M. K. A. Rahim

An array of dielectric resonator antenna for wireless application

This project describes a design on array dielectric resonator antenna using disk shape. The dielectric resonator antenna (DRA) consists of high dielectric constant materials, high quality factors and mounted on a grounded dielectric substrate of lower permittivity. DRA is fabricated from low-loss and high relative dielectric constant material of various shapes whose resonant frequencies are functions of the size, shape and permittivity of the material. Two dielectric resonators is introducing as an array. The selected dielectric disks are operating at frequency of 2.4 GHz with dielectric constant of 34.73. The microstrip transmission line has been used as a feeding line for the resonator. The microstrip line is quarter wavelength where the frequency that applied from the input can get same with the output and divider was introduced in this layout. The simulation process was done using Computer Simulation Technology (CST) Microwave Studio. The antenna has been fabricated on the FR-4 microstrip board using the wet etching technique. The DRA is operating at the frequency bands used for IEEE 802.11b/g Wireless LANs.

Microstrip Sierpinski carpet antenna design

Low cost of fabrication and low profile features of microstrip antennas, attract many researchers to investigate the performance of this antenna in various ways. Today, fractal antenna becomes popular among the researcher because they have a peculiar properties that make them suitable for multiband applications. Fractal technologies allowed us to design miniature antennas and integrate multiple telecommunication services such as cellular (GSM 900 and GSM 1800), wireless LAN, GPS and HiperLAN into a single device. Microstrip Sierpinski carpet antenna is proposed for a multiband operation. The fractal antenna offer solutions for the integration of all this application.

The Investigation of PIN diode switch on reconfigurable antenna

The investigation and simulation of PIN diode as a switch on reconfigurable antenna are described in this paper. The simulation of the PIN diode model is constructed on CST Simulation tools with the integration of single patch antenna. The radial stub biasing circuit is used for fabrication with the antenna. Three different locations of PIN diode with radial stubs biasing circuit are investigated and analyzed. The result shows the separation of biasing circuit and antenna give a better performance in term of return loss and current distribution.

Effects of human body and antenna orientation on dipole textile antenna performance and SAR

Wearable textile antennas are supposed to be integrated within the clothing or secured on the body. Therefore, the placement of the antennas and their orientation need to be carefully determined. In this paper, the interaction between a single band dipole textile antenna for wireless off-body communication applications with human body is examined. The simulations are performed by means of CST Microwave Studio with a single band 2.4 GHz patch dipole antenna as the radiating source. The effects of human body are taken into account and different antenna orientations, locations and distances from the body are also considered in this study. Results have clearly indicated that the human body has notably shifts the antenna resonant frequency and modifies the radiation pattern at the frequency investigated. Furthermore, the results obtained show that the SAR values are significantly influenced by the antenna orientation and position. SAR is increased by utmost 16 % when the textile antenna is horizontally orientated compared to antenna in vertical orientation.

Wideband Sierpinski carpet monopole antenna

This paper described the design and fabrication of the fractal Sierpenksi carpet monopole antenna. The properties of antennas such as bandwidth and radiation pattern have been investigated. Wide bandwidth with input return loss of -10 dB has been achieved from 1 GHz to 10 GHz using this fractal antenna. The radiation patterns have been investigated at 2.73 GHz and 4.29 GHz. The cross polar isolation is in the range of -20 dB for both frequencies. The radiation pattern is in the direction of the main lobe.

Circular Polarization Fractal Koch microstrip patch Antenna using single-fed EM coupled ring Resonators

This paper describes the design and analysis of a Circular Polarization Fractal Koch Antenna using single-fed electromagnetic (EM) coupled ring resonator at 2.4 GHz. By applying fractal Koch, the proposed antenna size is reduced about 5% compared to the square patch using single-fed EM coupled ring resonator antenna. The simulation process has been done by CST software. Simulation as well as measurement results with antenna design have been presented and it shows that a good agreement in term of return loss and axial ratio. The antenna exhibits a bandwidth of 1.65% at −10dB return loss and 3dB Axial Ratio (AR) bandwidth of 0.78% with gain of 5.97dBi

Analysis of dual layer unit cell with minkowski radiating shape for reflectarray antenna on different substrate properties

This paper describe the analysis and design for a double layer unit cell X-Band reflectarray. In this design, a novel minkowski shape structure has been developed as an auxiliary unit cell element for the dual layer X- bands reflectarray to achieve wider reflection phase. A progressive phase range wider than 360 degree has been achieved by modifies the square patch into a minkowski shape and printed on a dual layer substrate. Two different types of substrate are used for the construction of this design, which are the Taconic RF-35 and FR-4. Simulation results of a unit cell with minkowski shape of printed radiating element on different substrate have been briefly discussed and compared.

Electromagnetic Band Gap Structure for Planar Ultra Wide Band Antenna

An innovative technique involving the usage of a mushroom Electromagnetic Band Gap (mEBG) structure with an ultra wideband (UWB) antenna is reported in this work. A single unit of mEBG lattice is incorporated within a novel UWB antenna to perform the band rejection operation. The antenna can be fixed to reject or reduce the transmit power for any band within the UWB spectrums of frequencies through a careful design of this mEBG structure, thus solving the problems concerning interference and reducing the requirements for complex filtering electronics within the UWB devices.

Dual band polarization insensitive metamaterial absorber in X-band

This paper presents the design of dual band polarization insensitive metamaterial absorber at 9 GHz and 10 GHz. The unit cell of the metamaterial consists of four circular rings copper with copper lines printed on 0.8 mm thick FR4 substrate with dielectric constant of 4.6 and loss tangent of 0.019. The simulated result shows that the dual band metamaterial absorber achieves 97.00% and 97.77% for normal incident electromagnetic waves at 9 GHz and 10 GHz respectively. The corresponding full width half maximum (FWHM) are 3.59% and 3.31%. The simulation result verified that the absorber well performance at any polarization of incident electromagnetic waves.

Chipless RFID tag based on meandered line resonator

A meandered microstrip transmission line resonator is proposed for the design of chip-less RFID tag. The 6 bit resonator is operates from 3 to 5 GHz. The tag consists of a micro strip open stub resonators and two Ultra-wide Band (UWB) monopole antennas. The 30 mm × 35 mm chip-less RFID tag is designed on Taconic substrate with permittivity of 2.75. The modification technique from the straight line of micro strip open stub toward meandered line is introduced.