Ahmed Kishk

Ahmed Kishk
Concordia University Montreal · Department of Electrical and Computer Engineering

PhD Electrical Engineering

About

901
Publications
138,451
Reads
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17,657
Citations
Introduction
Design millimeter wave antennas and microwave circuit components for 5G and beyond based on the efficient guiding structure of gap waveguides in different technologies. Vast varieties of applications in 5G, MIMO, and Massive MIMO, satellite communication, and Microwave imaging for Biomedical Applications.
Additional affiliations
May 2011 - present
Concordia University Montreal
Position
  • Professor and Canada Research Chair Tier 1
June 2009 - July 2010
Chalmers University of Technology
Position
  • Professor
August 1986 - May 2011
University of Mississippi
Position
  • Professor (Full)
Education
September 1982 - February 1986
University of Manitoba
Field of study
  • Electrical Engineering
September 1981 - February 1983
University of Manitoba
Field of study
  • Electrical Engineering
September 1978 - July 1980
Ain Shams University
Field of study
  • Applied Mathematics

Publications

Publications (901)
Article
An infinitesimal dipole model (IDM) for an antenna including mutual coupling is used to model the radiation patterns of aperiodic arrays. Each radiating element is modelled by a set of infinitesimal dipoles. The mutual coupling between the elements is calculated and the far field radiation pattern of the antenna is computed in a fast and efficient...
Article
Full-text available
Low-profile directional ultra-wideband (UWB) antennas are strongly demanded in many UWB applications. However, few such UWB antennas have been reported. To meet the demands, an original novel low-profile directional UWB antenna-the self-grounded Bow-Tie is developed and presented here. This new UWB antenna has a compact and simple geometry, and ult...
Article
Some focusing properties of Fresnel zone plate (FZP) lens antennas in the near-field region are presented at the ka-band. Simulated and measured results of the FZP antenna show displacement of the maximum intensity of the electric field along the axial direction from the focal point toward the antenna aperture. This displacement increases as the an...
Article
An H-shape ultrawideband (UWB) dielectric resonator (DR) mounted on a vertical ground plane edge with broadside radiation patterns is evaluated for breast tumor detection. In order to scan the whole breast, the proposed DR sensor can be attached to the skin without a need for matching medium. The sensor has a wide half power beamwidth, therefore pa...
Article
A very fast and efficient method for designing compact antenna arrays preserving the maximum channel capacity of multi input multi output (MIMO) systems using infinitesimal dipole model (IDM) theory is presented. Using this method each antenna element is replaced by a set of infinitesimal dipoles producing the same electric fields of the antenna. T...
Conference Paper
Full-text available
A dual-polarized 1×4 slot antenna array is proposed supporting a millimeter-wave application. The dual-polarized antenna is excited with two microstrip lines based on Substrate Integrated Gap Waveguide. The simulated return loss for both ports achieves a sufficient matching level over 10% bandwidth and beyond 12 dBi Gain for both polarizations. The...
Article
RF energy harvesting (RFEH) is an emerging technique in the field of wireless technology. The key components of this system are receiving antenna, matching network, and rectifier circuit. A rectifier circuit based on a tuned matching circuit is demonstrated in this paper for RFEH applications. The topology of this rectifier circuit is suitable for...
Article
A dual-band rectifier is presented for RF energy harvesting (RFEH) and microwave power transfer (MPT) applications. Starting with a single-band rectifier, the second band is added by utilizing a half-wavelength transmission line (HWTL) in the matching network (MN). A series diode topology using HSMS-2860 Schottky diode is used for power conversion....
Article
A novel wideband self-decoupled loop-coupled antenna element is proposed for the fifth-generation (5G) multiple-input multiple-output (MIMO) smartphones. The proposed loop-coupled antenna element generates two resonance modes of 0.75 and 1 λ. With the help of these two resonance modes, a wide bandwidth is achieved. The self-decoupled performance is...
Conference Paper
In this paper, the ports voltage and current of the TL are obtained using a new form of TL equation and its derivative. A system of linear equations is obtained according to the coupled versions of the telegrapher equations and the boundary conditions at terminals. The solution to that system of equations provides both far-end and near-end crosstal...
