Abdelhamid M.H. Nasr

Abdelhamid M.H. Nasr

University of Michigan

H-index: 6

North America-United States

Abdelhamid M.H. Nasr Information

University

University of Michigan

Position

___

Citations(all)

100

Citations(since 2020)

84

Cited By

48

hIndex(all)

6

hIndex(since 2020)

5

i10Index(all)

2

i10Index(since 2020)

2

Email

University Profile Page

University of Michigan

Abdelhamid M.H. Nasr Skills & Research Interests

metamaterials

material characterization

baluns

power dividers

antennas

Top articles of Abdelhamid M.H. Nasr

A CPW Resonator for Complex Dielectric Characterization of Thin Films at W-Band

A coplanar waveguide (CPW) composite resonator for dielectric characterization of thin films at -band is presented in this article. The sample holder is fabricated using gold evaporation on a fused silica wafer to minimize the resonator losses. The composite resonator is composed of two inductively coupled short-circuited CPW resonators to improve the quality factor of the sample holder. The technique is suitable for complex dielectric characterization of very thin materials (a few hundreds of micrometers), such as vehicular paint due to the high sensitivity of the CPW resonator to the superstrate material. An inversion algorithm is developed to calculate the real part of the sample’s permittivity from the shift in the resonant frequency and the imaginary part from the change in the quality factor of the composite resonator after being loaded by a thin film of the unknown material. The CPW sample holder is fed by 1-mm …

Authors

Abdelhamid MH Nasr,Kamal Sarabandi

Journal

IEEE Transactions on Instrumentation and Measurement

Published Date

2024/1/9

Active Windshield Antenna for 5G Applications

Active millimeter-wave (MMW) vehicular antenna with simultaneous multi-beam, for 5G V2X application, is presented. The antenna achieves both high gain and wide angular coverage through multi-array design. Each array has a fixed beam direction and a separate feeding network. The beams have sufficient beamwidths such that the total pattern ensures simultaneous elevation plane coverage. The design consists of four dual-polarized patch arrays. Each array radiates in a different range of elevation angles with beams maxima at 40°, 20°, 0° and −20° with respect to the normal of the windshield. The antenna is matched across the entire 28 GHz 5G band that ranges from 24 GHz to 30 GHz. Miniaturized Wilkinson power dividers are incorporated for feeding each array which ensures minimum beam scanning with frequency. A single active beamformer chip is integrated in the design to feed the two polarizations …

Authors

Abdelhamid Nasr,Fred Schaible,Abdel Halim Mohamed,Kamal Sarabandi

Published Date

2023/7/23

Wideband Circularly Polarized Modular Active Phased Array for Vehicular Satellite Communication

This paper presents a wideband circular polarized patch element in X- and Ku-bands for vehicular satellite communication. A 2x2 array of the element is designed and fabricated with overlapped 10-dB impedance and 3-dB axial ratio band of 10.7–13 GHz. The 2x2 array enables modular design of larger arrays. Each 2x2 array is controlled by an 8-channel beamformer integrated circuit mounted on an interposer. The interposer circuit simplifies routing of dc and digital lines on the surface of larger arrays.

Authors

Behzad Yektakhah,Abdelhamid Nasr,Abdel Halim Mohamed,Kamal Sarabandi

Published Date

2023/7/23

A low-cost millimeter-wave 5G V2X multi-beam dual-polarized windshield antenna

Design procedure and experimental validation for a millimeter-wave (MMW) vehicular antenna with simultaneous multi-beam, for 5G V2X application, is presented. The design overcomes the constraint for requiring both wide angular coverage and high gain through a compact multi-array design. Each array is designed to have a fixed beam direction and sufficient beamwidth so that the overall pattern guarantees simultaneous coverage in the elevation plane. The multi-array idea is a cost-effective technique compared to employing phase shifters and beam steering of a single array and avoids latency associated with beam steering. The proposed design is composed of three compact dual polarized patch arrays. Each array covers different elevation angles, and their beam maxima are chosen to be at 10°, −20° and −40° with respect to the normal of the windshield. The antenna covers the entire 28 GHz 5G band …

Authors

Abdelhamid MH Nasr,Kamal Sarabandi

Journal

IEEE Open Journal of Antennas and Propagation

Published Date

2022/11/25

W-band dielectric characterization of automotive paint

A rectangular waveguide sample-holder is proposed for characterization of dielectric constant of thin sheets, where the sample is mounted in the longitudinal direction. This is a desired configuration as it provides higher sensitivity in measurement of complex dielectric constant and ease of sample preparation for WR-10 waveguides. Unlike conventional rectangular waveguide techniques, this technique relies on the resonance behavior of the reflection coefficient from the sample to accurately estimate the dielectric constant of the sample under test. A rectangular waveguide sample holder was fabricated, and different samples were characterized. The estimated dielectric constant values were verified using a CPW resonator technique.

