Amir Zaghloul - Academia.edu (original) (raw)

Papers by Amir Zaghloul

2023 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (USNC-URSI)

International Applied Computational Electromagnetics Society Symposium - Italy, Mar 22, 2015

This paper presents the effects of solder on spiral antenna performance by simulating different s... more This paper presents the effects of solder on spiral antenna performance by simulating different solder gaps connecting spiral antenna to balun, and comparing return loss and boresight gain of spiral antenna.

2019 URSI Asia-Pacific Radio Science Conference (AP-RASC)

Electromagnetic spectrum is a scarce resource that is becoming increasingly contested and congest... more Electromagnetic spectrum is a scarce resource that is becoming increasingly contested and congested with the allocation of available spectrum to newer communications technologies. Several radio-frequency operators especially radars are now required to share their spectrum with communications. In this work, we investigate the spectrum sharing between a radar and a communications system from a game-theoretic perspective. Since both systems compete for the same resource, their interaction can be modeled as a two-person zero-sum game. Specifically, we analyze transmit power allocation in a symmetric game where a player is unaware of the strategies adopted by the competitor. Our power allocation optimization constraints include preset signal-to-interference-plus-clutter-plus-noise ratio and maximum interference tolerance.

arXiv (Cornell University), Mar 23, 2021

We propose a low-cost reconfigurable metasurface transmitter to implement generalized polarizatio... more We propose a low-cost reconfigurable metasurface transmitter to implement generalized polarization-space modulation (GPSM) that has been proposed for next-generation wireless communications. Unlike conventional multiple-input multiple-output GPSM, our electromagneticallycompliant, reduced form-factor design using Barium-Strontium-Titanate film yields more than two polarization states. Full-wave simulations show our optimized design achieves 0.08-0.95 polarization conversion ratio with 5% bandwidth at 28 GHz and bit error rates comparable or better than conventional systems.

COMSAT TECHNICAL. REVIEW is published twice a year by the Communications Satellite Corporation (C... more COMSAT TECHNICAL. REVIEW is published twice a year by the Communications Satellite Corporation (COMSAT). Subscriptions, which include the two issues published within a calendar year, are: one year, S20 U.S.; two years, 35;threeyears,35; three years, 35;threeyears,50; single copies, 12;articlereprints,12; article reprints, 12;articlereprints,3. Overseas airmail delivery is available at an additional

[1991] GaAs IC Symposium Technical Digest

The design and packaging approaches for a lightweight, beam-forming matrix (BFM) for a Ku-band mu... more The design and packaging approaches for a lightweight, beam-forming matrix (BFM) for a Ku-band multibeam phased-array antenna are presented. The BFM is assembled in a modular package using Wilkinson dividers/combiners; GaAs monolithic microwave integrated circuit (MMIC), 5-bit phase shifters; and highly integrated driver/level-shifter electronics on alumina substrate boards. Tests over the 11- to 13-GHz frequency range demonstrate uniform performance for

2009 IEEE Antennas and Propagation Society International Symposium, 2009

A 9 X 13 printed microwave lens beam former was investigated numerically using MoM, and good perf... more A 9 X 13 printed microwave lens beam former was investigated numerically using MoM, and good performance was predicted across the quadruple band 6 GHz - 25 GHz. TTD behavior across entire band was achieved by array factor comparisons, with good beam quality demonstrations. Future work on this lens will involve the power efficiency study and prototype measurement validations.

2018 2nd URSI Atlantic Radio Science Meeting (AT-RASC), 2018

AATRASC2018AZQNfinal. The new material will be anisotropic or bi-anisotropic. The analysis and si... more AATRASC2018AZQNfinal. The new material will be anisotropic or bi-anisotropic. The analysis and simulation show the multiplicative effect of the hybrid structure, operating at high frequencies using specially designed host materials. In this paper, we take the first step in proving the concept of permeability upgrading by performing experimental verification of a hybrid structure that uses commercially available host material at low frequency. Measuring the SSS-parameters of thin layers of the host material, followed by using documented parameter retrieval algorithms, we calculate the host material's permeability, permittivity, and loss tangent versus frequency. The measurements are repeated for the metamaterial-inserted hybrid structure to obtain the same parameters and observe the permeability upgrading, or multiplication.

