Norun Abdul Malek

3D reconfigurable antenna

A simple programming technique (MATLAB) has been written for the analysis of a beam reconfigurable antenna array. The technique is based on the calculation of mutual impedance using Induced EMF method. This can be applied to an array of dipoles arranged in various configurations. An array of 12 dipoles has been positioned at the edge of a cube structure to demonstrate this behaviour. The size of the cube is (0.6533λ0)3 m3. Beams may be focussed in different directions by turning On (feeding) one or more dipoles while the rest remain short-circuited (Off). The results match with simulation software such as NEC and EMPIRE XCcel.

An Improved Image Steganography algorithm based on PVD

Zarina Mohd Noh*, Abdul Rahman Ramli, Marsyita Hanafi, M Iqbal Saripan, Ridza Azri Ramlee 1,2,3,4 Department of Computer and Communication Systems Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia 1,5 Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 75450 Durian Tunggal, Melaka, Malaysia

Robust vision-based multiple moving object detection and tracking from video sequences

Zarina Mohd Noh*, Abdul Rahman Ramli, Marsyita Hanafi, M Iqbal Saripan, Ridza Azri Ramlee 1,2,3,4 Department of Computer and Communication Systems Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia 1,5 Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 75450 Durian Tunggal, Melaka, Malaysia

Development of wearable patch antenna for medical application

This paper presents the development of a flexible antenna made of Polydimethylsiloxane (PDMS) and Copper (Cu) patch. The antenna comprises of Cu tape as the patch and ground plane, PDMS composite as the substrate and SMA connector as the coaxial feed with dimensions of 21.5mm patch radius, 60×60×3 mm3 substrate area and 60×60 mm2 ground plane area. In this study, we also create a PDMS+glass microsphere composite as substitute to the PDMS substrate. The PDMS+glass inclusion reduces PDMSs relative permittivity and loss tangent to 1.9 and 0.014 respectively which could enhance antennas performance. To overcome adhesiveness issue between Cu patch and PDMS substrate, the antenna was encapsulated with another thin layer of PDMS/PDMS+glass substrate of 0.6mm thickness to ensure a constant distance from the ground plane. CST software was used to simulate antenna resonance frequency prior to the fabrication. Measurements using a Vector Network Analyzer (VNA) showed that the PDMS substrate antennas resonated at 1.92 GHz (without encapsulation) and 2.34 GHz (with encapsulation) while the PDMS+glass substrate antennas resonated at 2.46 GHz (without encapsulation) and 2.25 GHz (with encapsulation) respectively. Here, we also discussed the effect of substrate on return loss. Overall, results obtained from the measurements are in agreement with the simulation results.

Design of a Circular Patch Antenna for 3D Printing

This paper proposes an innovative circular patch antenna that resonated at 2.34 GHz using 3D printing technique. The purpose of using 3D printing is a way to reduce cost and time in fabrication of the antenna. By introducing a new material to the subject which is Acrylonitrile Butadiene Styrene (ABS) as the substrate of the antenna, the cost can be greatly reduced. Furthermore, a coaxial probe feed is used and it is said to be easy to fabricate, matched and has low spurious radiation. The feeding method that has been used in this research is a coaxial line feed where the inner conductor of the coax is connected to the patch meanwhile the conductor is connected to the ground. This antenna is designed on an ABS substrate with εr = 2.74 and it has a loss tangent of 0.007. The thickness is said to be 3.25 mm. In addition to that, it has the return loss (S11) of 24.3 dB at 2.34 GHz. The whole designation of the antenna is by using Computer Simulation Technology (CST) software. The anticipated design of a circular patch antenna can be extended to conformal antenna and therefore, the prototype will become more compact, efficient and robust.

Mitigation technique for rain fade using frequency diversity method

The radio waves propagating through the earth atmosphere is attenuated due to the presence of atmosphere particles, such as water vapor, water drops and the ice particles. The atmospheric gases and rain both absorb and scatter the radio waves, and consequently degrade the performance of the microwave link. Millimeter wave (mmWave) is todays breakthrough frontier for emerging wireless mobile cellular networks, wireless local area networks, personal area networks, and vehicular communications. In the near future, mmWave products, systems, theories, and devices will come together to deliver mobile data rates thousands of times faster than todays existing cellular and WiFi networks for an example from the era of 3 G towards 5 G mobile communication near future. However for Tropical countries the data link realibility is effected during rain. Rain is a major source of attenuation for microwave propagation above 7 GHz [1], In tropical and equatorial regions, the rain intensity is higher and designing terrestrial and earth-to-satellite microwave links are very critical and challenging for high frequencies. This paper presents the summary of rain effects studies for lower operating frequency such as C band compare to higher operating frequency such as Ka band in tropical environment The main objective is to justify the literature findings on the effect of rain at lower and higher operating frequency in microwave link and solution to overcome it by implementing Switching Circuit as Fade Mitigation Technique (FMT). An experimental test bed has been set up for 5.8 GHz and 26 GHz terrestrial point to point data communication link. The received signal strength (RSS) data and rain fall intensity data were recorded for 24 hours daily over period of 12 months (Jan 2013-Dec 2013) at 1 minute interval. The collected rain rate data has been analyzed with some prediction models. The main outcome of the research shows that there is negligible effect of rain for 5.8 GHz link whereas it very strong on the 26 GHz link. It was observed 15 dB to 35 dB attenuation during measurement period. The FMT used in this research for dual frequency by shifting the operating frequency to lower band (5.8 GHz) while heavy rain and shifting back to normal position at higher operating frequency (26 GHz) using the threshold level as reference seems to be one of the solution in future. This findings will be useful resources of information for researchers or telecommunication engineers.

Beam steering of four dipoles antenna array using genetic algorithm

This paper demonstrates the capability of four dipoles antenna (two-dimensional array) to steer the beam to arbitrary direction. A combination of genetic algorithm and array analysis based on the Induced EMF method optimised the input excitation of each dipole to maximise the main lobe to any azimuth direction. The optimisation is performed using MATLAB software. The Induced EMF method incorporates the mutual coupling between dipoles giving more accurate results in comparison with pattern multiplication method. The results show that the beam steering of a phased array antenna in two dimensions may be achieved using a genetic algorithm.

Development of spectrum monitoring tool for Malaysia

Rapid growth on new technologies and services in mobile communication leads to stronger competition in spectrum access. As a developed country, Malaysia is also affected by this trend. With the increasing numbers of subscribers, the easier solution for mobile service providers to improve the coverage area is by installing new base station (BS). Nevertheless, this increases the possibilities of interference among BS. Thus, spectrum monitoring is needed to maintain the efficiency of the network and avoid interference. However, the commercial spectrum monitoring tool is not a cost effective enough in the fast pace changing mobile communication environment. Hence, the need for development of a low cost radio frequency (RF) spectrum monitoring tool to identified and monitor interference. This paper aims to highlight the approaches taken in developing an open-source spectrum management tool for Malaysian authority. The simple low cost tool is capable to identified possible interference among BS in Global System for Mobile Communications (GSM), 2G and Universal Mobile Telecommunications System (IMT), 3G networks as well as capable to display BS cell coverage area.

Pattern synthesis using combination of the Induced EMF Method and a Genetic Algorithm

This paper presented pattern synthesis using the Induced EMF Method and a Genetic Algorithm (GA). A cosine shaped main beam has been chosen as desired pattern. This technique is suitable for 3D antenna arrays where the position of each element is in various configurations. For 700 generations and penalty constant is 0.05, the GA converges rapidly until it reaches 200 and remains constant at 0.79. This value represents the comparison between desired and optimised radiation pattern.