Plasma-Based Artificial Magnetic Conductor for Polarization Reconfigurable Dielectric Resonator Antenna

Plasmonics - Polarization reconfigurable dielectric resonator antenna (DRA) backed by plasma artificial magnetic conductor (AMC) ground plane is designed and optimized for 10-GHz applications. The...     

Plasma Reflectarrays

This paper investigates the design of four different configurations of plasma reflectarrays. The results provide insight into different radiation characteristics of plasma reflectarrays. The proposed unit cell consists of a cubic glass box filled with argon gas energized with applied AC voltage. The reflectarray reflection coefficient phase variation is achieved by varying the plasma frequency of the energized gas. Four plasma reflectarrays for satellite applications at 12 GHz are proposed (centre feed centre beam, centre feed offset beam, offset feed centre beam, and finally, offset feed offset beam). The finite integration technique is used to analyse the plasma reflectarray.     

Reconfigurable Multi-beam On-Chip Patch Antenna Using Plasmonics Parasitic Graphene Strip Array

Plasmonics - This paper introduces on-chip patch antenna with electronic beam switching using graphene strip array for wireless communications at 415 GHz. The on-chip patch antenna is...     

Beam Steering Plasma Reflectarray/Transmitarray Antennas

The aim of this paper is to design and analyze plasma reflectarray/transmitarray antennas which include investigation of performance parameters for these antennas in free space. The unit cell element for both arrays consists of a cubic glass box with fixed dimensions filled by argon gas. The plasma frequency of the argon gas is varied by changing the applied voltage at both ends of the glass box. This allows steering the reflected/transmitted wave to a certain direction. Full-wave simulations using the finite element method (FEM) and finite integral technique (FIT) are used to optimize and analyze different plasma reflectarray and plasma transmitarray antennas. The plasma reflectarray antenna is composed of 13?×?13 elements and covered an area of 208?×?208 mm². A circular horn is used to feed the antenna at a distance of 20.8 cm (focal-to-diameter ratio (F/D)?=?1). The reflectarray is designed at f?=?12 GHz. The radiation patterns of the plasma reflectarray for scanning angles of 10° to 70° angles are illustrated. For larger scanning angles, significant sidelobe levels are produced. The maximum value of beam scanning gain patterns is reduced. The half-power beamwidth (HPBW) is increased. The plasma transmitarray is composed of 9?×?9 cell elements and covered an area of 72?×?72 mm². The feed is a linearly polarized circular horn. The F/D ratio is set to 1. The transmitarray is operating at f?=?15 GHz. The radiation patterns of the plasma transmitarray for scanning angles of ?40° to +40° are demonstrated. Significant sidelobe levels are produced at large scanning angles.     

Electronic Beam Switching of Circularly Polarized Plasma Magneto-Electric Dipole Array with Multiple Beams

In this paper, different array arrangements based on magneto-electric (ME) dipole antenna with wideband circular polarization (CP) characteristics are designed and investigated. Planar, triangular prism, square prism, and hexagonal prism array arrangements are considered. Each prism face has a sub-array comprises 2 × 2 ME-dipole elements. Each sub-array has wide impedance matching of 73.7%, a maximum gain of 16.6 dBi, and CP bandwidth of 78.2%. It employs the plasma frequency of the ME-dipole antenna to control its radiation characteristics. Frequency-independent lumped element equivalent circuit is constructed for a single antenna element. It is used to represent the antenna input impedance at different plasma electron densities with fixed physical structure. The proposed equivalent circuit comprises a single series section used for matching enhancement with feeder circuit, and three parallel tuned circuits corresponding to the three resonance frequencies in the input impedance. The best values of the equivalent circuit elements are computed using the particle swarm optimization (PSO) technique. Different array arrangements, planar, triangular, square, and hexagonal prism are designed to create single or multiple beams in different directions. An electronic beam switching is achieved by tuning in the plasma inside the ME-dipole in the desired direction. The radiation characteristics are analyzed and investigated using the finite integration technique (FIT).

