M. T. Ali

Frequency reconfigurable aperture-coupled microstrip patch antenna using Defected Ground Structure

This paper designs and simulates frequency reconfigurable microstrip patch antenna using Defected Ground Structures (DGS) with aperture coupled feed line. Single element with two regular slots etched on the ground layer has been designed to represent two resonant frequency 7.5 GHz and 8.85 GHz. Comparison two antenna designs without and with DGS structure is reported in this paper. Simulated results shows that etched DGS structure on the ground plane can eliminate one of the resonant frequencies. Effect of DGS structure on the designed antenna based on switching mode at the feed line.

An alternative approach to design conductive hybrid cover yarns for efficient electromagnetic shielding fabrics

E-Textiles have gained enormous attention due to their specific characteristics in various non-conventional applications such as electromagnetic shielding materials. With the advent of various high frequency-driven devices, the need to restrict the non-ionizing radiations from their undesired effects became imperative. Due to the ease of production, better electrical conductivity and durability, the conductive hybrid cover yarns with continuous metallic filaments have earned its place as the most convenient form of yarns to develop E-textiles. However, controlling the amount of conducting material in yarns poses a challenge as the increase in size of the metallic filaments are associated with reduced electromagnetic shielding effectiveness due to increased stiffness of yarns, which resists in proper interlacement and hence causes openness in fabrics. The proposed design of conductive hybrid cover yarns is proven to have better tensile properties and modulus, therefore this design is more suitable to produced fabrics with higher cover factors. The amount of conducting material in the proposed design increased significantly without changing the size of the continuous filaments. Moreover, 99.9% shielding effectiveness is achieved with this increased metal content in fabrics in S-band and partly C-band microwave frequencies.

Accurate feed position designing for Malaysia beam coverage

For satellite communication, precise Malaysia coverage is requesting. In this paper, multi beam coverage is studied. In order to arrange multi beams at exact positions, exact feed position are determined through focal region ray tracings. Then, a multi beam reflector antenna is designed and beam allocations are examined. Adequateness of feed position determination is ensured by exact beam position achievement.

Parametric Study of Integrated Stacked Microstrip Antenna with Light Emitting Diode (LED) for Wi-Fi Application

In this paper the parametric study of integrated rectangular stacked microstrip antenna with Light Emitting Diode (LED) for Wi-Fi application is presented. There are two objectives in this design: one is the analysis of when the LED placed at difference layer from the radiating patch, another one analysis is by looking at the electrical connection of 18 LEDs in series, parallel and a combination of series and parallel. The antenna was simulated design and optimized at 2.45 GHz using Computer Simulation Technology (CST) with permittivity, εr = 4.5 and thickness, h = 1.6mm on FR4 substrate. The LED placed on the top substrate as the parasitic element. The radiating patch is placed at the second layer of substrate and aperture coupled feeding network was used in this design. The antennas are reasonable well matched at their corresponding frequency of operations. The simulation results have shown that the antenna works well.

A design of single patch antenna with Leucaena Leucocephala Wood Plastic Composite (WPC) substrate

The fabrication of single patch antenna for proposed Leucaena Leucocephala (“Petai Belalang”) Wood Plastic Composite (WPC) substrate board and FR4 substrate board is presented in this paper. The experiment objective was to measure the performance of an antenna fabricated on the proposed board by comparing the performance in term of Dielectric Constant value, Tangent Loss value, Return Loss, Radiation Pattern and Gain with antenna fabricated onto FR4 material substrate board. The idea is to find the potential alternative board replacing conventional printed circuit board (PCB) using commercial FR4 material. The dielectric constant and tangent loss value for both proposed and FR4 substrate board were analyzed with Agilent 85070E Dielectric Probe Kit method. The Fabricated proposed boards were studied in the frequency range of 2.2 to 3.3 GHz since this board will be used in ISM band application that occupied 2.45 GHz frequency spectrum. The parameter composition of proposed board on this paper was focused only on one density composition that is 70% of polypropylene and 30% of leucaena leucocephala filler wood with particle size maintained at 150 μM and moisture content of the filler is less than 5%. The indoor Practical Antenna Measurement method was used to prove the proposed antenna can be used as transmitting antenna and all result obtained were form as data and graph analysis.

