Publication Date:
2019
Description:
Abstract
A planar array of dipoles with matched loads in air backed by a ground plane at a quarter wavelength would become an absorber with a −10‐dB bandwidth of about 10%. Obviously, if the air substrate behind the dipoles is replaced by a dielectric substrate, the physical thickness of the absorber, saying a quarter wavelength, can be reduced. Meanwhile, as the incident waves illuminate on the absorber, the reflections are mainly from three ways, which are the air‐dielectric interface, the back scattering of the loaded dipole as a receiving antenna, and the ground plane. This paper shows that with the combination of the three reflections and a suitable dielectric constant together with its dipole separations, the −10‐dB bandwidth of the absorber increases to 20% and beyond. To further decrease the thickness of the dipole‐based absorber, inductive ground plane is introduced to replace the normal ground; phase analyses of the dipole‐based absorber with inductive ground is also given to explain the feasibility of the proposed technique. Both simulations and measurement results show that, with the proposed technique above, not only the thickness of the dipole‐based absorber can be decreased from a quarter wavelength to less than fifth wavelength, but also the −10‐dB bandwidth of the reflection can be enhanced from 20% to 48% or so.
Print ISSN:
0048-6604
Electronic ISSN:
1944-799X
Topics:
Geosciences
,
Physics
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