S.I. Shams

The German University in Cairo, Al Qāhirah, Al Qāhirah, Egypt

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Publications (13)0 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: A novel ultra wideband antenna is introduced in this paper in which the design, analysis and implementation are carried out. The antenna is a lotus shaped ultra wideband printed monopole antenna. The antenna dimensions are 50 mm × 43 mm. It is fed by a 50 Ω microstrip line. It operates over the frequency range of 1.42-10 GHz. It was fabricated on FR-4 substrate of thickness 1.6 mm, dielectric constant of 4.3 and loss tangent of 0.02. The group delay is investigated and measured. There is a good agreement between the simulated and the measured results for the return loss. The antenna pattern is omni-directional along the whole band.
    Antennas and Propagation Conference (LAPC), 2012 Loughborough; 01/2012
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    ABSTRACT: An arrow shaped antenna design is presented in this paper for 2.4 GHz ISM band applications. Thess applications include ZigBee [1], [2], Bluetooth [3], WLAN and WiBree. Recently, these applications have been essential for daily use in industrial and home automation in small areas because of their low power profile and long battery life. The proposed antenna is implemented to cover the 2.4 GHz ISM band in which its impedance bandwidth is about 1300 MHz (1.4-2.7 GHz). The antenna is fabricated on FR4 dielectric substrate with dimensions 25×50 mm2. The antenna has an omnidirectional radiation pattern. The measured results are in good agreement with the simulated ones.
    Antennas and Propagation Society International Symposium (APSURSI), 2012 IEEE; 01/2012
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    ABSTRACT: A miniaturized planar ultra wideband (UWB) monopole antenna is presented in this paper. By etching a C-shaped slot in the radiating patch, a band-rejected filtering properties in the WLAN band is achieved. By changing the thickness of the C-shaped slot, the notched frequency changes. An equation is introduced to calculate the thickness of the slot corresponding to a required notched frequency. The proposed antenna is compact in size with an overall dimensions of 20 mm × 18 mm and it is fed by a 50Ω microstrip transmission line. The antenna is fabricated on FR4 dielectric substrate with ε<sub>r</sub>=4.4 and height h=1.5 mm. There is a good agreement between the measured return loss and the simulated one. The antenna operates in the frequency band 2.8-12.2 GHz with omnidirectional radiation pattern.
    Microwave Conference Proceedings (APMC), 2010 Asia-Pacific; 01/2011
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    ABSTRACT: A new design of a dual-band circularly polarized antenna is introduced. The introduced antenna consists of a rectangular patch surrounded by a circular ground with additional two circles, one located above the radiating patch and the other on lower right side, result in both right hand and left hand circular polarized radiation. The antenna operates in two bands 3.3 GHz and 4.8 GHz. The first band is used in WiMax applications. The second band is used in some WLAN applications, it also works in WiMax applications. The antenna is compact in size with overall dimensions 40 mm × 40 mm . The antenna has a low profile and printed on a single side of the substrate. The feeding structure is a 50 Ω CPW. The antenna is RHCP and LHCP at 3.3 GHz and 4.8 GHz, respectively. The antenna is fabricated on FR4 substrate and the results of the return loss are measured and are in a good agreement with the simulated results.
    Microwave Conference Proceedings (APMC), 2010 Asia-Pacific; 01/2011
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    ABSTRACT: A compact multiband planar antenna is proposed for several applications: DCS-1900/PCS/UMTS/WCDMA-2000/GPS, WLAN and WiMAX applications. A previous design was introduced in (2008) [4], which consists of a flared monopole with a sleeve for dual-band applications, it operates in two frequency bands 2.1 and 3.2 GHz covering DCS-1900/PCS/PHS,WCDMA/IMT-2000. This paper introduces a modified antenna consists of a single sided flared-slotted monopole with two “V”-shaped slotted sleeves for multiband applications. The proposed antenna is compact in size with overall dimensions 40mm×35mm. The modified antenna operates in four different bands: 1.58 GHz, 2 GHz, 2.5 GHz and 5 GHz covering DCS-1900/PCS/UMTS/WCDMA-2000/ GPS and 5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands. The antenna is fabricated on FR4 substrate with dielectric constant ε<sub>r</sub>=4.4 and thickness h=1.5 mm with a Finite Ground CPW (FGCPW) feeding structure. The measured and simulated return loss have a good agreement with each other. The proposed antenna provides nearly omnidirectional radiation characteristics.
