On the Influence of Coupling Amc Resonances for RCS Reduction in the SHF Band

Abstract

Abstract-A novel approach to Radar Cross-Section reduction using a thin Artificial Magnetic Conductor (AMC) structure is presented. The novel AMC structure combines two unit-cell metallization sizes and so it presents two resonant frequencies. RCS reduction is based on destructive interference of two partial reflections. Taking as starting point a previous work showing significant RCS reduction based on the combination of two AMC surfaces with overlapped AMC operation bandwidths (so that they have similar reflection coefficient amplitude) without a 180 • -phaseshift, the key point of this contribution is to analyze the influence of the degree of the aforementioned overlapping on RCS reduction and to show that this achievement is based on coupling phenomena. A comparison of the achieved RCS reduction when combining two AMCs whose AMC operation bandwidth overlaps, two AMCs with non-overlapped AMC operation bandwidths, and PEC-AMC is presented. Prototypes of these three combinations have been manufactured (having them the same size) and their RCS has been measured in an anechoic chamber.

Broadband Radar Cross-Section Reduction for Microstrip Patch Antenna Based on Hybrid Amc Structures

“…Comparing Figure 1 and Figure 2, the AMC element 1 resonant frequency is 5 GHz and that of AMC element 2 is 7 GHz. The reflection phase from 90 • to −90 • of two AMC structures is not overlapped, and a broadband RCS reduction can be obtained by arranging these AMC unit cells properly around the patch antenna [16]. Figure 3 shows the reference antenna with a central frequency of 4.5 GHz.…”

“…In order to overcome the intrinsic narrow bandwidth of AMC structure, two AMC structures based on [16,17] are designed, which operate at two different resonance frequencies without overlapped operation bandwidths. The chessboard configuration is used to arrange the AMC unit cells in [15] for reducing the RCS of metal plate, which is different from the design in this paper.…”

“…In [13], the mushroom-like EBG was used to reduce RCS of the patch array antenna, and one UC-EBG acted as the ground plane of printed dipole antenna to reduce out-of-band RCS in [14]. A combination of two AMC structures with overlapped operation bandwidths was used to cancel out the backscatter energy in [15], and this method is based on the coupling resonances phenomena [16]. However, these approaches are shown to work well in the normal direction over a relative narrowband.…”

Efficient Classification of Low-Resolution Range Profiles of Automobiles Using a Combination of Useful Features

“…Among several radar signatures, the range profile (RP) shows the unique one dimensional distribution of the radar cross-section [2][3][4][5][6][7][8][9] of the automobile and can be effectively used for classification of automobiles which can contribute to anti-collision, lane-change, and automobile control regardless of weather and day-night conditions [10]. RP can also provide two-dimensional radar image of automobiles if the synthetic aperture radar (SAR) [11][12][13][14][15][16][17][18], the inverse SAR [19] and the jet engine modulation [20] techniques are applied.…”

Artificial Magnetic Conductors on Wideband Patch Antenna

“…AMCs are used in low-profile microstrip antennas to generally improve their gain and bandwidth [3,4] and directivitity [5]. Usually AMC cells are fabricated as periodic structures.…”