Norshafinash Saudin

The Use of a Human Body Model to Determine the Variation of Path Losses in the Human Body Channel in Wireless Capsule Endoscopy

Presently, wireless capsule endoscopy (WCE) is the sole technology for inspecting the human gastrointestinal (GI) tract for diseases painlessly and in a non-invasive way. For the further development of WCE, the main concern is the development of a high- speed telemetry system that is capable of transmitting high-resolution images at a higher frame rate, which is also a concern in the use of conventional endoscopy. A vital task for such a high-speed telemetry system is to be able to determine the path loss and how it varies in a radio channel in order to calculate the proper link budget. The hostile nature of the human bodys channel and the complex anatomical structure of the GI tract cause remarkable variations in path loss at difierent frequencies of the system as well as at capsule locations that have high impacts on the calculation of the link budget. This paper presents the path loss and its variation in terms of system frequency and location of the capsule. Along with the guideline about the optimum system frequency for WCE, we present the difierence between the maximum and minimum path loss at difierent anatomical regions, which is the most important information in the link-margin setup for highly e-cient telemetry systems in next-generation capsules. In order

Complementary structure of quadruple P-spiral split ring resonator (QPS-SRR) on modified Minkowski patch antenna design

In this work, a modified Minkowski patch antenna had been designed for 2.4 GHz of resonant frequency, fr for wireless local area network (WLAN) application. The proposed complimentary structure of quadruple P-spiral split ring resonator (QPS-SRR) into the patch antenna had been increasing the gain performance. Other parameters that had been considered in this work are return loss, bandwidth, radiation pattern and directivity. This paper also discussed on the effect of single, double and triple sets of quadruple P-shape of the Minkowski patch antenna. This Minkowski patch antenna potentially can be operating the frequency range between 2.362 GHz to 2.427 GHz with a resonant frequency at 2.394 GHz and bandwidth of 65 MHz. The return loss of this Minkowski patch antenna is - 26.072 dB at frequency of 2.4 GHz while the gain is 2.555 dB at frequency of 2.4 GHz.

Modified cuckoo search algorithm in weighted sum optimization for linear antenna array synthesis

In this study, we proposed a bio-inspired technique known as modified cuckoo search (MCS)-based weighted sum algorithm towards synthesizing symmetric linear array geometry with minimum side lobe level (SLL) and/or nulls control. The newly evolved metaheuristic algorithm was primarily based on the natural obligate brood parasitic behavior of some cuckoo species in combination with the Lévy flight behavior of some birds and fruit flies. Through the integration with the Roulette wheel selection operator and the inertia weight controlling the position (solution) exploration, the MCS-based weighted sum approach optimized concurrently the array element excitation locations, amplitudes, and phases within the uniform pattern and Dolph-Chebyshev window, respectively. The optimal solutions obtained were then compared against the conventional (with λ/2 inter-element distance) and other chosen evolutionary algorithms-based arrays.

Effect of different substrate materials on a wearable textile monopole antenna

In this paper the investigation of the effect using different substrate materials on a textile monopole antenna is discussed. This textile monopole antenna is designed to be used for Body-Centric Wireless Communications (BCWC) at 2.45 GHz. Three types of non-conductive materials were selected: felt, fleece and foam. The textile monopole was benchmarked against a conventional FR-4 monopole antenna. The results demonstrated a good agreement between simulated return loss of all three substrates used for textile monopole antenna and conventional monopole antenna. The felt-based textile monopole antenna offered higher return loss compared to other substrates and conventional monopole antenna. Moreover, the substrate materials gained bandwidths of up to 1000 MHz in free space where fleece fabric produced broader bandwidth compared to other substrates. The simulated gain characteristics for all three types of substrates agreed reasonably well with conventional monopole antenna.

