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An HIS with nonidentical lattices and its reflection properties are investigated and discussed. Using a linear reflection phase gradient from pi/2 to pi/2 with pi10 step with unit cell index across face, the surface can steer a reflected beam to 20.2deg in thetas. The pattern of the electromagnetic field reflected with the normally incident y-polarized wave is analyzed and experimented.
In the paper, we have shown that in order to reduce influence of reflection waves, it is useful to average the radiation patterns which are measured by changing the distance between two antennas. The results using photonic balun are almost the same as those of the conventional balun. Because the presence of the coaxial cable does not affect the horizontal pattern measurements. We will apply the proposed...
A Vivaldi TSA array has been designed and analysed. It can operate over 4-16GHz and be capable of scanning to 50deg. This study shows that the strong mutual coupling between elements plays a constructive role in the array performance of active impedance matching. The introduction of corrugated edge to the TSA element has no effect on the active matching but the scan gains are improved. Further research...
In this paper, we take up mushroom type EBG structures and clarify the frequency-band-rejection characteristics of the finite EBG structures on the finite ground plane, and we also compare that with the infinite EBG structures and the semi-infinite EBG structures. Here, we analyze the reflection characteristics of a normal incidence plane wave.
EBG (electromagnetic bandgap) structures have lately attracted considerable attention both for the surface wave reduction and low profile antennas. One of the most remarkable features of EBG structures is their periodicity. Brillouin pointed out the bandgap phenomena by the periodic structure early in the 20th century. Indeed, the surface wave reduction by EBG structures is explained in the same way...
In recent years, the metamaterials and its applications to antenna and other fields have been widely investigated theoretically and experimentally. The metamaterials are usually realized by some periodic structures composed of a conductor and/or dielectric/magnetic materials. In order to design the characteristics of metamaterial properly, some theoretical and/or numerical techniques are required...
In evaluating the performance of the small antenna, one of the most important parameters is the radiation efficiency as well as the radiation power. If the input power of the antenna is measured, the radiation power can be determined by multiplying the radiation efficiency by the input power. One of the techniques for measuring the radiation efficiency is the pattern integral method which needs a...
This paper defines an energy-based pulse reflection coefficient and a corresponding pulse matching ratio for the characterization of ultra-wide band antennas. As opposed to the usual frequency-domain reflection coefficient or VSWR, the proposed descriptors provide a relevant view on the amount of energy that is sent back to the transmitter. In order to evaluate the pulse reflection coefficient time-domain...
In this paper, we report our experimental and numerical results, confirming the phenomenon of dual in-phase reflection, i.e. dual-resonant behavior, for a TM-polarization plane wave oblique incidence on the conventional mushroom-like EBG structures. A modified local resonance cavity (MLRCC) model of EBG structures has been presented to explain the essential features of dual- resonant behavior and...
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