Tarik Abdul Latef

Optical Nano Antennas: State of the Art, Scope and Challenges as a Biosensor Along with Human Exposure to Nano-Toxicology

The concept of optical antennas in physical optics is still evolving. Like the antennas used in the radio frequency (RF) regime, the aspiration of optical antennas is to localize the free propagating radiation energy, and vice versa. For this purpose, optical antennas utilize the distinctive properties of metal nanostructures, which are strong plasmonic coupling elements at the optical regime. The concept of optical antennas is being advanced technologically and they are projected to be substitute devices for detection in the millimeter, infrared, and visible regimes. At present, their potential benefits in light detection, which include polarization dependency, tunability, and quick response times have been successfully demonstrated. Optical antennas also can be seen as directionally responsive elements for point detectors. This review provides an overview of the historical background of the topic, along with the basic concepts and parameters of optical antennas. One of the major parts of this review covers the use of optical antennas in biosensing, presenting biosensing applications with a broad description using different types of data. We have also mentioned the basic challenges in the path of the universal use of optical biosensors, where we have also discussed some legal matters.

Aerogel Poly(butylene succinate) Biomaterial Substrate for RF and Microwave Applications

Polybutylene succinate (PBS) has become a potential candidate, similar to polypropylene (PP) and acrylonitrile butadiene styrene (ABS), for use as an organic plastic material due to its outstanding mechanical properties as well as high thermal deformation characteristics. A new composition of silica aerogel nanoparticles extracted from rice waste with PBS is proposed for use as a dielectric (εr = 4.5) substrate for microwave applications. A microstrip patch antenna was fabricated on the proposed dielectric substrate for multi-resonant ultra-wideband (UWB) applications. The performance characteristics of the proposed biomaterial-based antenna were investigated in a far-field measurement environment. The results indicate that the proposed biocompatible material-based antenna covered a bandwidth of 9.4 (2.3–11.7) GHz with stop bands from 5.5 GHz to 5.8 GHz and 7.0 GHz to 8.3 GHz. Peak gains of 9.82 dBi, 7.59 dBi, 8.0 dBi and 7.68 dBi were measured at resonant frequencies of 2.7 GHz, 4.6 GHz, 6.3 GHz and 9.5 GHz, respectively.

Efficiency enhancement for distributed power amplifier design with GaN HEMT technology

This paper presents the new design of distributed amplifier (DA) with control mechanism to enhance the efficiency performance by tuning the impedance at the gate termination adjustment network and applying drain line tapering topology. This distributed power amplifier (DPA) system is design based on the GaN high electron mobility (HEMT) transistor and simulated by using Advanced System Design tool (ADS). The detail of the design has demonstrated and achieved an output power of ∼40 dBm, flat gain at 10 dB, and bandwidth covering 100MHz to 2.4 GHz, with power added efficiency (PAE) of ∼40 %. As a result, this work has demonstrating significant improvement in efficiency over the conventional DA and offers wide band operation for public safety applications.

Compact double-p slotted inset-fed microstrip patch antenna on high dielectric substrate.

This paper presents a compact sized inset-fed rectangular microstrip patch antenna embedded with double-P slots. The proposed antenna has been designed and fabricated on ceramic-PTFE composite material substrate of high dielectric constant value. The measurement results from the fabricated prototype of the antenna show −10 dB reflection coefficient bandwidths of 200 MHz and 300 MHz with center resonant frequency of 1.5 GHz and 4 GHz, respectively. The fabricated antenna has attained gains of 3.52 dBi with 81% radiation efficiency and 5.72 dBi with 87% radiation efficiency for lower band and upper band, respectively. The measured E- and H-plane radiation patterns are also presented for better understanding. Good agreement between the simulation and measurement results and consistent radiation patterns make the proposed antenna suitable for GPS and C-band applications.

Moment method analysis of a helical antenna printed on a dielectric hemisphere

A printed spherical helical wire antenna is modelled using the method of moments. The effects of the dielectric sphere permittivity on the antenna characteristics have been studied. Computed results have been validated against simulations using a commercial software package.