Authors

Abdelhamid Nasr,Kamal Sarabandi

Published Date

2022/7/10

Ultrawideband characterization of complex dielectric constant of planar materials for 5G applications

A broadband (1–35 GHz) time-/frequency-domain reflection technique for measuring the complex dielectric constant of low-loss dielectric slabs is presented. The technique uses a coplanar waveguide (CPW) transmission line sample holder for measurements. In addition to the standard substrate materials, the technique is suitable for the characterization of materials, such as glass, as it does not require complicated sample machining and preparation. The procedure is based on comparing the measured effective dielectric constant and the attenuation constants for both the loaded and unloaded CPW line sample holder. The effective dielectric constant and the attenuation constant are first modeled as a function of the real and imaginary parts of the superstrate’s dielectric constant using a 2-D numerical line calculator. Samples under test are assumed to be nonmagnetic and have their material resonances at …

Authors

Abdelhamid MH Nasr,Adib Y Nashashibi,Kamal Sarabandi

Journal

IEEE Transactions on Instrumentation and Measurement

Published Date

2021/8/5

CPW resonators for dielectric characterization of sheets at 77 GHz

A resonant-based dielectric measurement technique at W-band is presented in this paper. The sample holder makes use of two cascaded coplanar waveguide (CPW) resonators to improve the overall quality factor. The CPW resonator is fabricated over a single crystal quartz substrate to minimize the dielectric loss. The resonator acts as a very sensitive sensor to the material placed on top of it, in the form of a superstrate. The technique is capable of accurate characterization of the real and imaginary parts of the dielectric constants of planar dielectric sheets. The proposed technique is validated through fabrication and measurements.

Authors

Abdelhamid Nasr,Kamal Sarabandi

Published Date

2021/12/4

Miniaturized couplers using multi-mode star-junction

This paper proposes a novel multi-mode star junction, which consists of eight three-conductor structures connected in a star configuration. It also proposes its equivalent circuit model and its application in the design of compact size 90° hybrid and rat-race couplers. The areas of the proposed designs are 50% and 20% of the conventional ones, respectively, without degrading the electrical characteristics. The couplers are fabricated and characterized. Measurements, which are in a very good agreement with the EM simulations, confirm the theoretical predictions.

Authors

Mohamed HA Elsawaf,Abdelhamid MH Nasr,Amr ME Safwat

Published Date

2020/8/4

Multi-beam dual-polarized windshield antenna with wide elevation coverage for 5G V2X applications

A wideband multi-beam 5G antenna system for vehicle-to-everything (V2X) communication is presented. The antenna is composed of three separate arrays with radiation patterns that covers the forward upper half elevation plane. The designed arrays maxima are located at angles 10°, -20° and -40° with respect to the windshield normal. Each array is composed of three-element dual-polarized patches. The gain of the beams varies from 11 to 9.6 dBi at 28 GHz and it covers the 28 GHz millimeter frequency range from 26.5 GHz to 29.5 GHz. A feeding network for each array is carefully designed for minimal beam deviation, as low as ± 5°, across the operating frequency range. Moreover, for interior placement of the antenna the challenging issues pertaining to the windshield is discussed.

Authors

Abdelhamid Nasr,Kamal Sarabandi,Mourad Takla

Published Date

2020/7/5

See List of Professors in Abdelhamid M.H. Nasr University(University of Michigan)

Abdelhamid M.H. Nasr FAQs

What is Abdelhamid M.H. Nasr's h-index at University of Michigan?

The h-index of Abdelhamid M.H. Nasr has been 5 since 2020 and 6 in total.

What are Abdelhamid M.H. Nasr's top articles?

The articles with the titles of

A CPW Resonator for Complex Dielectric Characterization of Thin Films at W-Band

Active Windshield Antenna for 5G Applications

Wideband Circularly Polarized Modular Active Phased Array for Vehicular Satellite Communication

A low-cost millimeter-wave 5G V2X multi-beam dual-polarized windshield antenna

W-band dielectric characterization of automotive paint

Ultrawideband characterization of complex dielectric constant of planar materials for 5G applications

CPW resonators for dielectric characterization of sheets at 77 GHz

Miniaturized couplers using multi-mode star-junction

...

are the top articles of Abdelhamid M.H. Nasr at University of Michigan.

What are Abdelhamid M.H. Nasr's research interests?

The research interests of Abdelhamid M.H. Nasr are: metamaterials, material characterization, baluns, power dividers, antennas

What is Abdelhamid M.H. Nasr's total number of citations?

Abdelhamid M.H. Nasr has 100 citations in total.

What are the co-authors of Abdelhamid M.H. Nasr?

The co-authors of Abdelhamid M.H. Nasr are Kamal Sarabandi, Amr M. E. Safwat, Adib Nashashibi, Behzad Yektakhah.

    Co-Authors

    H-index: 78
    Kamal Sarabandi

    Kamal Sarabandi

    University of Michigan-Dearborn

    H-index: 23
    Amr M. E. Safwat

    Amr M. E. Safwat

    Ain Shams University

    H-index: 18
    Adib Nashashibi

    Adib Nashashibi

    University of Michigan-Dearborn

    H-index: 9
    Behzad Yektakhah

    Behzad Yektakhah

    University of Michigan

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