The Grounded Dielectric Slab as a Planar Leaky-Wave Applicator.

1990 ◽  
Vol 189 ◽  
Author(s):  
G. D'ambrosio ◽  
G. Ferrara ◽  
R. Massa
Keyword(s):  
Decay Rate ◽  
Free Space ◽  
Point Of View ◽  
Deep Processing ◽  
Dielectric Slab ◽  
Leaky Wave ◽  
Antenna Theory ◽  
Leaky Wave Antenna ◽  
Wave Antenna ◽  
Space Case

It is well known that a leaky wave in free space may show a decay rate even less than zero, or, in other words, its amplitude may grow instead of decay [1,2,3,4]. The above behaviour is very attractive from the point of view of deep processing of materials [5,6]; thus we extended the leaky-wave antenna theory to the lossy (half) space case and analyzed in detail the channel guide applicator [7,8,9].

Leaky wave antenna based on image NRD guide with staircase-shaped dielectric slab

2000 ◽  
Vol 36 (13) ◽  
pp. 1102 ◽  
Author(s):  
M.T. Lee ◽  
K.M. Luk ◽  
S.J. Xu ◽  
E.K.N. Yung
Keyword(s):  
Dielectric Slab ◽  
Leaky Wave ◽  
Leaky Wave Antenna ◽  
Wave Antenna ◽  
Nrd Guide

scholarly journals Design of leaky-wave antennas with transverse slots for end-fire radiation with optimized radiation efficiency

2019 ◽  
Vol 17 ◽  
pp. 71-75
Author(s):  
Thomas Vaupel ◽  
Claudius Löcker
Keyword(s):  
Modal Analysis ◽  
Free Space ◽  
Waveguide Mode ◽  
Wave Mode ◽  
Main Beam ◽  
Attenuation Constant ◽  
Leaky Wave ◽  
Leaky Wave Antenna ◽  
Wave Antenna ◽  
Phase Constant

Abstract. A substrate integrated waveguide (SIW) with transverse slots on the top plane can be used to design an effective leaky-wave antenna with good frequency beam-scanning and platform integration capability. For a main beam near end-fire, the phase constant of the radiating wave must be near to the free space wavenumber or slightly larger. In this context, the modified Hansen-Woodyard condition gives an optimum phase constant to maximize the directivity at end-fire. For the analysis of the wave propagation we have implemented a modal analysis for rectangular waveguides with transverse slots. Near end-fire, three types of modal solutions exists, a leaky improper mode, a surface wave mode and a proper waveguide mode. The leaky mode can reach phase constants larger than the free space wavenumber to fulfill the Hansen-Woodyard condition, but loses strongly its physical significance in this slow wave region, thus the excitation of the leaky-wave becomes negligible there, whereas the proper waveguide mode is dominant but exhibits only a negligible radiation loss leading to a strong drop of the antenna efficiency. Therefore, the optimum efficiency of 86 % for maximizing the gain as proposed in the literature cannot be reached with this kind of leaky wave antenna. But it will be shown in this contribution by analyzing antenna structures with finite aperture lengths, that the efficiency can reach nearly 100 % if the phase constant of the leaky-wave meets exactly the free space wavenumber (ordinary end-fire condition) and the aperture length is adjusted with regard to the attenuation constant of the leaky-wave from the modal analysis. For a given aperture length, a procedure is outlined to adjust the attenuation constant in several steps at the desired ordinary end-fire frequency to reach maximum gain and efficiency.

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