compared to the recent relevant works presented in the literature to show that the proposed antenna is suitable for UWB MIMO applications. The proposed printed UWB MIMO antenna could be a good fit for compact portable wireless electronic devices