S. Subahir

Gain enhancement of air substrates at 5.8GHz for microstrip antenna array

This paper concerned on enhancement of gain for microstrip patch planar array antenna. The structure in this project is 2 by 2 microstrip patch planar array antenna using air substrate with εr= 1at frequency 5.8 GHz. Frequency for 5.8GHz can be applied to unlicensed WiMAX. In this project, the simulation is performed by using the simulation software Computer Simulation Technology (CST) Microwave Studiowhich is a commercially available electromagnetic simulator based on finite difference time domain technique. The novelty of the design is the application of air to replace regular Flame Retardant 4 (FR-4) materials as the substrate.The substrate used for the design is C-foam (thickness = 3mm) which represent as air gap. Copper foil with thickness 0.12mm is used as the patch. The performance of the designed antenna was analyzed in term of bandwidth, gain, return loss, VSWR, and radiation pattern.

Design of reconfigurable dual-band E-shaped microstrip patch antenna

A novel compact size of reconfigurable E-shaped microstrip single patch antenna was designed and analyzed for dual-band at 3.02 GHz and 6.38 GHz frequencies. The basic antenna was designed to operate at 3.02 GHz and with reconfigurability in frequency, it will operate at 6.38 GHz. The physical parameters of the novel structure as well as its partial ground plane will be analyzed and optimized using commercial computer simulation technology (CST) packages. Return loss (S11), voltage standing wave ratio (VSWR) and gain will be carried out. The return loss of the optimized reconfigurable E-shaped microstrip patch antenna has to be less than -10dB at 3.02 GHz and 6.38 GHz frequencies band. The reconfigurable antenna was then to be measured by vector network analyzer (VNA) to carry out its S11 and VSWR result. The result from simulation and measurement will be compared. The proposed antenna is very promising for various modern communication applications such as wireless and satellite application.

Backlobe reduction using mushroom-like EBG structure

This paper investigated the capability of Electromagnetic band gap (EBG) in reducing the backlobe of the microstrip patch antenna array. Four different size of EBG have been simulated and the radiation patterns are presented. The results show that if only one slot of antenna is inserted into the structure, (3mm×6mm) EBG produced the best back lobe reduction that is from -10.24db to -17.67dB. If the number of slot of EBG increased up to 9 columns, only (3mm×3mm) EBG has shown an improvement while for the other size, the back lobe is getting worse.

Aperture coupled microstrip antenna array integrated with DGS and parasitic elements

This paper presents a novel design of aperture coupled microstrip antenna (ACMSA) integrated with DGS and parasitic elements. The basic design of the proposed antenna is 2 by 2 planar array with aperture coupler feeding technique. Four dumbbell-shaped DGS are etched on the ground plane, for back radiation reduction, which is sandwiched between the upper and lower substrates. Both of the substrates are Rogers Duroid 5880 of thickness 0.767mm with dielectric constant of 2.2. Twelve trapezoidal-shaped parasitic elements are placed onto the first substrate, three besides each patch, for gain enhancement. The antenna design is simulated in CST Microwave Studio 2011 software based on operating frequency of 5.8GHz. The results show that back lobe level is reduced from 4.6dB to 0.1331dB. With the parasitic element, the gain of the antenna which was dropped, from 11.8dB to 11.2dB when DGS is added, is improved to 11.5dB. Reflection coefficient for the antenna is -27.50dB. This design concept can be useful in reducing the back radiation of aperture coupled microstrip antenna.

Performance of an aperture coupled microstrip antenna on LTCC technology at 5.8 GHz

Studies on the performance of an aperture coupled microstrip line-fed patch antennas on low temperature co-fired ceramic (LTCC) operating at unlicensed 5.8 GHz frequency band is presented. Observation on the controlling parameters of the aperture coupled antenna on LTCC is conducted to investigate the effect of aperture slot at various layers with different height. The proposed concept of this idea is simulated on Ferro A6M microstrip ceramic substrate and compared with the simulated of aperture coupled antenna on Flame Retardent 4 (FR-4) substrate. The aperture coupled antenna using LTCC and FR4 layout is presented in this paper by using the CST 2011 simulation results.

Skills Retention in Basic Offshore Safety and Emergency Training (B.O.S.E.T)

This chapter investigates the basic offshore safety and emergency training (B.O.S.E.T) skills retention phenomena among offshore professionals. To identify B.O.S.E.T skills retention, the researchers developed a role-play scenario test which is based on brace positions and heat escape lessening posture (H.E.L.P). The test was conducted over a period of 6 months with 38 offshore professionals. Analysis of the test data suggests that B.O.S.E.T skills retention depreciate with time at a rate of 24 % within the first 6 months. Skills level was estimated to be at 70 % within 9 months from the initial B.O.S.E.T training. Further forecast analysis suggests that the B.O.S.E.T skills level will be at 50 % by the end of 3 years. The research postulates that the current B.O.S.E.T refresher system maybe sufficed to ensure that B.O.S.E.T skills is sustained at an acceptable level within the 3 years period.

Occurrence of space VLF due to the earthquake events

In recent years many research has pinpointed possible precursory signs that occur before an earthquake. One of the precursory signs that associated with earthquake (EQ) is the electromagnetic phenomena. Among these, the VLF electromagnetic emission is recognized as one of the most promising candidates for short-term earthquake prediction. This project focuses on revealing the perturbation of the VLF signals during earthquake event. In order to reveal possible earthquake precursor though the changes of VLF signal, Northern Sumatera Indonesia earthquake that happened on 7th April 2010 is chosen as a study case. The observation was made on the day of the earthquake event occur. VLF data deployed from system called Atmospheric Weather Electromagnetic System for Observation Modeling and Education (AWESOME) through its VLF receiver. Matlab is used to simulate the data. The result shows that strong correlation between VLF and determination of earthquake precursors.

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.

10 GHz multilayer antenna proximity coupled feed using Low Temperature Co-fired Ceramic technology

In this paper, a 10 GHz multilayer antenna with proximity coupled feed using Low Temperature Co-fired Ceramic (LTCC) technology is presented. The multilayer antenna was designed to operate at 10.01GHz with return loss of -11.523283 dB. The antenna was simulated using CST Microwave Studio. The performance of the antenna in terms of antenna radiation pattern and antenna gain were analyzed and discussed. The results show that the gain is 3.435dB.

A multilayer fractal patch antenna using LTCC technology

In this paper, a 10 GHz fractal patch antenna using Low Temperature Co-Fired Ceramic (LTCC) Technology has been used. A comparison between two different designs of radiating patch which are conventional patch and fractal patch has been done to get the better result. A Minkowski first iteration fractal micro strip patch antenna has been used in this design. This antenna design consists of eight layer of substrate. The ground plane at the back of layer 1, the feeding line at layer 6 and the radiating patch at the layer 7. The dielectric constant for LTCC technology is 5.9 and the substrate thickness is 0.096 mm. Ferro A6S has been used for the substrate and silver has been used for the patch. The overall thickness in this design is 0.8mm. A multilayer fractal patch antenna was design and optimized using the CST Microwave Studio Suite 2012. For the conventional radiating patch, the simulated S11 results show a minimum of -13.99 dB at 10GHz and the maximum gain of 2.98 dB. The simulated S11 results for fractal radiating patch show a minimum of -14.28 dB at 10.14GHz. The simulated radiation pattern shows a maximum gain of 10.02 dB. The bandwidth of the antenna has been increased from 2.33 MHz to 16.1 MHz. From the result, it can be seen that the radiating patch with fractal design gives better result compared to the conventional patch.