Comparative analysis for multilayer stacked substrates microstrip patch antenna

the comparative analysis for multilayer stacked substrates microstrip patch antenna has been study in this paper. The analysis is carried out to investigate the effect of adding a difference thickness substrate into antenna design for indoor application. An aperture slot feeding technique is used to provide wider bandwidths, and better isolation between antennas and the feed network. The analysis will focusing with two objective, one is to find out the structure that can maintain the antenna resonant frequency and the second objective is to increase antenna thickness by stacking substrate at difference layer from the radiating patch that hope can improve antenna performance. The antenna was simulated design and optimized at 2.45 GHz using Computer Simulation Technology (CST) with permittivity, εr = 4.3 and thickness, h = 1.6mm on FR4 substrate. The third substrate placed on the top antenna structure to improve antenna performance. The radiating patch is placed at the second layer of substrate and aperture coupled feeding network was used in this design. The antennas are reasonable well matched at their corresponding frequency of operations. The simulation results have shown that the antenna works well.

Simulation of radiation pattern reconfigurable microstrip patch antenna using feeding delay line technique

This paper proposes radiation reconfigurable patch antenna using feeding delay line technique. By using simulation and optimization from Computer Simulation Technology (CST) the 2 × 2 antenna array is designed and investigated. The direction of radiation pattern is controlled by interchanging two different lengths of corporate feeding network using OPEN and SHORT states of feeding line network. Working at 7.5 GHz for meteorology application, three directions of radiation pattern are obtained from the proposed reconfigurable antenna according to the states of feeding line network, −30 degree, 0 degree and +30 degree. Good results from the simulation and optimization analysis promise the feasibility of the proposed technique.

Design of serial feeds for a bifurcated beam of bend-array configuration

This paper presents the design of serial feed radiators in cylindrical lens antenna system for mobile base station application. The authors are developing a cylindrical lens antenna featuring a simple configuration compared to the present array antenna configuration. In order to achieve the cylindrical lens antenna, bifurcated beam radiation shall be produced by the feed elements. In this paper, the bifurcated beam is achieved by adopting a bend-array configuration, consisting of four rectangular array elements with serial feed network. To ensure good and balance performance of the array antenna, the orientation of electric fields and the excitation amplitude of each element are considered. The optimized array structure is then arranged in bended structure to obtain the bifurcated beam pattern. To verify the radiation characteristic, simulation result of the bifurcated beam radiation is shown in terms of the current distribution. Good agreement between the beam pattern and the current distribution is obtained, showing that the serial feed network is accurate and effective to produce the bifurcated beam radiation for cylindrical lens antenna system.

Beam scanning of phased array antenna using phase modification method for satellite application

This paper presents the design of a 1×4 microstrip array antenna operating at 6.3GHz for C-band communication satellite application. The project aims to investigate the ability of the array to control the direction of the main lobe through a systematic least mean square method and to validate the design through accurate electromagnetic analysis. The array element consists of rectangular microstrip patch fed by inset feed. The single rectangular microstrip patch size and feed position is obtained by theoretical calculation, MATLAB and CST Studio software simulation. Based on the single element design, an array of four elements with equal sizes and spacing is designed. The desired beam direction is determined through passive feed control of the transmission line length to adjust the phase of the radiation pattern. A good performance antenna with 10.78dB gain and 42.46% efficiency is produced. A clear relation between phase coefficient and beam direction has been achieved.

The recognition of biocomposite antenna substrate via coaxial probe method and substrate sensor

The research paper covered two novelty that measures the dielectric properties by using the coaxial probe method for 1 GHz to 20 GHz and recognition of the proposed substrate by using substrate sensor circuit. The dielectric properties measurement involved KEYSIGHT 85070E probe kit and the substrate recognition circuit using the microcontroller PIC16F877A with light depending resistor sensor. The substrate sensor used visibility method to cascade the analogue input with the changes of the light source. The stability output for dielectric constant (1.86 to 3.45) and loss tangent (0.0066 to 0.0754) obtained for five different compositions of biocomposite antenna substrate. Besides that, the recognition of the proposed substrate succeeded with the microcontroller recognise each of the substrates and display via a liquid crystal display the type of proposed substrate according to the composition. The stability of the dielectric properties measurement results distributes by the implementation of measuring tool to overcome the warping issue. The circuit performed as expected to recognise each of the proposed substrates and offer portability for the substrate recognition process.