Article
Orbital angular momentum (OAM) carrying vortex beams has been studied and realized using different methods. However, the designed devices are usually capable of generating fixed OAM modes. Here, the concept of a modular radiating system based on tightly cascaded transmitarrays (TAs) provi-ding a compact and user-accessible modular radiating system...
Article
Full-text available
Dual-band base station antenna (BSA) arrays with shared aperture have attracted considerable attention for the fifth-generation (5G) communication. The focus is mainly on decoupling between lower-band (LB) and higher-band (HB) antennas (i.e., cross-band decoupling). The in-band BSA decoupling techniques are usually not applicable to broadband dual-...
Article
Full-text available
Dielectric resonator antenna (DRA) arrays with enhanced isolation and front-to-back ratio (FBR) are proposed in this paper. Specifically, each DRA element is mounted on a small and separated ground plane; all the DRA elements (with small ground planes) share a large common ground plane. Each DRA element is excited by two differential probes at its...
Article
Full-text available
A simple antenna with a 20-dBi gain is proposed. A thorough analysis of the propagation mechanism accompanied by a unique physical insight is provided. The realized structure has a low profile, low-cost, and compact features. A detailed insight into applying the Fresnel–Huygens principle is provided.
Chapter
Environmental sensors have come a long way over the last decade, surged in variety and capabilities. Such growth was impossible without developing wireless technologies, particularly antennas, thanks to advanced numerical computation software and artificial intelligence (AI). Sensors have numerous applications in industrial environments for purpose...
Article
An efficient single-layer printed feed is used with a low-cost 3D printed polarizer. The feed is made on a single substrate layer. The proposed antenna gain is 15 dBi, and the overlapped impedance-axial ratio bandwidth is 20%. The proposed structure is a low-cost structure that can be fabricated in any modest fabrication facility. The feed does not...
Article
A compact septum-based orthomode transducer (OMT) is designed to provide dual circularly polarized states for horn antennas. The OMT is back-fed by two rectangular ports separated by a stepped tapered septum from thick to thin walls towards the common port. The OMT covers 16.7% fractional bandwidth in the V-band (55 - 65 GHz), which coincides with...
Article
A high-power Y-junction circulator is proposed for radar applications in the Ku-band (12–18 GHz). The design consists of two identical circulators combined using power splitters at all ports. The overall circulator network achieves 20-dB isolation level and return loss over the Ku-band with a peak power level of 14 kW. An internally matched divider...
Article
Full-text available
This work proposed a solution of structures built from stacking several dielectric substrates with the conducting cladding aiming for electrical contact between them (PEC-PEC). At millimeter-wave frequencies, surface roughness or imperfect flat surfaces present possible gaps that cause severe unexpected leakage. Many engineers overlooked this probl...
Article
Full-text available
The recent advancement in commercial electromagnetic computational solvers, along with the computational processing resources gives a huge advantage for antenna designers to study complex structures and optimize their performance. In addition, the huge leap in processors speeds, and the advent of parallel processing techniques made it possible to r...
Article
Full-text available
Correlations and mutual couplings in antenna arrays lead to performance deterioration of multiple-input-multiple-output (MIMO) systems. The relation between mutual coupling and correlation is complex, especially in non-isotropic multipath environments. Reducing mutual coupling does not guarantee an eventual reduction of the overall correlation and...
Preprint
Full-text available
A simple antenna with a 20-dBi gain is proposed. A thorough analysis of the propagation mechanism accompanied by a unique physical insight is provided. The realized structure has a low profile, low-cost, and compact features, a detailed link to the Fresnel-Huygens principle is provided.
Article
Full-text available
A surrogate-assisted defected ground structure design is proposed to suppress simultaneously E- and H-plane couplings in a 22 microstrip antenna array at 2.45 GHz. The DGS is designed and analyzed based on the magnetic current and mode theory. Machine learning is employed to sweep the DGS parameters within defined limits and fine-tune them to obtai...