     

Circularly Polarized Plasma Curl Antenna for 2.45 GHz Portable RFID Reader

In this paper, a broadband circularly polarized plasma curl antenna for portable RFID reader at 2.45 GHz is proposed. The antenna consists of a glass tube filled with argon gas and of about 1.4 wavelengths curled into one turn. A parametric study for the plasma curl antenna parameters is investigated. A simulated compact model for the portable RFID reader is proposed. The radiation characteristics of the plasma curl antenna enclosed inside a portable reader device are calculated. The behavior of plasma curl antenna is like a metal antenna when the signal is transmitted and received. Plasma antennas have many advantages as their design permit electrical, rather than mechanical control for their radiation characteristics. They are light weight, reconfigurable, can be energized, and de-energized in seconds, which prevent signal degradation. When a particular plasma antenna is not energized, its radiation does not affect the nearby elements and allowing other antennas to transmit or receive without interference. The radiation characteristics of the plasma curl antennas are investigated and analyzed using a finite integral technique.     

Polycyclic aromatic hydrocarbon residues in blood serum and human milk in Egypt,A pilot case study

This study was performed to monitor residues of polycyclic aromatic hydrocarbons (PAHs) in samples of human blood serum and human milk taken from volunteers from one rural area of Egypt. Extraction and clean-up processes were conducted using the Quick Easy Cheap Effective Safe methodology. PAH residue analysis was performed by Gas chromatography-flame ioninzation detector (GC-FID) and High performance liquid chromatography-fluorescence detector (HPLC-FLD) for blood and milk samples, respectively. Some confirmatory work was conducted using a mass spectrometer. The concentrations of PAH residues in blood samples were between 0.007 and 0.407 mg/l, with many of the congeners below detection limits. Residues of the most carcinogenic PAH congeners including benzo (a) pyrene were below the limits of detection in all blood samples, and total PAH concentrations have ranged between 0.156 and 3.61 mg/l. Regarding human milk samples, the sum of PAH concentrations ranged from 95.23 to 229.26 (µg/kg f.w.) with a mean of 154.35 (µg/kg f.w.). Benzo[a]pyrene was detected in concentrations ranging from 0.348 to 15.4, with a mean of 7.872 (µg/kg f.w.). Acenaphthylene, dibenzo [a,h]anthracene, acenaphthene, and naphthalene were the most abundant congeners in milk samples. Results indicated that the sources of PAHs in blood serum and human milk are of pyrogenic and petrogenic origin, respectively.     

Reconfigurable Circularly Polarized Hemispherical DRA Using Plasmonic Graphene Strips for MIMO Communications

Plasmonics - This paper investigates the radiation characteristics of a Hemispherical- Dielectric Resonator Antenna (DRA) loaded with graphene strips and fed by ridge-gap waveguide (RGW)...     

Dielectric Resonator Antenna Loaded with Reconfigurable Plasma Metamaterial Polarization Converter

In this paper, a plasma based metamaterial (MM) polarizer is optimized for linear to circular polarization conversion in Ku-band wireless applications. The plasma MM polarizer is design based on the transmission mode. The proposed plasma MM polarizer unit-cell element consists of back-to-back plasma arcs placed on the top and the bottom faces of a dielectric substrate. Polarization Conversion from linear polarized (LP) wave to circular polarized (CP) wave requires that the incident wave is splitted into two orthogonal components with equal magnitudes and π/2 phase difference. The polarization characteristics of the plasma MM polarizer have bandwidth of 17.5% centered around 13.7 GHz. A linearly polarized dielectric resonator antenna (DRA) is designed with impedance bandwidth of 27.05%. The LP-DRA loaded with plasma MM polarizer radiates CP-waves with improved gain of 8.89 dBi. Reconfigurable CP radiation right-hand, left-hand, or linear polarization is achieved when the argon gas in the lower, upper, or both arc-shaped containers is ionized to plasma state. The proposed plasma MM polarizer and the DRA structures are examined utilizing a full-wave simulator.