Liew Hui Fang

Determination of Dielectric Properties of Bismuth Titanate (BiT) Ceramic Material for WiMAX/WLAN Antenna

The utilization of Bismuth Titanate (BiT) as a ceramic material on an antenna has been investigated. The BiT ceramic material is of interest for a range of Wireless Local Area Network (WLAN) IEEE 802.11 b/g and Worldwide Interoperability for Microwave Access (WiMAX) IEEE 802.16 application, which covers the range of 2.3 GHz to 2.5 GHz. The BiT ceramic material had been tested to own a high dielectric constant of εr= 15 that is able to miniaturize an antenna. There is a high demand nowadays on the miniature antenna for smaller devices. An experimental prototype at WiMAX/WLAN range was built and measured on its dielectric properties, especially the dielectric constant and dielectric loss of the prototype material.

A review of techniques design acoustic energy harvesting

This paper presents a study of recent development in the field of acoustic energy harvesters (AEHs) technique and the maximum power generated from each of these techniques. AEHs convert the acoustic energy into useful electrical energy for the operation of autonomous wireless sensors. Acoustic energy is an important form of efficiency energy which is created and unused all around us. Due to the majority of acoustic energy a main challenge of energy harvesting is the low power density in typical acoustic noise fields. With a superior emphasis on green energy, acoustic energy is one of the enormously existing energy sources and so harvesting this energy plays an significant role in research. Since acoustic energy is environmentally friendly and sufficient to replace as disadvantages of conventional battery which have limited lifespan and problematic in electronics could expire at any time and replacement of the battery causing some cost and time. The induced acoustic wave can be transformed into electricity by presenting novel environment friendly energy converters.

Review Compact Microwave Filter for Harmonic Rejection

An investigation of the several different techniques and method have been suggested in the design of compact microwave filters for the realization of high performance output micromachined microstrip low pass filters and highest attenuation loss is presented in this paper. It is shown that the basis for much fundamental microwave filter theory lies in the real of lumped-element filters, which lumped elements suffers for not suitable use in high frequency, because wavelength will decrease to short and the only distributed elements can practically well and the lumped elements circuit and work efficiently at low frequency or vice versa wavelength of distributed elements become too larger. In this paper, a review of numerous methods of design compact microstrip filters that have been offered over the last years is proposed, including a discussion of topologies and the structures used to make compactness size of microwave filters.

Conversion of UHF Composite Low Pass Filter into Microstrip Line Form

This paper presents the design of a compact, composite, low-pass filter circuit into micro strip line form using a new, transforming method. The composite, low-pass filter operating in the UHF range were designed and implemented on an FR4 substrate. The circuits were simulated and developed using Advanced Design Software (ADS) for both lumped element and micro strip filters. A correction factor was considered due to fringing inductance and capacitance. The ADS simulation results showed that the response of the micro strip line circuit of the composite, low-pass filter with fringing correction factor was well agreement with its lumped circuit. This showed that the new transforming method enabled to the lumped element circuit into a micro strip line to solve the complex design of composite filters.

On the Miniaturization High Permittivity DRA with Array Patches

The miniaturization on planar printed-circuit antennas by loading the ceramic material of high permittivity material bismuth titanate has been experimentally demonstrate on the micro strip patch antenna. Due to its very small size and radiation performance, it is compatible for packaging constraints and can be easily integrated in a big variety of portable devices. The results show that the size reduction is achieved with the gain of the ceramic material antenna comparable with that of conventional micro strip antenna. In this paper, the miniaturized antenna array technology with high permittivity ceramic material, bismuth titanate array antenna is described, along with comparison computer simulation results with conventional micro strip patch antenna.