Article
This letter proposes a hybrid decoupling structure consisting of a neutralization dielectric board, metal baffle, and feeding network to enhance the isolation in a compact large-scale base station array. Both the neutralization- and partition-based schemes are utilized to reduce the mutual coupling between antennas. The neutralization dielectric bo...
Article
Full-text available
Fifth-generation millimeter-wave devices with multiple antennas require minimal mutual interference for better overall performance. This article presents a simple but novel technique to improve the isolation between closely packed slot antenna arrays. A printed ridge gap waveguide (PRGW) structure is used to realize a low loss millimeter-wave array...
Article
A compact multi-layer substrate integrated waveguide (SIW) monopulse antenna array operating at X-band is proposed. The structure consists of four stacked layers, including one layer for the radiating 4 × 4 rectangular microstrip antenna elements and two SIW layers for the comparator network. The sum and difference modes provide orthogonal radiatio...
Preprint
Full-text available
In this paper, a design of a monopole-based four-element MIMO array antenna is proposed. The design is based on a novel technique that makes a patch be a ground plane of the next patch. Thus, each patch has a dual function. This method is named the sharing technique. Thus, for the first time, two of such antennas can be merged, providing a subminia...
Article
Full-text available
A new class of multi‐layer microstrip patch antenna (MPA) array fed by substrate integrated waveguide (SIW) cavities is presented for Ku‐band applications. An efficient compact multi‐layer SIW feeding network is designed, which has lower losses than the conventional corporate feeding network based on microstrip lines or coplanar waveguides. A 4 × 4...
Article
Full-text available
A method of improving the diversity and capacity of MIMO systems in non-isotropic multipath environments by loading a scatterer array is proposed. The difference between array diversity and superresolution imaging is discussed first. The phase differences caused by the “effective space” between adjacent antenna elements are the critical factors of...
Article
Full-text available
A decoupling structure with polarization rotation property (DSPR) is proposed to reduce the mutual coupling between co-or cross-polarized antennas. The proposed DSPR generates a neutralization wave with two orthogonally polarized components that can be controlled to cancel the original mutual coupling. The DSPR is placed above the arrays with ortho...
Article
Full-text available
This paper presents a novel method of improving the correlation performance in a compact multiple-input multiple-output (MIMO) array. Unlike the previous work, the proposed method focuses on each antenna phase distribution in the array and reduces the correlation by adjusting the near-field phase distribution using phase correcting elements (PCEs)....
Article
Full-text available
In this article, a via‐based 2.5‐dimensional (2.5D) frequency selective surface (FSS) is proposed to realize a quasi‐elliptical bandpass response with high frequency selectivity. Each FSS element is composed of two parts. Part A is a double‐layer metallic circular patches, which are etched on both sides of a thick substrate and connected by a centr...
Article
Various decoupling methods were proposed and investigated for multiple-input multiple-output (MIMO) Base Station (BS) systems. These methods can effectively decouple the dual-polarized co-polar signal but fail to decouple the cross-polarized signal, similarly limiting the BS's overall decoupling performance. In this paper, different antenna arrays...
Article
Full-text available
A new single-fed circularly polarized dielectric resonator antenna (CP-DRA) without beam squint is presented. The DRA comprises an S-shaped dielectric resonator (SDR) with a metalized edge and two rectangular dielectric resonators (RDRs) blocks. Horizontal extension section is applied as an extension of the SDR, and a vertical-section is placed in...
Conference Paper
In this paper, a novel method is introduced to compute the antenna factor parameter. The proposed approach is based on the equivalence concept of electric field radiation source and the receiver antennas in which the response at the antenna terminal is calculated efficiently with a simple equivalent circuit model. The most significant parameters af...
Article
Full-text available
A compact structure with slot splitting meandered lines defected ground is proposed to reduce the mutual coupling between two microstrip antennas with a center-to-center distance of 0.38λ. The meandered line defected ground structure is symmetrically etched on the ground between the microstrip antennas. The proposed structure is optimized and expla...
