Mohamadariff Othman

A Novel 5.8 GHz High Gain Array Dielectric Resonator Antenna

In this paper, a novel nine elements array dielectric resonator antenna (DRA) is presented. The DRA was excited by a microstrip feeder with a rectangular aperture coupled slots. The slot positions were determined based on the characteristic of standing wave ratio over a short ended microstrip. The measured gain of the array DRA operating at 5.84 GHz was about 10 dBi having impedance bandwidth of 60MHz. The proposed DRA exhibits an enhancement of the gain in comparison with a single pellet DRA. The size of the whole antenna structure is about 60 mm× 40mm and potentially can be used in wireless systems.

Simulation and Experimental Investigators on Rectangular, Circular and Cylindrical Dielectric Resonator Antenna

In this paper, theoretical and simulation studies on rectangular and annular dielectric resonator antenna (DRA) made of TiO2 was reported. The ceramic was fabricated by solid state reaction at 1200◦C. The structural and dielectric properties were investigated by X-Ray Diffraction (XRD), Field Emission Electron Microscopy (FESEM) and network Analyzer. The XRD results showed the presence of rutile phase and the microstructure comprised of fine grain (0.2–0.5 μm) and large grain 1.0–1.5 μm. The rectangular and annular shape TiO2 DRA with high dielectric constant (e = 84) and low loss tangent (0.080) were fed with 50Ω microstrip transmission line and comparision between the various shape were investigated. The return loss, input impedance and radiation pattern TiO2 DRA was studied. Design simulation results using CST Microwave Studio 2008 also was presented.

NOVEL MODELING AND DESIGN OF CIRCULARLY POLARIZED DIELECTRIC RESONATOR ANTENNA ARRAY

This paper presents a design of circularly polarized dielectric resonator antenna (DRA) array. The dielectric resonators (DRs) were excited by rectangular aperture coupling slots feed with a linear microstrip. The slot positions were determined based on the characteristic of standing wave ratio over a short ended microstrip to deliver the maximum amount of coupling power to the DRs, in order to improve the array gain Each DR element was rotated 45 - with respect to the sides of the exciting slot to generate circular polarization pattern. The DRA array was modeled and simulated as a parallel RLC input impedance component using Agilent (ADS) software, since that will ensure the resonant frequency of the antenna as primary design step before simulating in (CST) software and doing the measurements. The results of the return loss, gain radiation and pattern axial ratio are shown. The gain of the proposed array in X band was about 8.5dBi, while the 3dB axial ratio bandwidth started from 8.14 to 8.24GHz. The impedance bandwidths started from 8.14GHz to 8.26GHz. The proposed DRA exhibited an enhancement of the gain in comparison to a single pellet DRA. The size of the whole antenna structure is about 40mm £ 50mm and can potentially be used in wireless systems.

Wideband dielectric resonator antenna for C-Band application

Two segment rectangular dielectric resonator antenna of high permittivity (epsivr = 30) ceramic material was design and fabricated at C-band. The antenna was fed with 50Omega microstrip transmission line. In this design, both dielectric resonators (DRs) are separated with metal plate which acting as shorting post. The length of the two DRs is 7.7 mm and 2.2 mm respectively. The optimum distance from the port was chosen at 17.195 mm. The simulated result shows this type of antenna produces wide bandwidth and omni-directional radiation pattern. The simulated gain was 5.5 dB. The result shows the potentiality of this antenna to be used in the wireless communication.

A Ka-band horn antenna excited with parasitic dielectric resonator antenna

A pyramidal horn antenna excited with parasitic dielectric resonator (DR) antenna for use at Ka-band frequencies is proposed. This antenna been divided into two parts, microstrip-fed rectangular slot DR antenna and a pyramidal horn. DR antenna consists of five identical cylindrical parasitic DR fed by a microstrip feedline through a coupling rectangular slot in the ground plane between them. It is designed to parasitic type for high gain, high isolation and wideband characteristics. Simulated result shows the antenna produce high gain that is larger than 19.8dB. CST simulation results of the electrical performance for pyramidal horn antenna operating at 38GHz are presented.

Design of hairpin band pass filters for K-Band application

This paper presents Chebyshev three and four poles microstrip hairpin filter for radar applications. The filters are operated at K-band frequency segment of 20-20.3 GHz. The filters were designed using Genesys software and implemented on Roger 5870 substrate. The results from simulation and measurement show that both filters were operating at the desired specification. Based on the experimental analysis, it was observed that the filter with four elements better than the three which was quite agree to other researchers.

Recent advances in microwave reflector antenna technology

This paper presents some recent developments in microwave reflector antenna technology. The main focus of this research is on novel reflector antenna designs to overcome the challenges caused by the rising communication systems. Prototype implementation will be described in this paper; published microwave reflector antenna frequency range, low profile and compact designs, wideband reflector antennas, low sidelobe level, low cross polarization and enhanced gain microwave reflector antennas review is brought up.

Small and compact rectangular dielectric resonator antenna for WLAN applications

In this paper, small dielectric resonator antenna was design and developed by using high permittivity dielectric material of 55. The dimensions of the dielectric resonator were 5.4 mm (width), 9.3 mm (length), and 3.14 mm (height). This DRA operate at a frequency around 5 GHz. It was excited with microstrip line where the position of the DR on the microstrip was varied to get good coupling. CST Microwave Studio was used for the simulation of the return loss and radiation pattern. A comparison between the measured and simulated value of the return loss and radiation pattern were also discussed.

3.5 GHz rectangular dielectric resonator antenna

In this paper, dielectric resonator antenna operated at 3.5 GHz was design and simulated using CST Microwave Studio and subsequently fabricated. Direct microstrip line of 50 Omega was used as the feeder. In this design, rectangular shape was used as the dielectric resonator as it offers more option to control the resonant frequency. The position of rectangular DR was varied to determine the best coupling and the distance was found to be 6 mm. The simulated results of the return loss, resonant frequency together with radiation pattern were compared with the measured results. It was found that rectangular DRA has potential to be used in wireless system.

A novel multi-band dual-segment rectangular Dielectric Resonator Antenna

Modern wireless communication devices demands for multiband operation using single antenna to reduce complexity of the system. In this work a multi-band rectangular shaped Dielectric Resonator Antenna (DRA) is designed and analyzed. A two segments rectangular dielectric resonator with different permittivitys are stacked together, and a notch is created in the top segment of the resonator. By optimizing notch value and position of rectangular Dielectric Resonator (DR) over the microstrip feed line multi-band operation of the antenna is achieved. Parametric study of the antenna is done so as to achieve optimum performance of the antenna in both operating bands. The lower operating frequency band of the antenna gives approximately 14 % (5.3 GHz to 6.1 GHz) impedance bandwidth, whereas upper operating frequency band of the antenna yields almost 8 % (7.2 GHz to 7.8 GHz) impedance bandwidth. Simulation of the proposed antenna is performed using Computer Simulation Technology (CST 2014). Return loss of the antenna is measured using Agilent Technology PNA N5245A network analyzer. A close agreement between simulation and measured results is obtained.