Modeling and Performance Analysis of Throughput-Received Power Relationship for Indoor Wireless Mesh Network

In Wireless Mesh Network (WMN) the mesh nodes (APs) are configured with the same frequency channel creates a phenomenon called as co-channel interference. The purpose of selecting the same frequency channel is to make sure all the mesh nodes can talk each other within the frequency range. In order to study the effects of this phenomenon together with multipath fading for indoor environment, we have setup a wireless mesh network operating at 2.4GHz inside a 4-floors faculty building. Extensive measurement campaigns have been conducted at each floor. To observe the effects of these phenomena at the application layer perspective, we measure the network throughput and mapped it to the physical layer performance parameter; received power. The relationship between the application and physical layers performance parameters is modeled numerically and the results are analyzed. One interesting finding is that the empirical relationship model for wireless mesh network does not follow the common exponential models as known in Wireless Local Area Network (WLAN). We can say that the throughput drop is too small and can be neglected and the average throughput is at 1.53Mbps over all received powers. The result shows that the effects of both co-channel interference and multipath are very severe and need to be tackled properly in wireless mesh network design and deployment

BAKO : Biodiversity Between Land and the Sea

Sarawak’s vast forested landscape includes numerous protected areas network, comprising National Parks represents some of the best examples of the State’s natural wonders- fl oral, faunal as well as geological. Western Sarawak, in particular, is an important area for biodiversity conservation, being home to many Bornean endemics and other species of conservation importance that do not extend beyond the north-western corner of this large tropical island

Dual Polarization Single Port Inset Feed Microstrip Patch Array Antenna

This paper present the designs of array antenna from type of inset-fed microstrip patch antenna by using single port oriented at 45º and -45º. The antennas are capable to generate dual-polarization radiation pattern centered at 45º and -45º. Combinations of two patches using quarter-wave impedance matching technique has been used to designs the array antennas operate at 2.4 GHz. The designs are simulated using Microwave Office 2004 and were fabricated on FR4 substrate with a dielectric constant εr =4.7, tan δ =0.019 and thickness =1.6mm. The simulation and measurement result have been compared. The 3 design 1x2 array antennas yield a bandwidth greater than 5%. The gain of the proposed antennas is also stable with operated frequency. The result showed that the combination of more patches in array can improve the return loss and gain performances

A Triple-band Dipole Antenna with 0.92 GHz AMC-HIS

A triple-band dipole antenna integrated with 0.92 GHz Artificial Magnetic Conductor (AMC) is presented. The AMC structure is called a highimpedance surface (HIS) structure and is useful as a ground plane to the dipole antenna. This structure can be used to prevent the degradation of tag and antenna performance caused by the conductive materials (metal objects) and to increase the antenna gain. This paper begins by investigating the parameters in AMC design such as a patch and gap size. The AMC is characterized by the frequency where the phase of the reflection coefficient is zero degrees and has reflected wave in-phase with the incident wave

Characterization of electrostatic discharge threshold voltage of phase-shift mask reticle

A reticle is a stencil used in lithography process for forming integrated circuit (IC) on silicon substrate. It consists of a thin (100 nm) coating of masking metallic patterned (features) with critical dimension (CD) of nanometers on a thicker quartz substrate. The features can be damaged by electrostatic discharge (ESD) when exposed to the environment electrostatic charge and caused deformed IC and eventually device difunctional. Semiconductor equipment materials industry (SEMI) standard established the allowable electrostatic charge on reticle based on the characterization of ESD threshold voltage on binary reticle. However, there is another type of reticle which is phase-shift mask (PSM), has not been characterized for its ESD threshold voltage. A direct current (DC) voltage is applied directly to the structures with CD of 80 nm, 110 nm, and 160 nm. The surface current is recorded at all levels of stress from 1 to 100 V. The current–voltage (IV) curve and physical inspection results for each cell are then reviewed and classified. The results yielded which no electric field induced migration (EFM) defect and breakdown voltage occurred at any of the structures. The cathode’s metal work function has been identified as the factor that influences the PSM reticle ESD threshold voltage

INTRODUCTION

The State of Sarawak, with an area of approximately 124,450 km2 , has one of the most established networks of protected areas within Malaysia, representing some of the most megadiverse rainforests of the world. The landscape ranges from coastal lowlands, comprising peat swamps, as well as narrow deltaic and alluvial plains, to a vast hinterland of undulating low hills, that barely reach 300 metres, to the mountainous highlands, that extend to the international border in the interiors of Borneo. The State currently has 67 Totally Protected Areas (including National Parks, Wildlife Sanctuaries and Nature Reserves), scattered throughout the State, a majority located in western Sarawa

