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Pavel L. Mladyonov (1978). Leading engineer.

Pavel Mladyonov graduated from Kharkiv National University in 2000. He was post-graduate student in 2000-2003. Scientific leader was Prof. S.L. Prosvirnin. Now is principal engineer.

Research theme: Electromagnetic wave diffraction by the gratings of infinitely long complex shape strips

Diffraction characteristics of double-periodic gratings of perfectly conducting infinitely long strips having the complex shape are considered, using the method of moments. The gratings of metal strips can be supported by the dielectric (Fig.1b) or background substrates (Fig1.c). The shape strips within the periodic cell can be as symmetrical (Fig1d and Fig.1f) as well as no symmetrical (flat-chiral) (Fig.1a). Analyze of the reflection and transmission characteristics for the linearly and circular polarized incident plane electromagnetic wave is developed. The influence of strip shape changes and variation of parameters of dielectric substrate on frequency characteristics is analyzed. The possibility application of curvilinear metal strips supporting background substrates as high-impedance surface is considered.

Fig.1. The examples of gratings of infinitely long complex-shaped strips.

Grating supported the background substrate
If structure have shape of symmetrical meander within a periodically repeated cell (Fig.1d), then the argument of the reflection coefficients is varied resonantly closely range wave length which proportions the length strip on period of cell (Fig.2). Such resonances were not observed for the grating from straight strips (Fig.2). I want to draw your attention, to the fact that the property of the magnetic wall is realized and the impedance of surface is infinity when the argument of the reflection coefficient is passing zero.

Fig.2 Frequency dependence of argR for reflected grating.

Reflection from the grating supported the background substrate with nonzero imaginary part of permittivity shows potentially useful property – “loss amplification”. The high losses was predicted, using the method of moment, was observed in the experiment (the experimental results was measured at the University of Southampton [10]) and their sharp resonant character (Fig. 3).

Fig.3

If the strip gratings have chiral shape (Fig.1a) and the incident wave is linearly polarized along strip, the reflected wave is elliptically polarized and the parameters of the polarization ellipse is varied resonantly closely range wave length which proportions the length strip (Fig.4).

Fig.4 Frequency dependence of azimuth and ellipticity for reflected grating.

Gratings are supported by dielectric substrate
The frequency dependence of reflection and transmission coefficients of grating are resonance. The frequency dependence of reflection coefficient has points both of the total reflection as well as of the total transmission (Fig.5). As in the case grating are supported by background substrate, the chiral shape of grating strips reduce to variation parameters of the polarization ellipse of reflected and transmitted wave.

Fig.5 Frequency dependence of absolute value of reflection coefficient of grating with substrate.

Publications

1. S. L. Prosvirnin, S. A. Tretyakov, P.L. Mladyonov, ”Electromagnetic wave diffraction by plane periodic grating of wavy metal strips”, Proceedings DIPED-2001, Inst. for Applied Problems of Mechanics and Mathematics of NASU, Lviv, Ukraine, Sept. 18-20, pp. 11-15, 2001.
   
   Abstract: Numerical solution of electromagnetic wave diffraction by a two-periodic grating of wavy metal strips placed on dielectric substrate is obtained. The solution is verified for a particular case of straight strips by comparison with the rigorous solution. Frequency dependencies of the reflection coefficients are analyzed. Differences in reflection from classical one-periodic gratings of straight strips are mentioned.
   
   
2. S.L. Prosvirnin, S.A. Tretyakov, P.L Mladyonov. ”Electromagnetic wave diffraction by planar periodic gratings of wave metal strips.”, J of Electromagn. Waves and Appl., Vol. 16, No. 3, 421-435, 2002.
   
   Abstract: Numerical solution of electromagnetic wave diffraction by a two-periodic grating of wavy metal strips placed on dielectric substrate is obtained. The solution is verified for a particular case of straight strips by comparison with the rigorous solution. Analytical expressions for the reflection coefficients from wavy gratings in free space are obtained in the low frequency range. Frequency dependencies of the reflection coefficients are analyzed. Differences in reflection from classical one-periodic gratings of straight strips are discussed.
   
   
3. S.L. Prosvirnin, P.L Mladyonov, “Electromagnetic wave diffraction by the two-periodic grating of uninterrupted curvilinear metal strips.”, Radio Physics and Radio Astronomy, vol 7, ¹3, p.265-272, 2002 (in Russian).
   
   Abstract: Diffraction characteristics of a periodic grating consisting of strips having the shape of rounded meander, wavy or saw-shape lines are investigated using the method of moments. The analysis of the effects of total resonant reflection and transmission for the linearly polarized normally incident plane electromagnetic wave is performed in the case of one-mode regime. The comparison of reflection properties of two-periodic gratings with the classical plane grating of straight-line strips is presented.
   [PDF-263kb]
   
   
4. P.L. Mladyonov, "Electromagnetic wave diffraction by a double-layer periodic grating of curvilinear metal strips", Proceedings of 9-th International Conference on mathematical methods in electromagnetic theory, Sept. 10-13, 2002, Kiev, Ukraine, vol.2, p.395-397, 2002.
   
