Showing papers by "Norbahiah Misran published in 2016"

Design of a Miniaturized Meandered Line Antenna for UHF RFID Tags.

Abstract: A semi-circle looped vertically omnidirectional radiation (VOR) patterned tag antenna for UHF (919–923 MHz for Malaysia) frequency is designed to overcome the impedance mismatch issue in this paper. Two impedance matching feeding strips are used in the antenna structure to tune the input impedance of the antenna. Two dipole shaped meandered lines are used to achieve a VOR pattern. The proposed antenna is designed for 23-j224 Ω chip impedance. The antenna is suitable for ‘place and tag’ application. A small size of 77.68×35.5 mm2 is achieved for a read range performance of 8.3 meters using Malaysia regulated maximum power transfer of 2.0 W effective radiated power (ERP).

A New High Performance Hibiscus Petal Pattern Monopole Antenna for UWB Applications

Abstract: A new ultra wideband (UWB) antenna is proposed that can be efficiently used for different wireless UWB applications. The antenna structure has a very simple patch with Hibiscus petal pattern. The antenna is designed on a 31×31 mm2 Rogers RT/duroid 5870 substrate with permittivity 2.33, loss tangent 0.0012, 1.57 mm thickness and a 50 ohm impedance microstrip fed line. Different parts of antenna are analyzed to optimize the antenna properties. The novel patch of the antenna is modified to achieve the desired wide bandwidth behavior. The simulation results show that the antenna has an impedance bandwidth of 145% from 3.2 to 20 GHz with VSWR<2, a stable omnidirectional radiation pattern, an average gain of 5.1 dBi and the average radiation efficiency is 85%, which is ideal for use in UWB applications. The proposed antenna was successfully prototyped and the measured results are consistent with simulation.

Sol–gel synthesis of transition-metal doped ferrite compounds with potential flexible, dielectric and electromagnetic properties

Abstract: A compact and flexible dielectric substrate with efficient electromagnetic performances both in flat and bending conditions are presented in this paper. The proposed substrates, for potential microwave radiator applications have been fabricated from Mn doped zinc ferrite compounds by sol–gel method. Prepared MnxZn(1−x)Fe2O4, (x = 0.0, 0.2, 0.4, 0.6, 0.8) substrates were analysed structurally by X-ray diffraction spectroscopy and morphologically studied by scanning electron microscopy. We studied the optical and dielectric properties in the microwave range to evaluate the new material as a dielectric substrate for microwave applications. The prepared flexible substrates exhibit high dielectric permittivity and low dielectric loss in the microwave frequency range. For the proof of concept, the electromagnetic performances both at flat and bending conditions were verified by loading an electromagnetic radiator. We report the detailed measured performances of the reflection coefficient below −10 dB, average efficiency above 73% and average realized gain above 1.5 dBi within the operational bandwidth for the first time. The measured stable omnidirectional radiation patterns both in flat and bending conditions also confirm the potential of the proposed material to be used as a new flexible dielectric substrate.

A compact disc-shaped super wideband patch antenna with a structure of parasitic element

Abstract: In this paper, a disc-shaped monopole antenna has been investigated for super-wideband applications with a structure of parasitic element. The proposed SWB antenna consists of disc-shaped patch and a partial ground plane with a structure of parasitic element. The parasitic element consists of 4 rectangular embedded slots on the ground plane. This parasitic element on the ground plane leads the UWB frequency band into the SWB frequency band. This proposed SWB antenna is fed by a microstrip line and is printed on low dielectric FR4 material of 1.6 mm thickness. All the simulations are performed using commercially available, finite element method (FEM) based Ansoft high-frequency structure simulator (HFSS) software and CST Microwave Studio. Measured results exhibit that the proposed disc-shaped antenna shows a wide bandwidth which covers from 2.90 GHz to more than 20 GHz, with a compact dimension of 25 mm x 33 mm for VSWR = 2062. 22) are a good deal sounder than the existing super wideband antennas which make it appropriate for many wireless communication systems such as L, C, X, UWB, Ku, and SWB bands.

Ray tracing technique for shaping a dual reector antenna system

Abstract: In radio astronomy applications, antennas having the highest aperture efficiencies are requested. In order to meet this request, a reector shaping program for dual reector antennas has been developed. The design procedure is based on the geometrical optics where differential equations have been formulated to dene the ray trace of the antenna system. Recently, the fourth generation programming language MATLAB has become well known for its numerical computing environment and very useful three-dimensiona data visualization functions. The authors wished to make a dual reector shaping program by a ray tracing method in MATLAB. In this paper, details of the program are explained, and antenna ray tracing results are shown visually by three-dimensiona viewgraphs. The numerical results are compared with the theoretical ones to conrm the correctness of the developed shaping program for a Cassegrain dual reector antenna system. For uniform aperture distribution therst side lobe level is numerically obtained as {17.59 dB, which can be further reduced through shaping to {24.67 dB and {30.65 dB for parabolic and squared parabolic, respectively.

