Mohamad Kamal A. Rahim

A Compact Frequency-Reconfigurable Narrowband Microstrip Slot Antenna

A frequency-reconfigurable microstrip slot antenna is proposed. The antenna is capable of frequency switching at six different frequency bands between 2.2 and 4.75 GHz. Five RF p-i-n diode switches are positioned in the slot to achieve frequency reconfigurability. The feed line and the slot are bended to reduce 33% of the original size of the antenna. The biasing circuit is integrated into the ground plane to minimize the parasitic effects toward the performance of the antenna. Simulated and measured results are used to demonstrate the performance of the antenna. The simulated and measured return losses, together with the radiation patterns, are presented and compared.

Frequency-Reconfigurable Microstrip Patch-Slot Antenna

A frequency-reconfigurable microstrip patch switchable to slot antenna is proposed. The antenna is capable of frequency switching at nine different frequency bands between 1.98 and 3.59 GHz. The patch is resonating at 3.59 GHz, while the slot produces eight different operating frequencies between 1.98 and 3.41 GHz. Five RF p-i-n diode switches are positioned in the slot to achieve frequency reconfigurability. Simulated and measured results are used to demonstrate the performance of the antenna. The simulated and measured return losses, together with the radiation patterns, are presented.

Bandwidth Enhancement and Radiation Characteristics Improvement of Rectangular Dielectric Resonator Antenna

Abstract-A simple, compact, wideband rectangular dielectric resonator antenna (RDRA) is presented. The bandwidth is enhanced using a proper tapered strip excitation from one side of the DR. The radiation characteristics are improved by adding a shorted narrow strip to the opposite side of the excitation. In addition, by using this shorted strip, further improvement of the bandwidth is obtained. A parametric study on the strip dimension is carried out. The proposed DRA with good radiation characteristics offers a measured bandwidth of 96% between 2.13 and 6.08 GHz for VSWR <; 2.

Left Handed Metamaterial Design for Microstrip Antenna Application

This paper describes the design and simulation of the left-handed metamaterial structure incorporated with a single microstrip patch antenna. The combination of the modified square rectangular split ring (SRR) and the capacitance loaded strip (CLS) was used to obtain the negative value of permeability, mur and the negative permittivity, epsivr. From the simulation done, the gain of the antenna has been increased up to 4 dB. This had proven that the LH MTM can enhance the gain of the antenna.

The design of nine element quasi microstrip log periodic antenna

This paper described the design, simulation and fabrication of the inset feed log periodic antenna with nine elements. The antennas have been modeled using microstrip lines and S parameter data from an individual single element. The data is extracted from the simulation and combined with the microstrip transmission line. The properties of antennas such as bandwidth, gain, cross-polar isolation and half power beamwidth have been investigated and compared between simulation and measurements. A bandwidth up to 51% is achieved by using nine-element arrays. The cross-polar isolation of the log periodic antenna is in the range of 10 to 30 dB. The typical half power beamwidth (HPBW) of the log periodic antenna is 40/spl deg/ for E plane and 60/spl deg/ for H plane. The gain of the antenna relative to the dipole antenna ranges from -3 dB to 5 dB.

Textile UWB Antenna Bending and Wet Performances

The vision and ideas of wearable computing systems describe future electronic systems as an integral part of our everyday clothing that provides the wearer with such intelligent personal assistants. Recently, there has been growing interest in the antenna community to merge between wearable systems technology, ultrawideband (UWB) technology and textile technology. This work aimed to make closer steps towards real wearability by investigating the possibilities of designing wearable UWB antenna where textile materials are used for the substrate as well as the conducting parts of the designed antenna. Two types of conducting materials have been used for conducting parts, while a nonconducting fabric has been used as antenna substrate material. A set of comparative results of the proposed design were presented and discussed. Moreover, effects on the return loss by means of measurements for each fabricated antenna prototype under bent and fully wet conditions were discussed in more details.

Comparison between Straight and U shape of Ultra Wide Band Microstrip Antenna using Log Periodic Technique

This paper described the design, simulation and fabrication of the ultra wideband (UWB) antennas for straight and U shape using seventeen elements log-periodic (LP) technique. The antennas have been modeled using microstrip lines and S parameter data from individual single element. The data is extracted from the momentum simulation and combined with the microstrip transmission line. The properties of antennas such as bandwidth return loss and radiation pattern have been investigated and compared between simulation and measurements. A bandwidth for UWB antenna is achieved using seventeen element arrays. The cross-polar isolation of the UWB antenna is in the range 8 to 20 (IB for straight shape. The typical half power bandwidth (HPBW) of the UWB antenna is 40deg. Furthermore, the return loss of the antenna is above -10 dB from both simulation and measurement..

FREQUENCY AND PATTERN RECONFIGURABLE YAGI ANTENNA

A novel frequency and pattern reconfigurable Yagi antenna is proposed. The antenna is formed by a driver, a reflector and two directors. The introduction of switches using a PIN diode at the arms of the driver element produces three switchable frequencies at 1.25 GHz, 1.85 GHz and 2.45 GHz. By controlling the switches at the directors and reflector, the radiation pattern can be configured to near omni-directional pattern or directional pattern at those three frequencies. Simulated and measured results are used to demonstrate the performance of the antenna. The simulated and measured return losses and the radiation patterns, are presented and compared. It was found that the gain of the antenna increases from 3.3 dB to 5 dB in a directional pattern, when compared to the near omni-directional pattern.

Microstrip dipole antenna analysis with different width and length at 2.4 GHz

This paper discusses the design and simulation of microstrip dipole antenna at 2.4 GHz. In this antenna design, Agilents Advanced Design System (ADS) software using momentum simulation is employed to analyze the entire structure. Different width (W = 3, 5, 7, 9 mm) of the arm of dipole antenna is analyzed to study on the performance of frequency resonance. From the simulation, the wider the width will lower the resonance frequency of the antenna. Different width makes the frequency resonance of the antenna shifting lower or higher than 2.4 GHz. In this case, the length (L) of the dipole arm needs changes. Optimization value of the length is needed to make the frequency resonance at 2.4 GHz. The simulation result gives the bandwidth achieved of this microstrip dipole antenna is between 11 and 13 %. Three different width of dipole antenna have been fabricated and presented here in this paper. The properties of antenna such as input return loss and bandwidth have been investigated and compared between simulations

Planar Wideband Circularly Polarized Antenna Design With Rectangular Ring Dielectric Resonator and Parasitic Printed Loops

A wideband circularly polarized (CP) rectangular dielectric resonator (DR) parasitically coupled to a printed rectangular loops is presented. The DR is housed in a thin dielectric substrate with a microstrip line and narrow strip printed from one side and a ground plane and conducting loops and lines connected to the ground plane. The DR is linearly polarized, and for CP, we introduced printed conducting loops in the other side of the DR, which produce the orthogonal polarization with the required quadratic phase. Several loops are used to achieve the wide CP band. The final design achieves CP with 51% bandwidth. The reflection coefficient, axial ratio (AR), radiation patterns, gain, and efficiency of the antenna are studied, and reasonable agreement between the measured and simulated results is observed.