   Abstract: Reflection and transmission characteristics of double-layer two-periodic gratings of perfectly conducting infinite strips with a complex shape are considered. The structures with layers that have strips turned on 90 degrees and parallel are considered. The comparison of reflection properties of double-layer two-periodic gratings of straight-line strips with curvilinear ones is presented.
   
   
5. P. Mladyonov , S. Prosvirnin , S. Tretyakov, S. Zouhdi, “Planar Array of Microstrip as Thin resonant Magnetic Wall”, Proceedings of the 2003 AP-S/URSI conference, Ohio, 2003, vol. 2, pp. 1103-1106.
   
   
6. P.L. Mladyonov, S.L. Prosvirnin, “Microstrip Doubly-Periodic Grating of Continuous Curvilinear Metal Strips as a High-Impedance Surface”, Telecommunications and Radio Engineering, 63(2), pp. 109-118, 2005.
   
   Abstract: Diffraction characteristics of a periodic grating consisting of strips having the shape of rounded meander, wavy or saw-shape lines are investigated using the method of moments. The analysis of the effects of total resonant reflection and transmission for the linearly polarized normally incident plane electromagnetic wave is performed in the case of one-mode regime. The comparison of reflection properties of two-periodic gratings with the classical plane grating of straight-line strips is presented.
   
   [PDF-110kb]
   
   
7. P. Mladyonov, Electromagnetic wave diffraction by the microstrip two-periodic grating of curvilinear metal strips having chiral shape, 11th Int. Student Seminar on Microwave Applications of Novel Physical Phenomena 2004, June 7-9, St. Petersburg, Russia, p. 24-26.
   
   [PDF-260kb]
   
   
8. P. Mladyonov , S. Prosvirnin , S. Zouhdi, “Regular gratings of planar strips as high impedance surfaces”, Progress in Electromagnetic Research Symposium 2004, Pisa, Italy March 28-31 (Invited presentation), pp. 569.
   
   [PDF-10kb]
   
   
9. P.L. Mladyonov, “Electromagnetic wave diffraction by the microstrip two-periodic grating of chiral metal strips”, “Conference Proceedings MMET-2004”, Dniepropetrovsk, Ukraine, Sept. 14-17, vol.1, p.513-515, 2004.
   
   Abstract: Reflection characteristics of microstrip two-periodic gratings of perfectly conducting infinitely long strips having the complex shape are considered. The effect when reflected field possess orthogonal polarization relative to incidence wave polarization is considered. The possibility of insertion the control device in strips for the transformation considered grating to the array from the strip disconnected elements is proposed. The possibility for the structure application as high-impedance surface is considered. The comparison of the reflection properties of the two-periodic gratings of non-chiral strips and straight-line strip gratings is presented.
   
   
10. V.A.Fedotov, P.L.Mladyonov, S.L.Prosvirnin, N.I. Zheludev, “ Planar electromagnetic metamaterial with a fish scale structure”, Physical Review E. 72, 056613 (2005) (4 pages).
    
    Abstract: We report on a continuous electromagnetic metal planar metamaterial, which resembles a “fish scale” structure. Apart from the one isolated wavelength, it is highly transparent to electromagnetic radiation through-out a broad spectral range and becomes completely “invisible” at some frequency inflicting to transmission losses and phase delay. When the structure is superimposed on a metallic mirror it becomes a good broadband reflector everywhere apart from one wavelength where the reflectivity is small. At this wavelength the reflected wave shows no phase change with respect to the incident wave, thus resembling a reflection from a hypothetical zero refractive index material, or “magnetic wall”. We also discovered that the structure acts as a local field concentrator and a resonant “amplifier” of losses in the underlying dielectric.
    [PDF-490kb]
    
    
11. V. A. Fedotov, A. V. Rogacheva, N. I. Zheludev, P. L. Mladyonov, and S. L. Prosvirnin, “Mirror that does not change the phase of reflected waves”, Appl. Phys. Lett. 88, 091119 (2006) (3 pages).
    
    Abstract: We report that electromagnetic wave reflected from a flat metallic mirror superimposed with a planar wavy metallic structure with subwavelength features that resemble “fish scale” reflects like a conventional mirror without diffraction, but shows no phase change with respect to the incident wave. Such unusual behavior resembles a reflection from a hypothetical zero refractive index material, or “magnetic wall”. We also discovered that the structure acts as a local field concentrator and a resonant “amplifier” of losses in the underlying dielectric.
    [PDF-370kb]
    
    

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