Aziati H. Awang

GSM activated watering system prototype

it is a challenge to maintain soil moisture for plants. Current watering system offered scheduling scheme as the solution, which might cause the soil to be too wet during the rainy seasons and too dry during the draught season. This prototype uses Arduino Uno R3 board which is easy to program and economical. It is programmed in such a way that it will sense the moisture level of the soil and supply the water if required. This type of system is often used for general plant care, as part of caring for small and medium orchard for small and medium enterprise (SME). Therefore, the microcontroller has coded the system to water the plants according to the reading from the moisture sensor which has been calibrated. On top of that, this system is extended using GSM technology, which enables the user to control the motor by sending and received the SMS (Short Message Service). So, by sending a SMS the user can look after his farm remotely. An easy access to the watering system using GSM technology is what the prototype offers.

Parametric Study of Integrated Stacked Microstrip Antenna with Light Emitting Diode (LED) for Wi-Fi Application

In this paper the parametric study of integrated rectangular stacked microstrip antenna with Light Emitting Diode (LED) for Wi-Fi application is presented. There are two objectives in this design: one is the analysis of when the LED placed at difference layer from the radiating patch, another one analysis is by looking at the electrical connection of 18 LEDs in series, parallel and a combination of series and parallel. The antenna was simulated design and optimized at 2.45 GHz using Computer Simulation Technology (CST) with permittivity, εr = 4.5 and thickness, h = 1.6mm on FR4 substrate. The LED placed on the top substrate as the parasitic element. The radiating patch is placed at the second layer of substrate and aperture coupled feeding network was used in this design. The antennas are reasonable well matched at their corresponding frequency of operations. The simulation results have shown that the antenna works well.

Investigation of mutual coupling effect between five-element arrays of half cylindrical DRAs

The aim of this paper is to investigate the effect of mutual coupling between five-element arrays of half cylindrical DRAs at resonance frequency of 5.9099 GHz. The design of DRAs will be investigated using powerful electromagnetic fields simulation software called CST Microwave Studio/spl trade/. A single half cylindrical DRA was designed and simulated using Microwave Studio. The results were verified with the simulation result using FDTD. In Microwave Studio, to perform the field simulation it utilises finite integration method (FI-Method) with perfect boundary approximation/spl trade/ (PBA). Results obtained from Microwave Studio simulation were compared with finite difference time domain (FDTD) simulation. A good agreement between the two simulated results was obtained. The performance comparisons were focussed on near and far field distribution and the bandwidth. From single cylindrical DRA, the structure was extended into five-element arrays. The result found that in TE/sub 01/spl delta// mode, placing the DRA side by side to each other has the risk of mutual coupling and interference. It was demonstrated that the levels of mutual coupling between the DRAs are very high when they are placed with a spacing of /spl lambda//2 between each other, thus isolation between DRAs along the length of an array is low. The level of mutual coupling between them is significant in terms of return loss and E-field distribution. The level of mutual coupling becomes weaker when the DRA is further away from the excited port.

Comparative analysis for multilayer stacked substrates microstrip patch antenna

the comparative analysis for multilayer stacked substrates microstrip patch antenna has been study in this paper. The analysis is carried out to investigate the effect of adding a difference thickness substrate into antenna design for indoor application. An aperture slot feeding technique is used to provide wider bandwidths, and better isolation between antennas and the feed network. The analysis will focusing with two objective, one is to find out the structure that can maintain the antenna resonant frequency and the second objective is to increase antenna thickness by stacking substrate at difference layer from the radiating patch that hope can improve antenna performance. The antenna was simulated design and optimized at 2.45 GHz using Computer Simulation Technology (CST) with permittivity, εr = 4.3 and thickness, h = 1.6mm on FR4 substrate. The third substrate placed on the top antenna structure to improve antenna performance. The radiating patch is placed at the second layer of substrate and aperture coupled feeding network was used in this design. The antennas are reasonable well matched at their corresponding frequency of operations. The simulation results have shown that the antenna works well.

