S. N. Salleh

Impedance modeling for a unit cell of the square loop frequency selective surface at 2.4 GHz

This paper presented an impedance modeling of the Equivalent Circuit (EC) for a unit cell of the square loop Frequency Selective Surface (FSS) structure. The unit cell of the square loop FSS is designed and simulated using the CST Microwave Studio software at 2.4 GHz based on industrial, scientific and medical bands (ISM) standard. The square loop FSS is simulated without FSS, with square FSS and FSS with slot. The investigation has been done on the length of substrate (s), width of substrate (w), length of square FSS (a) and length of slot (b). Imaginary (Im) component of EC has been modeled based on physical parameters of the square loop FSS in wavelength. EC gives a simple alternative method in FSS analyses which are useful for quickly predicting the performance of FSS.

A review of Genetic Algorithms and Parallel Genetic Algorithms on Graphics Processing Unit (GPU)

Genetic Algorithms (GAs) is proven to be effective in solving many optimization tasks. GAs is one of the optimization tools used widely in solving problems based on natural selection and genetics. This paper is intended to cover the study of GA and parallel GA and analyses its usage in CPU and GPU. One of the popular ways to speed up the processing time was by running them as parallel. The idea of parallel GAs may refer to an algorithm that works by dividing large problem into smaller tasks. Broad literature review in this paper includes a categorization of the GA operations that involved with some theories and techniques used in GA, presented with the aid of diagrams. This review attempts to study and analyse the behaviour of GA and parallel GA categories to work in GPU depending on the type of genetic algorithm. Parallel GA for GPU covers the architecture of Compute Unified Device Architecture (CUDA).

Application of Genetic Algorithm to the Design Optimization of Complex Energy Saving Glass Coating Structure

Attenuation of GSM, GPS and personal communication signal leads to poor communication inside the building using regular shapes of energy saving glass coating. Thus, the transmission is very low. A brand new type of band pass frequency selective surface (FSS) for energy saving glass application is presented in this paper for one unit cell. Numerical Periodic Method of Moment approach according to a previous study has been applied to determine the new optimum design of one unit cell energy saving glass coating structure. Optimization technique based on the Genetic Algorithm (GA) is used to obtain an improved in return loss and transmission signal. The unit cell of FSS is designed and simulated using the CST Microwave Studio software at based on industrial, scientific and medical bands (ISM). A unique and irregular shape of an energy saving glass coating structure is obtained with lower return loss and improved transmission coefficient.

Characteristic impedance modelling of circular loop and square loop frequency selective surface (FSS) on hybrid material

An impedance modeling for a unit cell of the circular loop and square loop FSS structure is presented in this paper. The unit cell of the circular loop and square loop FSS are designed and simulated using the CST Microwave Studio software at 2.4 GHz based on industrial, scientific and medical bands (ISM). The design FSS structure consists of FSS structures placed on the FR4 and glass. The reflection (S11) and transmission (S21) of the design FSS structure is analyzed based on the six types of configuration that have been set up. The hybrid material (FR4 and glass) effect the transmission and reflection signal of the FSS. The highest efficiency for circular loop FSS and square loop FSS are 91.4% and 88.1% with a return loss of -25.31 dB and -18.72 dB by using configuration 1. The frequency response of the FSS is shifted to the lower part when the hybrid materials are used. So, the size of the FSS can be reduced by using hybrid materials to achieve the desired frequency response.

Impedance of the unit cell of the frequency selective surface at 2.4 GHz

Equivalent Circuit (EC) method gives a simple alternative method in FSS analyses which are useful for quickly predicting the characteristic of FSS. Impedance of the EC for a unit cell of the design Frequency Selective Surface (FSS) structure is investigated in this paper. The unit cell of the design FSS structure consists of FSS structures placed on the FR4, glass and hybrid (FR4+glass). The square, circle and hexagon FSS structures without and with slot are designed and simulated using the CST Microwave Studio software at 2.4 GHz based on industrial, scientific and medical bands (ISM) standard. The resistance and the reactance of the impedance are depending on the material and shapes. This characteristic impedance can be used to design the advance FSS for similar ISM band.

Investigation of a square loop Frequency Selective Surface (FSS) on hybrid material at 2.4 GHz

The design FSS structure consists of square loop FSS structures placed on the FR4 board and glass. The square loop FSS is designed and simulated by using the CST Microwave Studio software for 2.4 GHz based on industrial, scientific and medical bands (ISM) standard. The reflection (S11) and transmission (S21) of the design FSS structure is analyzed based on the six types of configuration that have been set up. The hybrid material (FR4 board and glass) affects the transmission and reflection of the FSS. The highest efficiency for 2.4 GHz is 73% by using configuration 2.

The investigation of single, dual and tri-band frequency selective surface

The single, dual and tri-band Frequency Selective Surface (FSS) design structure is designed and simulated by using CST Microwave Studio software. The reflection (S11) and transmission (S21) of the design FSS structure is analyzed based on the six types of configuration that have been set up. All configurations are simulated with the same size of the FSS design structure. The hybrid material (FR4 and glass) affects the transmission and reflection signals of the FSS which led to the compact structure. The measurement results are agreed for all FSS design structures but the difference is due to the transmission losses.

Printed omnidirectional antenna for RFID applications

This paper proposed the dual band printed omnidirectional antenna for RFID applications at 2.45GHz. This antenna is made up from the double U-stubs and meander collinear structure. The antenna is based on the microstrip type of antenna. The return loss of the proposed antenna at 2.45GHz is -10.61dB and the bandwidth is 122MHz. The gain that has been achieved for this proposed antenna is 3.798dB.