• Effect of feedback carrier excitation on LED external quantum efficiency 

      Autor: Kučera, L.; Macháč, J.; Míšek, J.
      (IEEE, 1982-02)
      Self-absorption of photons generated by prior luminescence processes affects both the steady-state and transient characteristics of LEDs. In this study we confine ourselves to one of the most important steadystate ...
    • Evaluation and Correction of Cable Phase Stability in High Frequency Near-Field Measurement 

      Autor: Vancl, Jan; Černý, Petr; Škvor, Zbyněk; Mazánek, Miloš
      (IEEE, 2008-04)
      In case of the near-field measurement, the radiated field by the measured antenna is received by two- dimensional scanner in defined points. During the process of the field scanning, the cable between the VNA and the scanner ...
    • Even and Odd Modes on a Conductor-Backed Slotline 

      Autor: Zehentner, Ján; Macháč, Jan; Mrkvica, Jan
      (IEEE, 2002-09)
    • Evolution of New Real and Complex Improper Solutions of the Slotline Dispersion Equation 

      Autor: Zehentner, J.; Macháč, J.; Migliozzi, M.
      (IEEE, 1997-09)
      An attempt is made in this paper to reach a better understanding of the behaviour of open uniplanar circuits, particularly the slotline. A new second leaky wave has been revealed in addition to the dominant bound and leaky ...
    • First results of microwave measurement of broadband radio interference filters 

      Autor: Hoffmann, Karel; Škvor, Zbyněk
      (IEEE, 2004-12)
      A vector measurement method for testing multiport interference filters for shielded chambers has been used. Measured data up to 3 GHz are presented. The authors believe that this is the first time such results have been published.
    • Flat Waveguide with a Longitudinal Slot 

      Autor: Zehentner, Ján; Mrkvica, Jan; Macháč, Jan
      (IEEE, 2005-06)
      This paper presents an analysis of a flat slotted waveguide by the spectral domain method finalized by a complex root search procedure. Matching of fields from bounded and unbounded regions at the common interface is ...
    • Hidden Problems in Precise Calibration on Microstrip 

      Autor: Raboch, Jiří; Hoffmann, Karel; Škvor, Zbyněk; Hudec, Přemysl
      (IEEE, 2008-12)
      A study of calibration problems on microstrip with respect to interaction of electromagnetic fields around SMA to microstrip launcher and microstrip short was carried out in frequency band up to 26 GHz. Omni Spectra SMA ...
    • Isotropic Epsilon-Negative Particles 

      Autor: Macháč, Jan; Protiva, Pavel; Zehentner, Ján
      (IEEE, 2007-06)
      This paper presents two particles with negative permittivity in some frequency band. The response of a single dipole loaded by an inductance is strongly anisotropic. The response of a spider dipole does not depend on the ...
    • Leakage Effects of Dominant and Higher Order Modes on Slotline 

      Autor: Macháč, Jan; Zehentner, Jan
      (IEEE, 1996-09)
      The properties of the slotline when the dominant bound or leaky wave propagates, together with the behaviour of new higher order modes are investigated. The frequency range in which the slotline transmits the bound wave ...
    • Leaky Wave Radiation of a Printed Slotline Antenna 

      Autor: Zehentner, Ján; Macháč, Jan; Lorenz, Petr; Mrkvica, Jan
      (IEEE, 2001)
      This paper presents a theoretical prediction of the field radiated from a uniplanar slotline antenna operating with the leaky wave. Discussion on a possible spectrum of space leaky waves is opened. Several antennas and ...
    • Left-Handed Coplanar Waveguide 

      Autor: Macháč, Jan; Hudlička, Martin; Zehentner, Ján; Spiliotis, Nikolaos G.; Omar, Abbas S.
      (IEEE, 2005-06)
      This paper proposes a new version of a left-handed coplanar waveguide. The line has a fully uniplanar structure without vias and lumped elements. The series capacitors are represented by interdigital capacitors and the ...
    • Load Impedances of Complex Slotline Terminations 

      Autor: Macháč, J.; Zehentner, J.; Menzel, W.
      (IEEE, 1995-09)
      Single slotline has gained new interest due to application in uniplanar circuits, antennas or active radiators, all these including slotline short circuits or even more complex terminations. This paper gives a new approach ...
    • Low Profile Slotted Flat Waveguide Leaky Wave Antenna 

      Autor: Zehentner, Ján; Macháč, Jan; Zabloudil, Pavel
      (IEEE, 2006-06)
      This paper presents the application of a flat waveguide with a longitudinal slot in the middle of its wider wall for the design of a leaky wave antenna. The antenna radiates into one relatively narrow main beam and its ...
    • Microstrip Line on an Artificial Dielectric Substrate 

      Autor: Macháč, Jan
      (IEEE, 2006-07)
      This letter presents a new version of an artificial dielectric substrate and a microstrip line built on top of this substrate. The substrate is fabricated as a two-dimensional array of metallic posts separated from the top ...
    • Microwave reflectivity from gold sputtered nanolayer 

      Autor: Buchar, Pavel; Macháč, Jan; Zehentner, Ján
      (IEEE, 2007-11)
      This paper deals with reflectivity of a gold layer of nanometer-scale thickness sputtered on a dielectric foil at microwave frequencies. A model of nanometer-scale spheres characterizes the behavior of the layer. For short ...
    • Modes on the Standard and Inverted Conductor-Backed Slotline 

      Autor: Zehentner, Ján; Macháč, Jan; Mrkvica, Jan; Tuzi, Carlo
      (IEEE, 2003-06)
      This paper recalls modes which can propagate on the conductor-backed slotline. The characteristic of the dominant mode on the CBSL is documented. The ICBSL is a modification of the CBSL placed in a dielectric with permittivity ...
    • New Bulk Metamaterial 

      Autor: Macháč, Jan; Buchar, Pavel; Zehentner, Ján; Omar, Abbas S.
      (IEEE, 2005-10)
      The design, analysis, fabrication and measurement of a new bulk metamaterial is reported in this paper. The structure of the new medium is made up of left-handed parallel strips. The series capacitors are realized by short ...
    • New Space Leaky Wave Spectrum Components on the Slotline 

      Autor: Zehentner, Ján; Macháč, Jan
      (IEEE, 2000-10)
      Surface and space leakage of power deteriorates the operation of circuits. On the other hand space leaky waves enable the design of specific radiators. In this paper we therefore investigate the potential of the slotline ...
    • Novel Entire Top Surface Planar Leaky Wave Antenna 

      Autor: Zehentner, Ján; Macháč, Jan; Zabloudil, Pavel
      (IEEE, 2007-10)
      This paper presents the application of a flat waveguide with a longitudinal slot in the middle of its wider wall for the design of a leaky wave antenna. The antenna is fed from a coaxial connector on its bottom, and provides ...
    • Novel Selected Modes on the Conductor - Backed Slotline 

      Autor: Zehentner, Ján; Macháč, Jan; Mrkvica, Jan
      (IEEE, 2002)
      This paper presents a detailed full-wave analysis of the conductor-backed slotline. The occurrence of an even dominant mode is revealed. This mode may propagate alone from dc up to the frequency at which the first leaky ...