A.A.H. Azremi

Setup and results of pyramidal microwave absorbers using rice husks

Agricultural wastes are considered not useful and are commonly dumped or burned after crop harvesting. Rice husks from paddy (Oryza sativa) are example of agricultural wastes. Rice husks have been investigated as the material for the pyramidal microwave absorbers. The setup for the fabrication and measurement of the rice husks pyramidal microwave absorbers are discussed. An 8£8 array of pyramidal microwave absorber using the rice husks-polyester-MEKP mixture has been designed and fabricated. There are four main stages in this work: the collection of the raw rice husks materials, the mould fabrication, the pyramidal microwave absorber fabrication and the experiments performed to determine the re∞ection loss performance of the rice husks pyramidal microwave absorbers. Experimental

Performance Simulation of Pyramidal and Wedge Microwave Absorbers

Anechoic chambers signal absorption capability is directly correlated to its performance. One of the main components in enabling signal absorption is the design and material used in designing the absorbers. Two of the main types are pyramidal and wedge-shaped ones. In this work, truncated pyramidal and truncated wedge absorbers for anechoic chamber application have been designed to operate effectively in the microwave frequencies from 1 - 10 GHz. The absorbers were simulated using a fusion of carbon-based material with different features and coating thickness to improve their performance and significant material cost savings. Material consideration for the basic pyramidal and wedge structure has also been taken into account. The designs are simulated using CST Microwave Studio. Simulated results showed that the coating of half the absorber height produced the best performance in terms of signal absorption.

Effect on source signal condition for pyramidal microwave absorber performance

In designing a microwave absorber for anechoic chamber, there are many condition can affect the performance of microwave absorber. In this work, four conditions are discussed to compare the reflectivity or S11 of the pyramidal microwave absorber. The conditions are different signal source position, areas, angle, and lastly the distance between signal source and pyramidal microwave absorber. These pyramidal microwave absorber are simulated in CST Microwave Studio by using the rice husk as it based material that have dielectric constant, εr = 2.9. This absorber has been designed to operate effectively in frequency range of 1 GHz to 20 GHz

Preliminary development of mini anechoic chamber

The purpose of mini anechoic chamber is to allow cost effective testing of microwave signal. It is because measurements of the radiation pattern are usually done in an anechoic chamber in order to avoid reflections from nearby objects and external interference from affecting the field pattern. The most important element in anechoic chamber is absorber. The electromagnetic wave absorbers are used to absorb the reflected wave that occurs on the wall of the chamber. A good absorber is the one with smaller reading of reflection wave. The operation of absorber depends on the design and the material used. This project focused on the development and designs the absorbers for anechoic chamber. There were then assembled into a chamber for further testing.

A development of Fractal PIFA (planar inverted F antenna) with bandwidth enhancement for mobile phone applications

A novel Fractal planar inverted F antenna (F-PIFA) based on the self affinity design is presented in this paper. The procedure for designing a Fractal Planar Inverted F Antenna is explained and the 2nd iteration of Sierpinski Carpet is chosen to use in mobile phones. The F-PIFA has a total dimension 27mm × 27mm are designed and optimized in order to receive GSM (Global System for Mobile Communication) and UMTS (Universal Mobile Telecommunication System) and HiperLAN (HigH Performance Radio LAN with the frequency range from 1710 MHz to 2170 MHz, 1885 to 2200 MHz for 3G and 4800MHz to 5800MHz for HiperLAN respectively. The antenna achieved the GSM, UMTS and HiperLan frequency with −6dB return loss and has almost omnidirectional radiation pattern. This antenna has been tested using mobile phone model and all the performance met the criteria for a mobile phone application.

A parametric study of broadband Planar Inverted F antenna (PIFA) for WLAN application

A novel of comprehensive study and useful information for the design of broadband planar inverted F antenna (PIFA) is proposed. The antenna including the ground plane has a total dimension 6 mm times 70 mm times 30 mm has been optimized to be operating within WLAN application standards. The size of this antenna makes it ideally suitable for handheld wireless communicators. The physical parameters of the antenna, including shorting plate width, antenna height and ground plane dimensions, are studied. The influence of various parameters on antenna characteristics has been investigated using simulation software tool. By understanding the effect of each parameter, a novel comprehensive study for a better design of broadband PIFA is proposed. These results are very useful in the design of PIFA.

A dual band planar monopole antenna with inverted-M parasitic plane

Introduction of parasitic plane as additional radiator helps to produce desired resonant frequencies, while helping to minimize the size of the antenna. A dual-band monopole antenna with parasitic plane is designed to satisfy dual-band applications, namely UMTS and WLAN 802.11. This work is an effort to investigate the effect of employing an inverted M-shaped parasitic plane, which introduces double slits in the monopole structure. The antenna parametric analysis of the antenna configuration was performed using experimental method. Results simulated and measured shows good correlation and the antenna is verified to be working in a dual band mode.

Multiband Fractal PIFA (Planar Inverted F Antenna) for mobile phones

A novel Fractal planar inverted F antenna F-PIFA) based on the self affinity design is presented in this paper. The procedure for designing a Fractal Planar Inverted F Antenna is explained and the 2nd iteration of Sierpinski Carpet is chosen as an antenna for mobile phones. The F-PIFA has a total dimension of 27 mm × 27 mm and is designed and optimized to receive GSM (Global System for Mobile Communication) and UMTS (Universal Mobile Telecommunication System) and HiperLAN (High Performance Radio LAN). The frequency ranges are from 1900 MHz to 2100 MHz, 1885 to 2200 MHz for 3G and 4800 MHz to 5800 MHz for HiperLAN respectively. The antenna covered the GSM, UMTS and HiperLan frequency ranges with −6dB return loss and has an almost omni-directional radiation pattern. This antenna has been tested using a mobile phone model and the performance met all the criteria for a mobile phone application.

A cylindrical barium strontium titanate (BST) dielectric resonator antenna for 5.0 GHz wireless LAN application

This paper presents a dielectric resonator antenna (DRA) suitable for wireless communication applications at 5.0 GHz. The proposed DRA utilizes a ferroelectric material, Barium Strontium Titanate (BST) in cylindrical form with dielectric constant of epsivr = 250. The antenna is fed with 50 Omega microstrip transmission lines. The physical parameters of the antenna, including radius (r), height (h), position (p) of BST, and ground plane dimensions, are studied. The influence of various parameters on antenna characteristics has been investigated and optimize by extensive numerical simulations by Microwave Studio, Computer Simulation Technology (CST) package. By understanding the effect each parameter, a better design of DRA producing desired bandwidth and frequencies can be accomplish. The size of this antenna makes it ideally suitable for handheld wireless LAN communicators.

Design of a microstrip patch antenna using Low Temperature Co-Fired Ceramic Technology

This paper presents the design of a single rectangular microstrip patch antenna for operation at 2.4 GHz frequency on Radio Frequency (RF) antenna application using low temperature co-fired ceramic (LTCC) technology. LTCC is chosen as the substrate because of compactness and or being light-weight. It also offers high-speed and functionality for portable electronic devices used for wireless voice and data communication in rapidly expanding mobile network systems. The aim of this project was to design and simulate a microstrip patch antenna on the LTCC substrate call Ferro A6M tape operating at 2.4 GHz. Two microstrip patch antennas operating at 2.4 GHz was designed, and simulated; a rectangular microstrip patch antenna using LTCC technology has a length, L, 25.5 mm and a width, W, 34 mm and a rectangular microstrip patch antenna using printed circuit board (PCB) technology has a length, L, 28 mm and width, W, 37 mm. Those designs were simulated with Microwave Office software.