2020 XXXIIIrd General Assembly and Scientific Symposium of the International Union of Radio Science, 2020

A reflective metasurface cell allows electromagnetic waves to be reflected with a desired phase. ... more A reflective metasurface cell allows electromagnetic waves to be reflected with a desired phase. The reflection phase can also be tuned by incorporating active circuit elements into the metasurface cells/pixels. In this paper, we present a design concept of circular inter-digitated (CID) selfphased reflective (SPR) metasurface pixel/cell that offers a reconfigurable reflection phase. Unlike using active circuit elements in conventional approach, we use a constituent material in dielectric layer supporting the metasurface. As the constituent material permittivity changes, the resonance wavelength of the metasurface also changes, which results in a phase change. The presented pixel/cell design consists of a dual-circular ring, incorporating a meandered slot line, or an interdigitated line, in between. All are integrated on a dielectric layer with metal backing that is used as a constituent material. The design can achieve polarizationindependent phase control with 220 degrees of tunable phase and loss of less than 2 dB. The design can be applied in coding metasurfaces to control the scattering pattern, where reflection phase tuning is needed. The design can also be used in reflectarrays.

The Applied Computational Electromagnetics Society Journal, 2021

─ In this letter, a multifunction aperture array is proposed for ultrawideband (UWB) scanning and... more ─ In this letter, a multifunction aperture array is proposed for ultrawideband (UWB) scanning and polarization reconfiguration. The UWB array consisted of linearly polarized elements is capable of operating in four polarization modes (+45° linear polarization (LP),-45° linear polarization, left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP)). This work involves two essential techniques: (a) A new beam-scanning UWB array synthesis approach. An iterative convex optimization strategy is utilized to determine the element locations and obtain the minimum sidelobe level (SLL) for multiple patterns. (b) The polarization reconfigurable technique for beam-scannable arrays. In this part, a sequential rotation and excitation compensation (SR-EC) technique provides polarization reconfiguration for a beam-scannable array consisting of linearly polarized elements. A beam-scanning UWB array is designed by using the proposed UWB array synthesis approach and the SR-EC polarization reconfigurable technique. The Feko numerical result shows 0°-60° beam peak steering, a 4:1 bandwidth (1-4 GHz), and fourpolarization reconfigurability.

Computer methods and programs in biomedicine, 2018

The aim of this research is to study the behaviour of a human head during the event of an impact ... more The aim of this research is to study the behaviour of a human head during the event of an impact of a cricket ball. While many recent incidents were reported in relation to head injuries caused by the impact of cricket balls, there is no clear information available in the published literature about the possible threat levels and the protection level of the current protective equipment. This research investigates the effects of an impact of a cricket ball on a human head and the level of protection offered by the existing standard cricket helmet. An experimental program was carried out to measure the localised pressure caused by the impact of standard cricket balls. The balls were directed at a speed of 110 km/h on a 3D printed head model, with and without a standard cricket helmet. Numerical simulations were carried out using advanced finite element package LS-DYNA to validate the experimental results. The experimental and numerical results showed approximately a 60% reduction in th...

2016 URSI International Symposium on Electromagnetic Theory (EMTS), 2016

Insertion phase in multi-layered metamaterials play an important role in understanding the consti... more Insertion phase in multi-layered metamaterials play an important role in understanding the constitutive parameters of the material. Simulations and measurements show the distinct large phase change across the frequency band in which the metamaterial exhibits special parameters. This paper addresses the phase behavior for materials that use loops or rings for magnetic properties and rods, wires, or probes for electric properties. Continuous wires and cut wires in the structure show different properties, especially in the frequency regions where negative refraction occurs. The conjecture that negative refraction is a manifestation of insertion phase variations is reiterated in this paper.