A Meandered Triple-band Printed Dipole Antenna for RFID

In this paper, a meandered triple-band printed dipole antenna is proposed for Radio Frequency Identification (RFID). This meandered tri-band printed dipole antenna is designed to operate at 0.92 GHz, 2.45 GHz and 5.8 GHz with the aid of Computer Simulation Technology (CST) software. In order to achieve triple-band operation, the proposed antenna contains two branch elements, which act as an additional resonator. The designed antenna is fabricated using Taconic RF-35 substrate with a dielectric constant (Er) of 3.5 and thickness (h) of 0.508 mm. The antenna’s parameters for triple-band operation are investigated and discussed. Then, this fabricated antenna is integrated with the UHF microchip to become a passive UHF tag. This tag is tested by measuring the reading distance and it is found that the proposed tag can be used for RFID application

Characterization of electrostatic discharge threshold voltage of phase-shift mask reticle

A reticle is a stencil used in lithography process for forming integrated circuit (IC) on silicon substrate. It consists of a thin (100 nm) coating of masking metallic patterned (features) with critical dimension (CD) of nanometers on a thicker quartz substrate. The features can be damaged by electrostatic discharge (ESD) when exposed to the environment electrostatic charge and caused deformed IC and eventually device difunctional. Semiconductor equipment materials industry (SEMI) standard established the allowable electrostatic charge on reticle based on the characterization of ESD threshold voltage on binary reticle. However, there is another type of reticle which is phase-shift mask (PSM), has not been characterized for its ESD threshold voltage. A direct current (DC) voltage is applied directly to the structures with CD of 80 nm, 110 nm, and 160 nm. The surface current is recorded at all levels of stress from 1 to 100 V. The current–voltage (IV) curve and physical inspection results for each cell are then reviewed and classified. The results yielded which no electric field induced migration (EFM) defect and breakdown voltage occurred at any of the structures. The cathode’s metal work function has been identified as the factor that influences the PSM reticle ESD threshold voltage

Intelligent Health Monitoring System (IHMS) Using Wireless ZigBee Technology

In real situation, doctors and health care workers need to move physically from one patient to another patient to perform their duty to check patient’s health condition. This approach to monitor the patient’s health condition continuously is not efficient. Intelligent Health Monitoring System by Using Wireless zigbee (IHMS) is an innovative system that developed to improve the quality of communication among patients, doctors, and other health care workers continuously in real time basis. The IHMS is the integration of wireless zigbee technology and health monitoring using PC/laptop. As PC/laptop has become an inseparable part of our life, thus it can integrate health monitoring more seamlessly to our daily life. The IHMS will identifies/detects the abnormality of the patient and delivery the accurate medical information to the care centre (doctors and health care workers) instantly. Once the abnormality is detected on patient, then the IHMS will react appropriately to collect the patient health information through the sensors and send the alert to care centre and display it in PC/laptop. Furthermore, it is useful to alert the care centre when the patients are not be able to press the emergency call button due to their critical health condition. Thus, the IHMS is developed to enables the doctors and health care workers to monitor the real time health information of their patient and react immediately when abnormality is detected. The IHMS also save the collected patient health information in the database for future reference. The IHMS is helpful for fast emergency response which is crucial for critical case

The Investigation of Polarization Diversity in MIMO System at 2.4 GHz

This paper describes the concept of multiple input multiple output (MIMO) system using polarization diversity that can enhance the channel capacity and increased the data output performance of the system. The microstrip antenna array is designed, fabricated and measured at the desired operating frequency for this measurement. Computer Simulation Technology (CST) software is used to design and simulate the microstrip antenna array. The simulation and measurement data results are compared and discussed. The fabricated microstrip antenna is used to develop the Radio Frequency (RF) MIMO test bed system. The system measurement has been conducted in Microwave Laboratory at Faculty of Electronic and Computer Engineering, University Technical Malaysia Melaka at the operating frequency of 2.4 GHz. The spatial diversity and polarization diversity are applied in measurement campaign to investigate the performance of the wireless MIMO channel. The data obtained from the measurement is processed using MATLAB software in order to calculate the MIMO channel capacity. The analysis has been focused on the effect of the MIMO channel capacity due to the proposed measurement setup configurations. The channel capacity is increased from 0.03 b/s/Hz to 0.09 b/s/Hz when polarization diversity is applied at both transmitter and receive