M. Md Shukor

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.

Equilateral triangular microstrip patch antenna with spur lines embedded

This paper presents an equilateral triangular microstrip antenna with spur lines. The proposed antenna, comprising a triangular planar patch element embedded with two spur line slots. The simulation and fabrication process are performed to understand the characteristics of the proposed antenna. The simulation result is compared with the fabricated antenna. The targeting frequency of this antenna is 0.90 GHz (first resonant frequency) and 1.80 GHz (second resonant frequency). The proposed antenna can improve the bandwidth of GSM 1800 up to 100 MHz. It shows the return loss of - 16.176 dB, bandwidth of 33 MHz (0.919 GHz to 0.952 GHz) and a gain of 3.52 dB first resonant frequency. At second frequency, the return loss are - 28.159 dB with a bandwidth of 115 MHz (1.714 GHz to 1.829 GHz) and gain of 3.380 dB.

Design of rectangular stacked patch antenna with four L-shaped slots and CPW-fed for WiMAX application

In this work, a novel coplanar waveguide (CPW) fed rectangular patch antenna embedded with four L-shaped slots for WiMAX application was proposed. This antenna is designed by using an FR4 epoxy board with dielectric constant, εr = 4.4, tangent loss, tan δ = 0.019 and the thickness of substrate, h = 1.6mm. There are two methods applied in this antenna to improve the characteristic of the antenna. The first method is by adding four L-shaped slots on the patch of the antenna to improve the bandwidth of the antenna. In order to improve the bandwidth and gain of the antenna, rectangular stacked patch above the basic patch have been suggested. The simulation of the antenna was done by using Computer Simulation Technology (CST) simulation software. Then, the fabricated antenna had been done to compare with the simulation result. It shows that the addition of a stacked patch on the microstrip patch antenna effect to achieve higher gain performance with 2.687 dB compared with an antenna without stacking patch with only 1.685 dB.

Dual layer rectangular microstrip patch antenna with H-slot for 2.4 GHz range applications

In this work, a dual layer rectangular microstrip patch antenna with H-slot is proposed for improving the return loss and enhanced gain at 2.4 GHz and 2.45 GHz. The antenna is designed by using CST Microwave Studio is used to design the mathematically based on the rectangular microstrip patch antenna. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the RFID frequency range. It is found that this antenna shows - 18.584 dB at 2.45 GHz and - 19.692 dB at the resonant frequency of 2.442 GHz. At desired along this frequency band, the gain 2.228 dB at 2.442 GHz and 2.756 dB at 2.45 GHz is achieved.

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.

Design a 3.5 slot antenna using coplanar waveguide (CPW) for dual band application

The proposed antenna is designed to overcome the demand in dual band issues. The basic shape structures of antenna are designed at frequency 2.4 GHz based on radiating structure 5 and 5.2 GHz based on radiating structure 3. Then, the changes on the position of radiating structure 3 have been carried out to investigate the effect for dual band. The coplanar waveguide technique is used to design the basic structure 3.5 antenna to achieve dual band resonant frequencies. Then, the position of the radiating structure 3 is turned to 90° so that the resonant frequencies can achieve at 2.4 GHz and 5.2 GHz. The results from the simulations were then validated with experimental measurements of a prototype that has been fabricated. The return loss for both resonant frequencies are less than -10 dB where 90% of the input signal is transmitted and only 10% of the input signal is reflected back.

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.