Rosemizi Abd Rahim

A 2.45 GHz circular patch antenna with harmonic suppression for wireless power transmission

This paper proposed a new circular patch antenna design with harmonics suppression capability. The purpose of harmonic suppression antenna is to eliminate the use of harmonic filter circuit in rectenna circuit. By introducing slits at the antenna patch and stub at the transmission line, unwanted harmonics frequencies are successfully suppressed. In addition, the size of proposed circular patch antenna is reduced by using partial ground and circular slot technique at the ground plane. The patch antenna is design on FR4 substrate with εr=4.7 and a thickness of 1.6 mm has −48dB return loss at 2.45GHz and suppress the second and third harmonic up to −3dB. The proposed harmonic suppression antenna can be applied in rectenna and active integrated antenna (AIA) applications, thus the circuit become compact, cheaper and more efficient.

A 2.45 GHz harmonic suppression rectangular patch antenna

This paper presented a new design of rectangular patch antenna which is able to suppress the harmonic frequencies. The techniques that are used in the suppression of harmonics are a notch-loaded and curvature slots at the antenna patch together with an open stub and inset feed transmission line. The partially ground with a circular slot at ground plane is also introduced to reduce the overall patch size. The patch antenna is designed on an FR4 substrate with εr=4.7 and a thickness of 1.6 mm give -40dB return loss at 2.45GHz and suppress all the harmonics up to -1dB. The proposed of harmonic suppression antenna can avoid by using harmonic filter circuit in the rectenna circuit and active integrated antenna (AIA) applications, thus the system becomes compact and cheaper.

Modeling and simulation of variable weight zero cross correlation code in optical access network

In this paper, we demonstrate a novel architecture of variable weight Zero Cross Correlation code in the family of Spectral Amplitude Coding(SAC) Optical Code Division Multiple Access (OCDMA) to be utilized in the triple play services of OCDMA applications based on the end users demand and requirements. This is achieved by adapting multiple weights of Zero Cross Correlation (ZCC) code onto one system to accommodate different Quality of Service (QoS) requirements. The results are characterized by bit error rate (BER) and eye pattern simulated using OptiSystem software. Results proved a successful transmission of this scheme over 20km distance thus offering flexibility of independent QoS. It is also revealed that the performance is always better for users with larger number of code weight compared to those assigned with smaller code weight.

An investigation of ambient radio frequency as a candidate for energy harvesting source

In this paper, a feasibility study of the ambient radio frequency (RF) as an energy source to be harvested and converted into electrical energy is presented. This study is to investigate the ability to harvest the ambient RF power density produced by the GSM telecommunication tower for very low power device usage. To capture the RF signal, a normal mode helical rectenna is designed and fabricated. The reason of choosing the normal mode helical antenna in this study is to solve the major problem of a microstrip patch antenna array where the overall size is very large. Experimental results showed that with -10dBm input power, a voltage of 0.3V is generated at the distance 2.5 meters. Hence, this proved that the ambient RF energy can be a suitable candidate as an energy harvesting source.

Harmonics suppression circular polarization elliptical shape microstrip patch antenna

This paper proposed a new design of a 2.45 GHz harmonic suppression circularly polarized microstrip patch antenna. The purpose of harmonic suppression antenna is to eliminate the using of harmonic filter circuit in a rectenna system as well as for the others active integrated antenna (AIA) applications. By introducing a defected ground structure (DGS) technique with a back-to-back U shape slot, the magnitude of the return loss at the harmonic frequencies are suppressed successfully. The patch antenna is designed on an FR4 substrate with εr=4.7 and a thickness of 1.6 mm have -28dB return loss at 2.45GHz and suppress the second and third harmonic up to -0.8dB and -1.8dB respectively.

Hybrid subcarrier multiplexing Wavelength Division Multiplexing using laser and LED spectral slicing architecture

This paper demonstrates a novel architecture of hybrid subcarrier multiplexing Wavelength Division Multiplexing network combining laser and light emitting diodes (LED) as the light sources. The performances are simulated using Optisys software and analyzed based on bit error rates (BER) and the eye pattern of the received signals. Results proved that the combination of the laser and LED light sources in one system can be considered an effective way to maximize system capacity and at the same time, reduce implementation cost of hybrid SCM WDM network architecture.

Performance of hybrid subcarrier multiplexed — optical CDMA system based on different detection methods

In this article, a subcarrier-multiplexed Optical CDMA system utilizing the direct and AND subtraction method in receivers detection is explored. The OCDMA part exploits the Recursive Combinatorial (RC) code for its algorithm. The two different designs are then simulated and the performances are compared. Results indicate that the hybrid SCM/OCDMA system using direct detection technique could transmit to a longer distance of up to 50 km with better quality than that with AND subtraction detection for acceptable communication error rate of BER of 10-9.

State-of-the-Art Developments of Acoustic Energy Transfer

Acoustic energy transfer (AET) technology has drawn significant industrial attention recently. This paper presents the reviews of the existing AETs sequentially, preferably, from the early stage. From the review, it is evident that, among all the classes of wireless energy transfer, AET is the safest technology to adopt. Thus, it is highly recommended for sensitive area and devices, especially implantable devices. Though, the efficiency for relatively long distances (i.e., >30 mm) is less than that of inductive or capacitive power transfer; however, the trade-off between safety considerations and performances is highly suitable and better than others. From the presented statistics, it is evident that AET is capable of transmitting 1.068 kW and 5.4 W of energy through wall and in-body medium (implants), respectively. Progressively, the AET efficiency can reach up to 88% in extension to 8.6 m separation distance which is even superior to that of inductive and capacitive power transfer.

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.

Microstrip dual-band bandpass filter for ISM band applications

This paper presents a development of microstrip dual-band bandpass filter for Industrial, Scientific and Medical (ISM) band application. The proposed bandpass filter which can operate at 2.4 GHz and 5 GHz band is implemented based on parallel coupled line technique. The parallel coupled line filter allows tuning two bands at desired frequencies apart for minimizing the return losses within both dual passband. The Advanced Design System (ADS) simulator has been used during simulation and optimization. For the design verification, the prototype of the proposed microstrip filter has been fabricated and measured. The simulated return loss S11 and insertion loss S21 of the proposed microstrip filter are -25.092 dB and -0.013 dB at 2.4 GHz respectively, while -22.373 dB and -0.025 dB at 5 GHz respectively. For the design verification, the prototype of the proposed antenna was fabricated and measured. The result shows that the proposed design can be realized in any communication system applications.