2015 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2015

Spiral antennas work over broadband, but conventional EBG structures work over narrow frequency b... more Spiral antennas work over broadband, but conventional EBG structures work over narrow frequency band. Bandwidth of EBG structures can be increased by cascading EBG vertically in multiple layers or progressively in a single layer. This paper presents a uniform height via-less broadband progressive EBG structure designed for spiral antennas. The design is fabricated and simulated boresight gain and return loss performances are compared against measurements. The effects of feed point soldering to the spiral are also discussed.

IEEE Transactions on Antennas and Propagation, 1972

The gain of arrays of X/2-dipoles in front of am ground plane is calculated by the mutual resista... more The gain of arrays of X/2-dipoles in front of am ground plane is calculated by the mutual resistance method as a function of dipole ground-plane spacing and number of elements, illustrating Manuscript

2008 Asia-Pacific Microwave Conference, 2008

In this paper, we present a two-dimensional azimuth beam steerable antenna design by applying mic... more In this paper, we present a two-dimensional azimuth beam steerable antenna design by applying microwave lens beam former. The antenna array aperture is realized with uniformly spaced microstrip patches. The beam former utilizes each beam port to produce corresponding phase shift across the array aperture so as to generate the azimuth scan. The demonstrated antenna operates at the M frequency

2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)

This paper presents the results of a trade-off analysis in developing design concepts for the Med... more This paper presents the results of a trade-off analysis in developing design concepts for the Medium Data Rate (MDR) Satellite on the Move (SOTM) and Satellite on the Pause (SOTP) terminals using flat plate antenna technology. Numerous antenna configurations including single and multipanel approaches were considered as part of the study. The preferred number of panels is identified by studying the effect of multi-panel approach on the G/T and Gain performance of the antenna. The effects of different tracking mechanisms on the antenna performance are analyzed. The analysis leads to a preferred antenna design, and confirms that a flat plate antenna configuration is both feasible and desirable for SOTM/SOTP applications from performance, size, mass and cost considerations.

The 23rd Digital Avionics Systems Conference (IEEE Cat. No.04CH37576)

This paper extends the previous results to complete the analysis of air-to-air message-overlap st... more This paper extends the previous results to complete the analysis of air-to-air message-overlap statistics using a graphical method. The extension takes into account critical factors such as radio frequency propagation and receiver characteristics to provide better estimates of the ...

CCNC 2006. 2006 3rd IEEE Consumer Communications and Networking Conference, 2006.

... Amir I. Zaghloul Virginia Polytechnic Institute and State University Falls Church, VA22043 za... more ... Amir I. Zaghloul Virginia Polytechnic Institute and State University Falls Church, VA22043 zaghloul@vt.edu ... devices having bandwidths that are much narrower than the UWB waveform, eg, wireless phones, GPS receivers, aeronautical communications, and wireless LAN, etc. ...

IEEE Conference on Ultra Wideband Systems and Technologies, 2003

Page 1. PULSE SHAPING FILTER DESIGN IN UWB SYSTEM Dongsong Zeng*, AnnamalaiAnnamalai Jr.**, and A... more Page 1. PULSE SHAPING FILTER DESIGN IN UWB SYSTEM Dongsong Zeng*, AnnamalaiAnnamalai Jr.**, and Amir I. Zaghloul** 'Glocom, Inc., Germantown, MD 20874, dzeng@glocom-us.com **Virginia Polytechnic Institute and Sate University ABSTRACT ...

2008 IEEE Antennas and Propagation Society International Symposium, 2008

A flared rectangular horn is corrugated along the E-plane flaring walls. The corrugations are in ... more A flared rectangular horn is corrugated along the E-plane flaring walls. The corrugations are in the form of rectangular grooves parallel to the horn axis. The depths of the grooves are optimized to produce the tapered aperture that is needed for certain radiation pattern requirements. Two designs are presented in this paper. The first design is for a narrow beam and low sidelobes in the E-plane pattern. The second design is for equal patterns in the E- and H-planes. The choice of the flaring function determines the E-plane radiation pattern. A linear flaring is chosen for the narrow beam and an exponential flaring is chosen for the equal E- and H-plane patters.