Browsing by Author "Joubert, Johan"

Browsing by Author "Joubert, Johan"

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  • Accurate gain measurements for large antennas using modified gain-transfer method 
    Mayhew-Ridgers, Gordon; Van Jaarsveld, Paul A.; Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Institute of Electrical and Electronics Engineers, 2014)
    The classic gain-transfer method assumes a uniform plane wave incident over the apertures of the gain-transfer standard (typically a standard-gain horn) as well as the antenna under test. Variations in the incident field ...
  • Active calibration target for bistatic radar cross-section measurements 
    Pienaar, Monique; Odendaal, J.W. (Johann Wilhelm); Joubert, Johan; Cilliers, J.E.; Smit, J.C. (American Geophysical Union (AGU), 2016-05)
    Either passive calibration targets are expensive and complex to manufacture or their bistatic RCS levels are significantly lower than the monostatic RCS levels of targets such as spheres, dihedral- and trihedral corner ...
  • An active wideband reference target for the calibration of ground to air radar systems 
    Pienaar, Monique; Odendaal, J.W. (Johann Wilhelm); Cilliers, Jacques E.; Kloke, Kevin Hugh; Joubert, Johan (Wiley, 2016-05)
    The radar cross section (RCS) of passive calibration targets is relatively low, which leads to a commensurate increase in the uncertainty of the radar’s calibration. To address this deficiency, an active radar calibration ...
  • Analysis and design of a wide band omnidirectional antenna 
    Jacobs, Ockert Botha; Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Wiley, 2011-06)
    The analysis and design of an omni-directional antenna that functions over a very broad frequency band is presented. Design guidelines for this antenna have been derived using electromagnetic analysis software. ...
  • Anomalous reflection from a phase gradient metasurface with arbitrary incident angle 
    Barnard, Wihan; Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Institute of Electrical and Electronics Engineers, 2023-02)
    A planar phase gradient metasurface (PGM) with phase gradients in two in-plane directions will introduce two additional wave vectors to the reflected wave vector. For small incident angles, close to the normal vector, the ...
  • Antenna with a reactive impedance substrate for mine rescue applications 
    Roestorff, Martin; Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Wiley, 2019-01)
    Two electrically small, reactive impedance surface (RIS) backed, antennas are presented that can be used by rescue workers to locate miners in emergency situations in underground mines. One antenna was designed for optimum ...
  • Bistatic RCS measurements of large targets in a compact range 
    Potgieter, Monique; Odendaal, J.W. (Johann Wilhelm); Blaauw, Ciara; Joubert, Johan (Institute of Electrical and Electronics Engineers, 2019-04)
    This communication illustrates the ability to perform bistatic radar cross-section (RCS) measurements at a fixed bistatic angle in a compact range. Literature regarding bistatic RCS measurements in compact ranges is limited. ...
  • A broadband 180° hybrid ring coupler using a microstrip-to-slotline inverter 
    Ferreira, Riaan; Joubert, Johan (Wiley, 2015-09)
    A new broadband 180° hybrid ring coupler with a Chebyshev return loss response, implemented in microstrip line, and a phase inverter using microstripto- slotline transitions, is presented. The transitions were constructed ...
  • Coaxial end-launched and microstrip to partial H-plane waveguide transitions 
    Kloke, Kevin Hugh; Joubert, Johan; Odendaal, J.W. (Johann Wilhelm) (Institute of Electrical and Electronics Engineers, 2015-10)
    Conventional rectangular waveguides are commonly used for high power and other microwave and millimeter-wave applications. Their use at lower frequencies has been limited by their bulky nature. A new type of compact ...
  • Compact 0.5–18 GHz double‐ridged guide horn antenna 
    Jacobs, Bennie; Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Wiley Open Access, 2021-03)
    Broadband double‐ridged guide horn (DRGH) antennas are extensively used in antenna measurement and electromagnetic compatibility and interference testing, especially the 1– 18 GHz DRGH antenna which is widely accepted as ...