Design of a SIW-Based Microstrip Diplexer Using TM010 Circular Cavity

This paper describes the application of a Substrate Integrated Waveguide (SIW) for the design of a microstrip diplexer. The diplexer is composed of two SIW circular cavity filters designed individually and combined together using a T-junction with center frequencies at 2.4 and 2.6 GHz, respectively. The working mode for the circular cavity structures is TM010 mode. To prove the concept, the diplexer is fabricated using Rogers RT5880 with dielectric constant, \( \varepsilon_{r} \) = 2.2 and height of substrate 1.57 mm. The performances of the proposed design are verified through both simulation and measurement.

Integration Diamond Shape Antenna with SMD Light Emitting Diode

This paper present an investigation on integration diamond shape antenna with the Surface Mount Device (SMD) Light Emitting Diode (LED). The parameters of the antenna are determined using basic square antenna equations. Numerical simulation is carried out using CST Microwave Studio 2014 and fabricated on the FR-4 substrate. The performances of the integrated antenna were investigated and compared through simulation and measurement in term of the return loss, resonant frequency, gain, radiation pattern and VSWR. By having integrated LED and radiating patch, the frequency is shifted to the lower frequency and the return loss shows well-matched. It also verified that LED is acts like a bridge connected the radiating patch with parasitic loop.

First order diplexer using SIW-based circular cavity resonator

A design of Substrate Integrated Waveguide (SIW) diplexer is proposed. The diplexer is formed using two SIW circular cavity resonators designed individually and combined through a T-junction. The circular cavity structure using TM010 mode is employed in the design of this diplexer. To prove the concept, the diplexer is fabricated using Rogers RT5880 with dielectric constant, □r = 2.2 and height of substrate 1.57 mm. The diplexer is fabricated with standard printed circuit board technology and will be operating at 2.4 GHz and 2.6 GHz each suitable for LTE/WiFi applications. The performances of the proposed design are verified through both simulation and measurement. The measured results are in good agreement with simulated result. Slight frequency shift and losses are still in acceptable range.

A 2.4 GHz SlW-based circular resonator for bandpass filter application

A design of 2.4 GHz bandpass filter is developed based on Substrate Integrated Waveguide (SIW) using printed circuit board technology. The circular cavity structure using TM010 mode is employed in the design of this bandpass filter. To prove the concept, the filter structure is fabricated using Rogers RT5880 with dielectric constant, εr = 2.2 and height of substrate 1.57 mm. The design was simulated using high frequency circuit simulator and was measured using vector network analyzer. The measured results are in good agreement with simulated result. Slight frequency shift and losses are still in acceptable range.

Substrate integrated waveguide radiating bandpass filter for c-band applications

This paper presents a novel design of 4 GHz substrate integrated waveguide (SIW)radiating bandpass filter using multilayer technique on the Printed Circuit Board.The circular cavity structure using TM010 mode for both filter and rectangular antenna areemployed in the design of this radiating bandpass filter. To realize the technique, modes of SIW filter and microstrip antenna are coupled using rectangular aperture at common ground plane.The simulation result shows good antenna gain and radiation pattern that prove the capability to integrate SIW filter and microstrip antenna directly without requirement of external matching, thus reduce the overall size of the device. To prove the concept, the multilayer structure is fabricated using Rogers RO3003 with dielectric constant, εr = 3. The measured results show good agreement with the simulated results.

An investigation of electron mobility in Leucaena Leucocephala Wood Plastic Composite for THz photoconductive antenna radiation enhancement

Photoconductive antenna (PCA) is promising devices that are most frequently used in Terahertz (THz) generation and detection system. However, THz PCA has limitation due to low output power (μW) and inefficient sources. Substrate material is one of parameters considered to enhance the THz output power radiation of PCA. This paper is aimed to investigate the electron mobility in Leucaena Leucocephala (Local Malaysian name Petai Belalang) Wood Plastic Composite for THz PCA radiation enhancement using Hall-effect measurement system (ECOPIA HMS-3000) equipment by 300 Kelvin room temperature with variance input currents. Data gathered by this material is compared with material made of 100% polypropylene polymer relatively with the same data input and supported by the literature research results.