    Microwave Conference Proceedings (APMC), 2010 Asia-Pacific; 01/2011
  • H.H. Awadalla, S.I. Shams, A. Amma
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    ABSTRACT: A novel design of an ultra wide band U-shaped monopole is presented and discussed. The antenna has a unique design consisting of a U shape with 2 additional arcs fed by a 50Ω microstrip feed. The antenna is low profile and has overall dimensions 30mm×30mm×1.5mm, which is compact in size for portable UWB applications. The simulated results show that the antenna has operating bandwidth (2.4-11.4GHz), satisfying the condition for ultra-wide band operation. The antenna exhibits band notch properties, and is able to prevent interference with the 5.2/5.8GHz WLAN and 5.5GHz WiMAX bands by varying the length of a small rectangle in the antenna structure. The symmetrical geometric structure of the antenna provides omnidirectional radiation patterns. The design criteria of this antenna as well as the outcome of the experimental results are presented in this paper. The antenna is fabricated and the return loss measured using a vector network analyzer. The measured and simulated results are in good agreement.
    Radio Science Conference (NRSC), 2011 28th National; 01/2011
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    ABSTRACT: Ultra-wideband antennas are used in many communications, medical and military applications. Several ultra-wideband antennas were studied before as radiating elements taking into consideration the return loss only without studying the group delay or the radiation efficiency. In these mentioned publications, the antennas were classified as ultra-wideband according to their satisfactory return loss over the required bandwidth. However neither the group delay nor the radiation efficiency was investigated. The group delay and the radiation efficiency are key elements to measure the antenna performance, as large group delay will lead to pulse dispersion which will put a limitation on the data rate, while low radiation efficiency indicates high losses in the antenna structure. In this paper two previously published antennas are re-investigated. The antennas are fabricated on FR4 substrate and there is a good agreement between the measured and simulated return loss. The antennas return loss indicates no significant reflections in the FCC defined band regarding the ultra-wideband Transmission Systems. The radiation efficiency curves are used to identify the power radiated by the antennas. Finally the delay profile has clarified the ability of the antennas to be used in high data rate communications with very short duration pulses.
    Antennas and Propagation (APSURSI), 2011 IEEE International Symposium on; 01/2011
  • Shoukry I. Shams, M. H. Sharaf, Ahmed Nafe, Mahmoud Nafe
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    ABSTRACT: The proposed approaches to deal with the antenna problems fall in two categories, the numerical solution and the analytical solution. Another technique to deal with the antenna problems is the equivalent TEM mode theory, introduced in 2002. This model considered the antenna to be an inner conductor of a fictitous open circuited lossy transmission line thus the propagation constant has to be complex with real part and imaginary part representing the attenuation constant α and the phase constant β respectively. However the values of the phase constant and the attenuation constant were tabulated and no closed form expressions or empirical formulas were provided and the procedure for extracting the model parameters was rather complicated and had no regular approach. These drawbacks were covered to a great extent in 2008, they provided a simple approach for extracting the model parameters in the case of center fed dipole antenna. The propagation constants were interpolated using the proper empirical formulas. However these empirical formulas were functions of the characteristic impedance Zo. The used approach was based on estimating the characteristic impedance Zo without showing it's effect on the results. These empirical formulas showed accurate results for the half wavelength antenna and all it's odd multiples, on the other hand they showed a significant deviation for the complete wavelength antenna and it's multiples. Moreover this model was not verified for other types of antennas. This paper verifies the model for the monopole antenna and the center fed dipole antenna with empirical formula for the characteristic impedance Zo to give accurate results for antennas with different electrical lengths.
    01/2011;
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    ABSTRACT: In this paper a novel antenna design is proposed for ultra-wideband (UWB) communication systems. The antenna consists of irregular pentagon monopole structured section with a 50Ω microstrip feeding structure. The simulation results show that the antenna's operating bandwidth from 3.1 to 12.9 GHz which is suitable for indoor high-data rate applications. The antenna provides omni-directional radiation patterns due to its symmetrical geometrical structure. The antenna has an overall size 44mm × 30mm. The antenna is fabricated on FR4 substrate with relative permittivity of 4.4 and thickness of 1.5mm and the measured results are in a good agreement with the simulated ones.