Investigation of sugar cane bagasse as alternative material for pyramidal microwave absorber design

Sugar cane bagasse as is potential agricultural waste to produce an alternative and beneficial product for any suitable application such as pyramidal microwave absorber for anechoic chamber testing application. In this work, the dielectric properties (dielectric constant and tangent loss) of the sugar cane baggase had been measured using the dielectric probe measurement. The sugar can bagasse pyramidal microwave absorber had been modelled and simulate in the CST Microwave Studio using the data from the dielectric probe measurement. This pyramidal microwave absorber had been operating in the microwave frequency range between 0.1 GHz to 20.0 GHz. The targeting reflection loss of this pyramidal microwave absorber is better than - 30 dB. The reflection loss performance comparison with the rice husk also had been done in this work.

Design of Ground Penetrating Radar antenna for buried object detection

In this paper, the design of planar antenna for use in Ground Penetrating Radar (GPR) for buried object detection is presented. The proposed antenna offers wide operational bandwidth within 500 MHz to 2 GHz frequency band. This property makes the antenna suitable for the application of GPR for buried object detection. Taconic TLY-5 is used as the substrate with dielectric constant of 2.2, tangent loss of 0.0009 and thickness of 1.57 mm. The proposed antenna has simple structure and fully planar, therefore it is easy to integrate with other planar devices. To obtain a directional radiation pattern, the antenna is placed inside an open metallic shielded box. In turn, the gain of the antenna is also increased using this approach. The results in term of reflection coefficient, gain, radiation pattern of the antenna are discussed in this paper.

Potential of dried banana leaves for pyramidal microwave absorber design

Abandoned agricultural waste pose a risk to the environmental and public health. The polyurethane and polystyrene material for designing pyramidal microwave absorber are expensive and not environmental friendly. Tropical crop residue has potential to be used in the electromagnetic testing area. Nowadays, electromagnetic absorbing materials have been increasingly important in ensuring successful Radio Frequency (RF) anechoic chamber testing performance. New material had been research to reduce the cost of designing pyramidal microwave absorber. In this case, dried banana leaves are mixed with polyester and methyl ethyl ketone peroxide (MEKP) to give the best reflection loss performance to the pyramidal microwave absorber compare to the previous research using rice husk. This pyramidal microwave absorber is operating in the frequency range from 0.1 GHz to 20.0 GHz.

A Simple Technique for Improving the Anechoic Performance of a Pyramidal Absorber

In this paper, we propose a very simple technique that ofiers an extra degree of freedom to optimize the design of a tire dust- based absorber with reduced height. Cladding is a technique that is used to enhance the surface properties of a part, and it has been used in many applications for many years. In this technique, a clad layer is created on the core material, and the composition of the clad layer is adjusted to enhance the performance of the core material. We use a rice husk-clad layer to enhance the impedance matching characteristics of the low-loss, tire-dust core, microwave absorber. The overall design is a two-layer, geometrically-tapered, pyramidal structure composed of two lossy waste materials. Our main goal was to make the front surface less re∞ective (impedance matched), hence the material of the outer layer (clad) of the absorber was selected on the basis of the analysis of the dielectric properties of the candidate materials. Optimum thickness of the clad was obtained by using CST simulation software and found to be 12mm, for which a re∞ectivity performance of less than i20dB was

Frequency selective surface for enhance WLAN applications

This paper proposes the deployment of frequency selective surface (FSS) structure in WLAN device. Objectives to create a band pass square-loop filter FSS in WLAN device to increase the received signal strength of WLAN signal 2.4GHz. FSS works to enhance the 2.4 GHz signal and attenuate the rest signal other than 2.4 GHz. The WLAN signals increasing more than 50 % when pass through the FSS structure.

Ground penetrating radar: Antenna for buried object detection

In this paper, the design of wideband antenna with half and defected ground plane for buried object detection is presented. The antenna offers wide bandwidth from 0.5 GHz up to 3 GHz which is suitable for ground penetrating radar (GPR) system to detect buried objects under the ground surfaces. The simple structure and easy to integrate with planar substrate are the advantages of the antenna. A rectangular reflector is placed at the back of the antenna to obtain unidirectional radiation pattern which make it suitable for use in GPR system. The results such as return loss, gain and radiation pattern of the antenna are discussed in this paper.