Ultra‐wideband and large‐range incident angles radar cross‐section reduction by quasi‐fractal polarisation conversion metasurfaces

Abstract

This study proposes a quasi-fractal polarisation conversion metasurface (PCM) for ultra-wideband radar cross-section reduction (RCSR). The simple and proposed metasurface is composed of double-heads arrowed-like unit cell benefited from the second iteration Koch fractal in its arm and cut-line to broaden the bandwidth. Consequently, this PCM unit cell and its 90, 180 and 270 degrees rotated counterparts obtain destructive interference cancellation between their reflected waves and RCSR. The proposed metasurface demonstrates 10-dB RCSR from 7.68 to 40.87 GHz (136.73%) for normal incident waves, and more than 96.7% up to 40 degrees incident angle that verifies the large range incident angle RCSR of the surface. The experimental measurement results at the normal incident angle and their comparison with simulation ones prove the idea.

The Experimental Method of Sparse Measurement Based on Target’s Radar Cross Section Data

“…With the development of information technology, detecting targets through radars is the main technical means used to identify targets, and the radar cross section (RCS) of the target represents the target's ability to reflect electromagnetic waves in the radar detection direction [1,2]. In the RCS testing system, especially for 360 degree rotation measurement of targets, the testing system needs to sample and measure the targets at different frequencies and azimuths.…”

“…where, c denotes the speed of light, L denotes the maximum size of the target, and fmax denotes the highest frequency. From equation (1), it can be seen that in microwave darkroom, for non blurry measurement of electrically large targets, there would be a significant amount of RCS data sampled in the frequency and azimuth domains. For example, tens of thousands of measurement points will be generated in the azimuth domain, while in the frequency domain measurement, in order to cover broadband's signal, there generates also tens of thousands of sampling frequency points.…”

Improving test efficiency based on sparse sampling and reconstruction for target's radar cross section

“…The radar cross section (RCS) of the target indicates the strength of the target's ability to reflect electromagnetic waves in the radar detection direction [1,2]. In the near-field RCS test system, especially in the super large-scale anechoic chamber, the 360 degree rotation measurement of the target has to be carried out.…”