B. H. Ahmad

Study and Simulation of an Edge Couple Split Ring Resonator (Ec-SRR) on Truncated Pyramidal Microwave Absorber

Split ring resonator (SRR) structure can potentially be incorporated onto the truncated pyramidal microwave absorber. This study considers three difierent patterns of edge couple split ring resonator (EC-SRR) designs. Each EC-SRR design is then placed onto the truncated pyramidal microwave absorber. Outer split gap dimension widths of the EC-SRR are varied, and the various S21 performances are compared. This EC-SRR truncated pyramidal microwave absorber is simulated using CST Microwave Studio simulation software. The study and simulation are performed in low frequency range (0.01GHz to 1GHz) as well as in microwave frequencies range (1GHz to 20GHz). Simulation results of this EC- SRR show improvement of re∞ection loss and S11 performance in the high frequency range of the pyramidal truncated microwave absorber.

Design and analysis of broadband high isolation of discrete packaged PIN diode SPDT switch for wireless data communication

A design and analysis of broadband high isolation of discrete packaged PIN diode Single-Pole Double-Throw (SPDT) switch is presented. Many applications of wireless data communication are implementing Time Division Duplex (TDD) switching such as UMTS-TDD (in 3G technologies), LTE (in 4G technologies), HiperLAN, HiperMAN, WiFi, WiMAX and WiBRO. A broadband high isolation of SPDT switch is needed to provide these multimarket applications at different frequency bands. In this paper, three different circuit topologies (Type A, Type B and Type C) targeted for broadband high isolation are designed and analyzed. The SPDT switches are based on the discrete packaged PIN diode that available in the market for switching control. Analysis of the various configurations is done in order to select the most suitable topology for broadband high isolation SPDT switch. As results, Type C has been chosen for prototyping and measurement. In simulation and measurement, the isolation is higher than 25 dB from 0.5 to 3 GHz compared with Type A and Type B.

Effect of single complimentary split ring resonator structure on microstrip patch antenna design

This paper had been comparing the performance of the normal patch antenna with single complimentary SRR patch antenna. Four different shapes of single complimentary split ring resonator structure had been incorporated into the microstrip patch antenna - square, circular, triangular, and rhombic. This simulation works had been done in CST Microwave Studio simulation software. The operating frequency of this antenna is 2.40 GHz for Wireless Local Area Network (WLAN) application. The parameters that considered in these works are return loss, resonant frequency, input impedance, gain, radiation pattern and bandwidth. The focusing parameter is to achieve the best gain performance that obtained from the single complimentary split ring resonator patch antenna. The addition of square SRR onto patch antenna will improve the gain from 6.334 dB to 6.508 dB.

Reconfigurable matched bandstop filter

This paper demonstrates a reconfigurable matched bandstop filter. The filter is based on a lossy allpass network. The lossy allpass network demonstrates the concept and design of perfectly matched bandstop response with a perfect matched at all frequencies. The filter is based on the half-wavelength λ over 2 resonator with gap coupling, parallel with an allpass nominally-90°-phase-shift element, which can be optimized to achieve high Q-factor. The reconfigurable matched bandstop filter can be realized by using PIN diodes as a switching element. This filter provides two state of operation under two conditions. The first condition is that the filter will produce allpass response when the PIN diodes are turned ‘ON’. The second condition is that the filter will produce bandstop response when the PIN diodes are turned ‘OFF’. Theoretical analysis together with experimental results is presented in this paper.

Investigation of dual and triple meander slot to microstrip patch antenna

A dual and triple microstrip meander slot antenna is presented for Wireless Local Area Network (WLAN) application. The antenna also has the potential to be used as the receiving antenna in an energy harvesting system. The proposed antenna comprises a rectangular microstrip patch element embedded with meander slots. The parametric study is performed to investigate the characteristic of microstrip patch antenna with double meandered slots compared to the same microstrip patch antenna with triple meandered slots. Microstrip patch antenna with dual meander slot can achieve return loss until -24.54dB. However the gain of the antenna, 1.46 dBi is lower than microstrip patch antenna with triple meander slot which is 4.28 dBi. Other antenna parameters are also investigated such as bandwidth, radiation patterns and directivity have been observed and simulated. Measurement results are also recorded in this paper.