Article
Full-text available
This letter proposes a dielectric superstrate to reduce the couplings between co-polarized and cross-polarized antenna elements in realistic base station (BS) arrays. The mutual couplings are reduced by adjusting the permittivity and profile of the dielectric superstrate to create "reflected" waves to neutralize the original coupling wave. The diel...
Article
Full-text available
A Y-junction circulator based on the ridge gap waveguide (RGW) as a hosting guiding structure is designed using a developed closed-form systematic procedure. To validate the structure, an air-filled-to-dielectric-filled transition is proposed using a substrate perforation technique. The proposed RGW circulator covers the whole Ku-band with a matchi...
Conference Paper
Full-text available
In this work, a wide band slot antenna with a two-section T-shaped ridge is designed at 30 GHz based on printed ridge gap waveguide technology. Later, to enhance the antenna gain, a multi-layer stepped horn is designed with PCB substrates. The horn results in an overall increase in gain up to 11.5 dBi, and the bandwidth exceeds 26.5% from 26.5-34.6...
Article
In this communication, an effective method to suppress mutual coupling between two substrate-integrated waveguide (SIW) slot antenna arrays is presented. To achieve that, a decoupling feed network is used. The feed network is composed of a two-layer directional coupler that is connected to two SIW-slot antenna arrays directly to establish an indire...
Conference Paper
Gap waveguide is one of the promising technologies in 5G & mm-wave applications due to their low cost, low losses, and high power handling capability. In this work, we have proposed a featured design of an antenna with metamaterial layers to provide a high gain and wide bandwidth simultaneously. The antenna fed by an emerging guiding structure enti...
Conference Paper
Three configurations of substrate integrated printed log-periodic dipole array (PLPDA) antenna are presented. The antenna is designed at the ka-band for 5G applications. The antennas provide a peak gain of 12-14.5dBi with a bandwidth of about 59% (21-37GHz). First configuration, LPDA antenna backed by a flat ground, is proposed to reduce the back r...
Article
Abstract In this letter, the critical frequency of the periodic metasurface in a dielectric half‐space is studied. First, according to the mode expansion theory, the wave of the periodic metallic elements can be decomposed into different eigen‐modes. Then, as the frequency increases, partial high‐order modes are excited by the periodic metallic ele...
Preprint
Full-text available
A new single-fed circularly polarized dielectric resonator antenna (CP-DRA) without beam squint is presented. The DRA comprises of an S-shaped dielectric resonator (SDR) with a metalized edge and two rectangular dielectric resonator (RDRs) blocks. A horizontal-section is applied as an extension of the SDR, and a vertical-section is placed in parall...
Article
In this paper, first, a 2 × 2 patch antenna array based on the substrate integrated-waveguide (SIW) with high efficiency, broadband, and low cross-polarization for X-band applications, is presented. Simulation results indicate that the cross-polarization levels for the whole bandwidth within the main beam half-power beamwidth (HPBW) are less than −...
Article
A perfect magnetic conductor (PMC) packaging concept is utilized at 30 GHz, which suppresses the higher order cavity modes, improves insertion losses, and helps in developing packaged microstrip lines (PMSLs) and double-ridge gap waveguide (DRGW) transmission lines. The Quasi-TEM PMSLs are used to design quadratic hybrid, crossover, and phase shift...
Article
Full-text available
Baffles loaded by split-ring resonator (SRR) are proposed to reduce the mutual coupling for ± 45° dual-polarized multiple-input-multiple-output (MIMO) antenna. Each baffle consists of two rectangular SRR printed on one side of a 1-mm FR4 substrate. The final decoupling structure contains four baffles forming a barrier wall that reduces the coupling...
Article
Full-text available
Guided modes excited by a current source in a multilayer cylindrical structure is thoroughly investigated. The guidance condition in the multilayer structure is formulated. Based on this, three antenna configurations in cylindrical stratified media that are of strong practical interest are rigorously investigated: viz. a monopole antenna, a conform...
Chapter
In this paper, we shall present the design steps and analyze the performance of a wideband bandpass filter based on RF MEMS technology. MEMS technology enables very accurate features, which enables the repeatability of the filter. The filter is configured as a parallel edge coupled five-pole microstrip wideband bandpass filter. The concept consists...