Inversion response to optimize lumped-element circuits for metamaterial

Enhancing electromagnetic research on prior light bend mechanisms is a significant issue for composite material phenomena, and one that is not available in nature. The unit cell of metamaterial can be revised, such that it is significantly smaller than the free space of the wavelength. It is essential to extend the appropriate retrieval process to measure electrical and magnetic responses to the backward wave propagation and dispersion diagram characteristics. In this paper, we propose a retrieval process inversion response between known and unknown parameters of the lumped unit-cell circuits that optimizes the best fit parameters. By utilizing the optimization of particle swarm techniques, we provide appropriate values of periodic unit cells of CRLH transmission line circuits that matched with the microstrip implementation model. The group velocity of the wave is indicated in the parallel direction, whereas the phase velocity is in the anti-parallel direction. The dispersion diagram displayed a specifically left-handed and right-handed medium, and a tiny band gap appeared in the attenuation medium. The constitutive parameters of dielectric permittivity, permeability, and refractive index were obtained from the periodic composite transmission line circuits.

Making Meta Better: The Synthesis of New-Shaped Periodic Artificial Structures Suitable for Metamaterial Behavior Characterization

Extensive research in the electromagnetics area has been conducted recently with the goal of developing novel artificial metamaterials-or left-handed (LH) materials-at microwave frequencies. The idea of negative magnetic permeability and negative electric permittivity as electromagnetic properties for LH materials was initially theorized by Veselago in 1968. LH materials are not found in nature, so engineers must modify a structures geometry to achieve LH behavior.

A low-cost fiberglass polymer resin dielectric material-based microstrip patch antenna for multiband applications

Abstract The design analysis and prototype of a compact 8×10-mm2 planar microstrip line-fed patch antenna on a readily available, low-cost, reinforced-fiberglass polymer resin composite material substrate is presented in this article. The proposed compact-size antenna has been configured and numerically analyzed using the finite element method-based three-dimensional full-wave electromagnetic field simulator. The optimized design of the antenna has been fabricated on a printed circuit board (PCB), and experimental results have been collected for further analysis. The measurement results affirm the fractional impedance bandwidths of (return loss of less than -10 dB) of 38.78% (2.03–2.98 GHZ) and 16.3% (5.38–6.35 GHz), with average gains of 2.52 and 3.94 dBi at both lower and upper bands, respectively. The proposed dual resonant antenna shows the radiation efficiencies of 91.3% at 2.45 GHz and 87.7% at 5.95 GHz. The stable and almost symmetric radiation patterns and performance criteria of the antenna can successfully cover IEEE 802.11b/g/n, Bluetooth, WLAN, and C-band telecommunication satellite uplinks.

Gain enhancement for circularly polarized double layered printed hemispherical helical antenna arrays

To improve the performance of mobile satellite communications, such as for INMARSAT-M mobile vehicles, antenna with high gain and circular polarization over a wide angular range is important. With only 3-elements circularly polarized double-layered printed hemispherical helical antenna arrays that incorporated with parasitic helical wire in the structure, the array can produce significant improvement where it has been demonstrated that the gain and the 3 dB axial ratio (AR) bandwidth and beam width can be increased by properly adjusting the relative angular displacement δ1, δ2, δ3, and the inter-element spacing dx and dy. Experimental and theoretical results demonstrate that the array can produce a gain of 11 dBi, the 3 dB AR bandwidth of more than 11% with AR beam width of ~136°, and the mutual couplings between each element less than −23 dB at required 3 dB AR bandwidth frequency range. The antenna design is performed in computer simulation technology and verified by measurement.

Mutual Coupling Reduction of Dual Port Antenna Using Zero Index Metasurface Structure

The design and prototyping of a dual port planar printed quad band/Ultra wide band (UWB) patch antenna, with octagonal ring shaped metasurface structure (MSS) assimilated at the back to reduce mutual coupling between antenna elements, is presented. The proposed MSS incorporated UWB antenna has been designed and fabricated on a high permittivity (r15) ceramic filled biopolymer based sandwich structured dielectric substrate. Substantial reductions of mutual coupling (S21) between the dual port array elements of the proposed antenna has been achieved by assimilating a 6 × 9 octagonal ring shaped metasurface structure with near zero refractive index (NZRI) in the ground plane. Measurement results show that the proposed antenna with MSS loading has achieved the reflection co-efficient (S11 <-10 dB) bandwidths of 1.25 (2.25-3.5) GHz, 1 (4-5) GHz, 0.7 (5.9-6.6) GHz and 1.75 (7.7-9.45) GHz. Stable radiation patterns, with gains of 3.18 dBi, 2.96 dBi, 3.34 dBi and 9.61 dBi, have been measured at resonant frequencies of 2.85 GHz, 4.4 GHz, 6.2 GHz and 8.75 GHz.