Abdolmehdi Dadgarpour

COMPACT M-SLOT FOLDED PATCH ANTENNA FOR WLAN

This paper presents a very small size microstrip antenna suitable for WLAN application. The main patch antenna consists of an M-shaped slot with shorting wall. With a shorted triangular parasitic patch and a folded patch overall antenna size is reduced. The simulated and measured results show that by selecting a proper shorting wall width, the proposed antenna can provide an impedance bandwidth of 21.17% covering the 4.93–6.09 GHz band. The antenna size is of order 0.1094λo × 0.1094λo × 0.0544λo (6 × 6 × 3 mm3). The proposed antenna has 75% surface size reduction compared to a conventional patch antenna operating at the same centre frequency. The Eand H-plane radiation pattern across the entire operating bandwidth is provided.

Millimeter-Wave High-Gain SIW End-Fire Bow-tie Antenna

This communication presents a high-gain bow-tie antenna that operates across 57-64 GHz for application in high data rate point-to-point communication systems. The proposed antenna consists of a pair of bow-tie radiators, where each radiator is etched on the opposite side of the common dielectric substrate and fed through substrate integrated waveguide (SIW) feed-line. The bow-tie radiators are arranged to cross each other symmetrically by tilting the feed-lines by 30° to enhance the antenna gain and to obtain the required radiation pattern. The antenna is loaded with a pair of double G-shaped resonators (DGRs) that are located in a region between the radiators and SIW to suppress the back-lobe level in the H-plane. Embedded in the E-plane of the antenna is an array of zero-index metamaterial (ZIM) unit-cells whose purpose is to effectively confine the electromagnetic waves in the end-fire direction to enhance its gain performance. A prototype antenna was fabricated and its performance was measured to validate the simulation results. The proposed structure exhibits a gain of 11.8-12.5 dBi over the frequency range of 57-64 GHz with reflection coefficient less than

DESIGN AND OPTIMIZATION OF COMPACT BALANCED ANTIPODAL VIVALDI ANTENNA

- 11\;\hbox{dB}

Beam Tilting Antenna Using Integrated Metamaterial Loading

. In addition, the proposed antenna exhibits good cross-polarization, which is less than

Planar Multiband Antenna for Compact Mobile Transceivers

- 17\;\hbox{dB}

One- and Two-Dimensional Beam-Switching Antenna for Millimeter-Wave MIMO Applications

in both E- and H-planes at 60 GHz.

Beam-Deflection Using Gradient Refractive-Index Media for 60-GHz End-Fire Antenna

In this paper, the conformal finite-difference time-domain (CFDTD) method using PSO optimization is applied to design a compact directive balanced antipodal Vivaldi antenna for ultrawideband (UWB) applications. This paper demonstrates miniaturized antipodal Vivaldi antenna (32 × 35 × 1.6mm3), having low-cross polarization levels and reasonable gain from 3.1 to 10.6 GHz. The antenna peak gain is 5.25 dBi in the specified band. The simulated and experimental results of return loss, far field patterns and gain are presented.

COMPACT ULTRA-WIDEBAND PHASE SHIFTER

This communication presents a technique to re-direct the radiation beam from a planar antenna in a specific direction with the inclusion of metamaterial loading. The beam-tilting approach described here uses the phenomenon based on phase change resulting from an EM wave entering a medium of different refractive index. The metamaterial H-shaped unit-cell structure is configured to provide a high refractive index which was used to implement beam tilting in a bow-tie antenna. The fabricated unit-cell was first characterized by measuring its S-parameters. Hence, a two dimensional array was constructed using the proposed unit-cell to create a region of high refractive index which was implemented in the vicinity bow-tie structure to realize beam-tilting. The simulation and experimental results show that the main beam of the antenna in the E-plane is tilted by 17 degrees with respect to the end-fire direction at 7.3, 7.5, and 7.7 GHz. Results also show unlike conventional beam-tilting antennas, no gain drop is observed when the beam is tilted; in fact there is a gain enhancement of 2.73 dB compared to the original bow-tie antenna at 7.5 GHz. The reflection-coeflicient of the antenna remains <; - 10 dB in the frequency range of operation.

Design and Optimization of Compact Balanced Antipodal Staircase Bow-Tie Antenna

A compact planar antenna for portable multistandard transceivers is presented. The proposed microstrip-fed antenna includes a symmetrical double G-shaped radiator and slotted ground plane. A return loss of better than 10 dB is achieved at the frequency bands PCS (1850-1990 MHz), WLAN+ Bluetooth (2400-2480 MHz), WiMAX (2500-2690 MHz), WiMAX (3400-3600 MHz), HIPERLAN2 (5150-5350/5470-5725 MHz), and IEEE 802.11a (5150-5350-5725-5825 MHz). Moreover, the return loss is more than 6 dB across the DCS band (1.71-1.88 GHz). The proposed antenna is printed on a single-layered FR4 substrate, and it occupies a small volume of 40 × 30 × 1.6 mm3. The simulated and measured performance of the antenna confirms its multiband operation and omnidirectional radiation pattern.

PSO/FDTD Optimization Technique for Designing UWB In-Phase Power Divider for Linear Array Antenna Application

One- (1-D) and two-dimensional (2-D) beamforming is presented for a planar dipole antenna operating at millimeterwave bands. 1-D beamforming was achieved by using mu (μ) -near-zero (MNZ) metamaterial slabs that were integrated in the dipole antenna, where each slab was loaded with an array of low refractive-index unit-cells. The resulting radiated beam can be scanned by 35° due to the phase shift in the beam introduced by its interaction with the metamaterial slabs. In addition, the proposed antenna configuration provides gain improvement of 8 dB as the slabs effectively increase the aperture size of the antenna. An array of MNZ inclusions in the E-plane of a double dipole antenna is shown to provide scanning from -35° to +35° with respect to the end-fire direction over 57-64 GHz. 2-D beam-scanning was realized by increasing the number of MNZ unit-cells in the elevation plane of double dipole antenna. Loading the slabs in front of the double dipole antenna with 10 × 7 array of MNZ unit-cells is shown to provide a beam deflection of 35° in both the azimuth and elevation planes.