  • A compact dual-circularly polarized cavity-backed ring-slot antenna 
    Ferreira, Riaan; Joubert, Johan; Odendaal, J.W. (Johann Wilhelm) (Institute of Electrical and Electronics Engineers, 2017-01)
    A low profile dual-circularly polarized printed ring-slot antenna with a small footprint, which radiates above an open cavity loaded with an artificial magnetic conducting reflector, is presented. The feed network ...
  • CPW-fed cavity-backed slot radiator loaded with an AMC reflector 
    Joubert, Johan; Vardaxoglou, J.C.; Whittow, W.G.; Odendaal, J.W. (Johann Wilhelm) (Institute of Electrical and Electronics Engineers, 2012-02)
    A low profile coplanar waveguide (CPW) fed printed slot antenna is presented with uni-directional radiation properties. The slot antenna radiates above a closely spaced artificial magnetic conducting (AMC) reflector ...
  • Design of center-fed printed planar slot arrays 
    Potgieter, Llewellyn; Joubert, Johan; Odendaal, J.W. (Johann Wilhelm) (European Microwave Association, 2015)
    Adesign approach for printed planar slot array antennas is presented. The antenna array consists of half-wavelength slot radiators positioned on a rectangular grid, and a slotline feed network. Three planar slot array ...
  • Design of compact planar rat-race and branch-line hybrid couplers using polar curves 
    Joubert, Johan; Odendaal, J.W. (Johann Wilhelm) (Wiley, 2015-11)
    An approach where polar curves are used to miniaturize hybrid couplers is presented. The design of such couplers can be done with the optimization of a few parameters using full-wave analysis software. The results show ...
  • A dipole with reflector-backed active metasurface for linear-to-circular polarization reconfigurability 
    Van Aardt, Ruan; Joubert, Johan; Odendaal, J.W. (Johann Wilhelm) (MDPI, 2022-04)
    In recent years, significant advances have been made in diversifying the capabilities of communication systems by using reconfigurable antennas. There are many types of reconfigurable antennas—to achieve pattern, frequency, ...
  • DRGH antenna with improved gain and beamwidth performance 
    Gerber, Monique; Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Institute of Electrical and Electronics Engineers Inc, 2020-05)
    Double-ridge guide horn (DRGH) antennas are widely used in antenna and EMC testing facilities as feed antennas and gain transfer standards. Increasing the low-frequency gain to obtain a more constant 3 and 10 dB beamwidth, ...
  • Dual-band dual-polarized array for WLAN applications 
    Steyn, J.M.; Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (EMW Publishing, 2009)
    This paper presents a dual-band dual-polarized antenna array design for WLAN applications. Four double-dipole elements are orthogonally interleaved to facilitate operation in both the standard WLAN frequency bands (IEEE ...
  • Elliptically shaped quad-ridge horn antennas as feed for a reflector 
    Jacobs, Ockert Botha; Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Institute of Electrical and Electronics Engineers, 2011)
    Quad-ridge horn antennas of various geometries are considered as possible candidates for a wideband reflector antenna feed. It is demonstrated that shaping the sidewalls of the ridge horns significantly improves the ...
  • Experimental simulation of retrodirective cross-eye jamming 
    Du Plessis, W.P. (Warren Paul); Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Aerospace & Electronic Systems Society, 2011-01)
    Experimental measurements that accurately simulate the effect of a retrodirective cross-eye jammer on a monopulse radar are described. The accuracy of a recently published extended analysis of retrodirective cross-eye ...
  • Extended analysis of retrodirective cross-eye jamming 
    Du Plessis, W.P. (Warren Paul); Odendaal, J.W. (Johann Wilhelm); Joubert, Johan (Institute of Electrical and Electronics Engineers, 2009-09)
    An extended and rigorous analysis of retrodirective cross-eye jamming in a radar system scenario is presented. This analysis removes the approximations that limit the validity of other analyses of cross-eye jamming. These ...