Development Of Pyramidal Microwave Absorber Using Sugar Cane Bagasse (SCB)

The need to flnd ways to efiectively utilize the large quantities of agricultural waste that are produced is indicative of the huge potential associated with producing an alternative pyramidal microwave absorber for anechoic chamber-testing applications. We propose the development of a pyramidal microwave absorber that can use sugar cane bagasse (SCB), a byproduct from the production and processing of sugar cane, as the absorbent. In this paper, we report the results of our use of dielectric probe measurement to determine the dielectric constant and loss tangent of SCB. These values were used to model and simulate an SCB pyramidal microwave absorber in Computer Simulation Technologys (CSTs) Microwave Studio. This absorber was operated in the microwave frequency range between 0.1GHz and 20.0GHz.

Performance Analysis of Hexagon-Diamond Search Algorithm for Motion Estimation

To achieve a high compression ratio in coding video data, a method known as Motion Estimation (ME) is often applied to reduce the temporal redundancy between successive frames of a video sequence. One of ME techniques, known as Block Matching Algorithm (BMA), has been widely used in various video coding standards. In recent years, many of these BMAs have been developed with similar intention of reducing the computational costs while at the same time maintaining the video signal quality. In this paper, an algorithm called Hexagon-Diamond Search (HDS) is proposed for ME where the algorithm and several fast BMAs, namely Three Step Search (TSS), New Three Step Search (NTSS), Four Step Search (4SS) as well as Diamond Search (DS), are first selected to be implemented onto various type of standard test video sequence using MATLAB before their performances are compared and analyzed in terms of peak signal-to-noise ratio (PSNR), number of search points needed as well as their computational complexity. Simulation results demonstrate that HDS algorithm has speed up other algorithms computational work up to 56% on average while at the same time maintains close performance in terms of average PSNR to others.

BANDSTOP TO ALLPASS RECONFIGURABLE FILTER TECHNIQUE IN SPDT SWITCH DESIGN

In this paper, a bandstop to allpass reconflgurable fllter technique is proposed in Single Pole Double Throw (SPDT) switch design. Proof of concept of the bandstop to allpass reconflgurable fllter is presented. It is physically realized using transmission line and radial stub in 3.5GHz band (3.4 to 3.6GHz). The isolation, insertion loss and return loss of the SPDT switches are analyzed and to validate this technique the prototypes are fabricated using FR4 substrate with a thickness of 16mm. A very good agreement is shown between the simulated and measured results. Using this technique, it is able to produce more than 30dB isolation with minimum number of PIN diodes, thus reducing 42.7% of the total circuit size compared with conventional design. Besides, additional 22.9% of isolation bandwidth can be obtained with the use of radial stub compared with transmission line stub. The potential application of this SPDT switch is Time Division Duplex (TDD) switching for WiMAX and LTE communication system in the 3.5GHz band.

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 Substrate Integrated Waveguide (SIW) bandpass filter based on different method and design

Substrate Integrated Waveguide (SIW) is an emerging technology of high-frequency integrated that appeared in recent years which provides an excellent platform in order to design millimeter wave circuits such as filters, resonators and antennae. It offers advantages in terms of compact size and easy to integrate with the other planar circuit. The fabrication can be done by using standard printed circuit (PCB) where the cost of the manufacturing process will be reduced compared to the conventional waveguide filter. This paper presents the review of SIW bandpass filter for X-band applications for the past few years that have operation frequency from 8.2-12.4 GHz. Most researchers focus on designing SIW bandpass filter rather than other filter because Chebychev filter response is easy to make circuit synthesis. Different types of method have been introduced in the SIW bandpass filter design and the performance of the filter design will be compared.