El Sayed Ahmad

On miniaturization of efficient ultrawideband printed quazi-Yagi antenna array for indoor applications

This paper describes the design and analysis of a compact and efficient ultrawideband unidirectional printed antenna array for indoor applications.A12.2×6.3×1 cm antenna array is capable of covering an ultra-wide frequency band starting from LTE up to Wi-MAX with an average gain approaching 5 dBi over the entire bandwidth. In comparison with the already existing antenna systems in the wireless market for similar purposes, the proposed antenna has considerably better performance and supplementary compactness, which makes it competitive among other antenna models. Simulation results have also shown low cross polarization levels, where the sidelobe level was also minimized by introducing a special reflecting element in the designed model. Adopting the proposed antenna in indoor communication systems would surely enhance the quality of signal within the covered area as well as minimize the number of access points needed for a given network.

Ultra-wideband quasi-Yagi circular dipole antenna for wireless applications

This paper describes a novel ultra-wideband quasi-Yagi circular dipole antenna. The antenna consists of two parallel circular dipole radiators of different resonant lengths. The bandwidth which can meet both impedance and radiation characteristic requirements is greater than 100%. The important advantages of this antenna are ultra-wideband, directive property, and low cross polarization levels with high front to back lobe ratio. A prototype is fabricated and measured.

Multi-resonant compact patch antenna with fractal slots on the basis of smith chart configuration

This paper describes the design and analysis of a multi-resonant compact patch antenna with fractal slots on the basis of Smith Chart geometry for indoor communication systems. A 60mm × 60mm × 1mm single patch antenna with periodic fractals in the form of combined r and x circles is capable of resonating at some desired sub-bands starting from LTE to WI-MAX with good enough directional characteristics greater than 3 dB in average within the whole frequency band. The dielectric material used for the proposed Microstrip patch antenna is Rogers TMM4 with dielectric constant of 4.5 and the patch is made up of perfect electric conductor (PEC). The proposed fractal geometry possesses multiband behavior at 0.7 GHz, 1.15 GHz, 1.8 GHz, 2.4 GHz, 3.7 GHz, 5.2 GHz and 5.8 GHz. In comparison with the already existing antenna systems in the wireless market for similar purposes, the proposed antenna has considerably shown better performance and supplementary compactness which makes it competitive among other antenna models.

Compact and efficient ultra-wideband printed quazi-yagi array antenna for indoor applications

This paper describes the design and analysis of a compact and efficient ultra-wideband unidirectional printed Array antenna for indoor applications. A 12cmx12cmx1cm array antenna is capable of covering an ultra-wide frequency band starting from LTE up to WI-MAX with an average gain exceeding 5dBi over the entire bandwidth. In comparison with the already existing antenna systems in the wireless market for similar purposes, the proposed antenna has considerably shown better performance and supplementary compactness which makes it competitive among other antenna models. Simulation results have also shown low cross polarization levels, where the sidelobe level was also minimized by introducing special reflecting element in the designed model. Adopting the proposed antenna in indoor communication systems would surely enhance the quality of signal within the covered area as well as minimize the number of access points needed for a given network.

Double-plane beamwidth control of conventional rectangular waveguide antennas using curved slotted surfaces

Conventional slotted waveguide antennas are well known and prominently used for many military and even marketable applications. This is due to their different advantageous electrical and mechanical characteristics. It is also well known that this type of antennas is a typical array of slots with which the width of the main beam can be controlled in only one plane by using a different number of elements in such antennas. Numerous research, discuss the capability of using an array of such antennas in order to narrow down the main beam in both planes and even achieve a scanning phased array. In this paper, a new and broader approach is presented concerning beam width control of the typical configuration of such antennas. This work presents the ability to control the main lobe in both planes using only one slotted waveguide to a certain extent. Different simulation results are considered at the 2.4GHz frequency demonstrating improved effectiveness in terms of directivity and high gain as well as minimizing the side-lobe level and mechanically controlling the main lobe of the antenna.

Design of a low profile end-fire antenna

An array of monopoles antenna over a ground plane that radiates a directive lobe in the end-fire direction is described in this paper. The design uses the rigorous method described in [1] in order to synthesis the radiation though the strong cumulative coupling between the monopoles. A gain higher than 20 dB was achieved in the end-fire direction over a 4.5% bandwidth.

Wide Angular Aperture Circularly Polarized Low-Profile EBG Antenna

This paper describes the design of a compact and wide angular circularly polarized low-profile EBG antenna. Except at 3.7 GHz and for θ lower than −25° in the plane Φ equals to 0°, the modelized structure provides an axial ratio lower than 3 dB, over a wide angular aperture of 60° and over a bandwidth of 5.3% ([3.7 GHz–3.9 GHz]). It has a very low height of 11.9 mm (𝜆/7 at 3.8 GHz). A prototype has been manufactured, and the measured performances, considering the tolerance of the measurement base (±0.5 dB), are quite similar to the simulated ones.

High gain printed dipole array with reflectors and directors

Since many years, a lot of studies has been lead to developed reconfigurable antennas. Phase scanning, beam steering or frequency tuning are, notably, the main interests of the antennists. Therefore planar array antennas has been developed, in order to control all of those parameters (examples in [1],[2],[3],[6]). In our letter, the simplicity of the design of a directive antenna with only printed dipoles is shown. We extend a technique used in [4], which aims to get a high gain, a high sidelobe level rejection and a low level of back radiations. In the first part of this paper, we present the basic printed structure (compouned of one radiating element, one reflector and one director). In the second part, we present a 8×1 array of the basic structure, with a balanced power distribution in order to increase the gain and decrease the side lobe level. We optimize those antennas with the software CST Microwave Studio.