Dual band printed patch antenna on ceramic---polytetrafluoroethylene composite material substrate for GPS and WLAN applications

Abstract: In this paper, a design concept of modified rectangular shape slotted patch antenna with microstrip feed is proposed for GPS and WLAN applications. The proposed simple planar design of the planar antenna is composed of partially extended radiating surface which is loaded with L-shape slot and two wide square slots. The optimized design of the antenna has overall dimension of $$40 \times 40\; \mathrm{mm}^{2}$$40?40mm2 and is fabricated on 1.905 mm thick high dielectric substrate $$(\varepsilon _{r} = 10.2)$$(?r=10.2) of high frequency copper laminated ceramic composite substrate. The antenna design, simulation and parametric analysis have been performed on finite element method based full-wave 3D electromagnetic field simulation software. The experimental results show that the fabricated antenna has achieved impedance bandwidths (S11 $$\le -10$$≤-10 dB) of around 780 MHz (1.13---1.91?GHz) at resonant frequency of 1.48?GHz and 1220?MHz (4.83---6.05?GHz) at resonant frequency of 5.61?GHz respectively. The gain of the fabricated antenna gives maximum value of 3.42 and 4.37?dBi for lower and upper frequency band of operations respectively. The proposed antenna shows almost consistent radiation patterns with adequate radiation efficiency over the frequency bands which make the antenna appropriate for providing services in both L1/L2 GPS and 5.2/5.8?GHz WLAN bands.

Partial ground dielectric resonator antenna for LTE Femtocell base stations

Abstract: This study aims to design a new cuboid dielectric resonator antenna (DRA) for LTE Femtocell base stations. The dielectric waveguide model (DWM) was used to carry out the dimension of cuboid dielectric resonator antenna. The dielectric cuboid is based on a high dielectric constant ceramic material, which is e=30. The feeding structure is dependent on microstrip feed line resides above a FR4 substrate. However, a partial ground plane is used to increase Bandwidth and to act like an omnidirectional antenna. This proposed antenna is suitable for several applications such as LTE and WiFi. The achieved impedance bandwidth is above 800 MHz. This work was implemented based on CST Microwave Studio and fabrication.

Bandwidth performance analysis of different glass's dielectric permittivity on reflectarray radiating element

Abstract: This paper presents the performance of bandwidth from a triangular loop shape radiating element stacked on a glass with variation of dielectric permittivity values. In this study, the dielectric permittivity value of the glass was varied from 1.5 to 10. A Kapton film (radiating element) was positioned on top of the glass and grounded with a copper layer. The radiating element was designed to operate at Ku-band frequency range. Simulation results from the CST microwave studio showed that a small dielectric permittivity value improve the reflectarray element bandwidth significantly.

Analysis on element shape geometries to enhance reflection coefficient and gain of reflectarray antenna

Abstract: An analysis on element shape geometry is presented in this paper to enhance the reflectarray element bandwidth, to produce a more reliable phase distribution over the reflectarray antenna aperture and to have a good reflection element performance. The shape analysis consists of circular patch element, circular ring element and circular square ring element. The reflection coefficient parameter focuses on phase range, phase slope, bandwidth and return loss performance for each analysis and presented in this paper. It is shown that the proper selection of element shape geometry will significantly affects the reflection coefficient of reflectarray element and the antenna gain performances.

Analysis of EM absorption reduction using paper based negative indexed metamaterial shielding

Abstract: In this paper, a paper based negative indexed metamaterial is proposed for electromagnetic absorption reduction of portable wireless devices. The metamaterial structure has been designed and characterized using FIT technique based EM simulator CST Microwave studio. The main outcomes of the paper are EM absorption reduction by 14.23% and 15.3% at 0.9 GHz and 1.80 GHz, respectively using metamaterial shielding.

Capacitive loading radiating element for reconfigurable reflectarray at Ku-band

Abstract: A single-layer linearly polarized reflectarray element namely Concentric Circle Square Ring (CCSR) for Ku-band is presented in this paper. The adjustment of the reflected phase of the reflectarray element via variable capacitive loading which is realised by connecting the two rings with varactor diode. By using the full-wave EM field simulator-CST, simulation of the single element to perform exact measurement in standard waveguide were obtained. The measurement indicates that the element with attachment of varactor diode has good capability of changing the reflection phase between 0 to 20 V suppliede to the diode.