    Antennas and Propagation (MECAP), 2010 IEEE Middle East Conference on; 11/2010
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    ABSTRACT: This paper introduces a modified printed double sided triple-band and dual-sense circularly polarized patch antenna fed by a 50 Ω microstrip line loaded by a conductor rectangle. A previous design was introduced by Xiulong Bao & M. J. Ammann in 2008, it operates at 1.5 GHz and 2.6 GHz where the radiated fields are circularly polarized at these two bands. The proposed design in this paper is a modified version of the previously proposed one by adding a conductor rectangle at the end of the microstrip feed and etching three more slot arms in the ground. The modifications proposed in this paper enable the antenna to operate at three bands instead of two as in the previous design. This proposed antenna operates at the two bands of GPS systems (at 1.2 GHz and 1.575 GHz), and at the UMTS band (at 2.03 GHz). The radiation is circularly polarized at each band. For the first two bands the wave is RHCP while for the third band it is LHCP. A comprehensive numerical sensitivity analysis has been done to discuss the effects of various dimensional parameters and to optimize the performance of the designed antenna using an accurate simulation tool. The dielectric substrate used in the fabrication process is the FR4 material, of relative permittivity 4.4 and of thickness=1.5 mm. The fabricated antenna is measured in the microwave lab in the GUC. The simulated and measured results for the return loss show a good agreement.
    Microwave Symposium (MMS), 2010 Mediterranean; 09/2010
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    M.M. Azer, S.I. Shams, A.M.M.A. Allam
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    ABSTRACT: The article presents a compact double-sided printed omni-directional ultra wideband antenna operating within a band from 3.2 GHz to 12.2 GHz. The proposed antenna is fabricated on FR4 dielectric substrate and experimentally investigated. There is a good agreement between the measured return loss and the simulated one. The antenna gives symmetrical omnidirectional patterns.
    Antenna Technology and Applied Electromagnetics & the American Electromagnetics Conference (ANTEM-AMEREM), 2010 14th International Symposium on; 08/2010
  • A.A. Saeed, S.I. Shams, A.M.M.A. Allam
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    ABSTRACT: This article presents a design of a printed antenna with simply shaped radiator element for multi-operating bands of the wireless communication systems. With a simple design configuration including different U shapes on a printed FR4 substrate, the proposed antennas covering the GPS (1575 MHz), Mobile-WiMAX (3400-3600 MHz) and 5 GHz WLAN (5150- 5350/ 5725-5825 MHz) bands. Several properties of the proposed antennas in multiband operation, such as radiation pattern and measured return loss are numerically and experimentally investigated.
    Antenna Technology and Applied Electromagnetics & the American Electromagnetics Conference (ANTEM-AMEREM), 2010 14th International Symposium on; 01/2010
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    ABSTRACT: A novel design of a dual wide band branched chain monopole is presented and discussed. The antenna has a unique design consisting of a U shape with a center strip fed by a 50Ω microstrip line with the integration of branched chains in the appropriate places to achieve dual band operation. The antenna is low profile and has overall dimensions 42mm × 40mm, which is compact in size for portable applications. The simulated results show that the antenna operates at (1.2GHz-2.9GHz) and (5.1GHz-6.1GHz) which includes the following applications: DCS(1.71-1.88GHz)/PCS(1.85-1.99GHz)/UMTS(1.92-2.17GHz) cellular bands, the 2.4/5.2/5.8GHz WLAN bands and finally the 2.5/5.5GHz WiMAX bands. The symmetrical geometric structure of the antenna provides omnidirectional radiation patterns. The design criteria of this antenna as well as the outcome of the experimental results are presented in this paper. The antenna is fabricated and the return loss measured using a vector network analyzer. The measured and simulated results are in good agreement.
    Microwave Symposium (MMS), 2010 Mediterranean; 01/2010
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    ABSTRACT: Design of a compact circularly polarized antenna is introduced, which is a modification of previously proposed antenna with a similar shape. The first modification proposed in this paper is to decrease the original antenna dimension while operating at the same frequency 1.6 GHz. The second modification done is scaling down the first modified design to a final dimension of 2.4×2.4 cm2 in order to shift the band of operation to 2.0 GHz. The proposed antenna has a bandwidth from 1.965 GHz to 2.08 GHz the antenna is fabricated on an FR4 substrate material, and the measured results show a good agreement with the simulated ones .
    Antennas and Propagation (MECAP), 2010 IEEE Middle East Conference on; 01/2010