Dual band resonance of millimeter-wave frequencies antennas on LTCC

Abstract: This paper presents an aperture-coupled microstrip antenna, which is operating at dual band of millimeter-wave (mmW) frequencies, 28GHz and 38GHz. The aperture antenna was integrated with multilayer substrate construct on 5-layers Low temperature Co-fiber Ceramic (LTCC) with 5 mils thickness. The driven patch was applied to enhance the bandwidth. The bandwidths using are 9.1 percent at 28GHz and 9.4 percent at 38GHz with the direction gains are 6.8dBi and 5.6dBi at 28GHz and 38GHz respectively. Total dimension of single element antenna is 7mm × 4.1mm × 0.68mm.

Design of planar slot-loaded antenna for energy harvesting

Abstract: In this paper, a multi slot-loaded microstrip dual band antenna is presented for energy harvesting applications at 2.4/5.8GHz Wireless Local Area Network (WLAN) bands. The incorporation of C-shape slot, rectangle slot and a pair of I-shape slots on patch antenna was supportive for excitation of dual distinctive resonance bonds. Such integration was also found effective in delivering good impedance matching for the proposed dual band antenna, with 24.24dB return loss recorded at lower resonance 2.445GHz and 39.9dB return loss at higher resonance 5.805GHz. The total efficiency of proposed antenna exceeded 80 percent with a realized gain of more than 6.4dBi at both resonances.

Detection of breast cancer using electromagnetic techniques: A review

Abstract: Breast cancer is the most well-known malignancy of non-skin and the second leading reason of cancer death among the women in the world after the lung cancer. In this review, the development of the microwave imaging system is described for breast cancer detection depending on the ultra-wideband imaging system, which is a promising emerging technology that uses the dielectric contrast between malignant, benignant and normal fibro glandular breast tissues at the microwave frequen- cies. Some breast cancer detection techniques such as Magnetic Resonance Imaging (MRI), Mammography, Ultra-Wide Band (UWB), Ultrasound and their performances have also been reviewed. There are some restrictions of the existing UWB imaging systems such as they have no ability to detect the breast tumor at the beginning period, having no 3D pictorial representation of tumor size in all systems and a multiple array antenna in respect of complex system. This encourages the improvement of the extended signal processing techniques for ultra-wideband imaging systems and initiates a more appealing imaging scenario. The limitations and running challenges of the microwave imaging system have been discussed completely with some feasible suggestions. Confidently, this thorough survey has been done here to overcome this limitations of the existing and proposed systems.

Superposition of reflectarray elements for beam scanning with phase range enhancement and loss improvement

Abstract: The utilization of varactor diode is advantageous as it offers the beam scanning capability as required for reflectarray antenna but it often said as the contributor to high losses. A superposition of reflectarray elements controlled by varactor diode is evaluated with dynamic phase range enhanced and loss improved at Ku-band for a successful design of an antenna element in the array environments. Simulated results of reflectarray element under normal incidence of two designs with capacitive variation integrated represents the use of varactor is executed by CST Microwave Studio. In capacitance range of 0.08p to 1.0pF, a dynamic phase range of 3230 demonstrates at 13.964 GHz and 14.828 GHz with reflection loss 1.66 dB and 0.99 dB respectively as a result of superposition.

Compact wrench-shaped resonator loaded UWB antenna with notched frequency characteristics

Abstract: In the manuscript, the design of a wrench-shaped resonator loaded ultra-wideband (UWB) antenna has been proposed using notched frequency characteristics. The antenna is composed of the patch with microstrip feed line, a wrench-shaped resonator, and a slotted partial ground plane. A notched frequency is created due to the electromagnetic coupling of wrench-shaped resonator. In order to observe the effects of wrench-shaped resonator, a parametric study has been executed. Measured results are compared with simulations (with and without notched bands) and a stable similarity has been observed. The surface current, radiation patterns and the impedance (imaginary and real) have ensured the compression of wanted notched frequency bands

New NRI Metamaterial for Multi-band Operation

Abstract: A new negative refractive index (NRI) metamaterial unit cell is presented in this study. The negative refractive index property is being displayed by the unit cell of metamaterial in the four distinct microwave frequency bands. Finite integration technique was adopted to evaluate the property of the material. More than 1 GHz bandwidth region was found exhibiting NRI property for the material in the microwave spectra.