Wide‐field circular SAR imaging: An empirical assessment of layover effects

Abstract

Radiation patterns in Figure 7(b) show that design B exhibits the low cross polarization level of 222 dB, conversely, design A and C has cross polarization level of 215 dB. In addition, ABSTRACT: In circular synthetic aperture radar (CSAR), targets are usually scanned over the complete azimuthal aperture of 360 . A major challenge inhibiting successful CSAR image production is encountered in two-dimensional imaging of relatively large scenes (i.e. wide-field scenarios). For such cases, the spatially variant radar signature gives rises to image degradations known as layover effects. In this paper, the imaging results for hypothetical and real complex targets using their CSAR data at C band are demonstrated to characterize these effects. In real experiments, a ground-based, outdoor CSAR system is exploited thanks to the circular balcony of a building that provides 270 view of targets. A spherical back-projection algorithm is used to focus near-field data and the reconstructed images are also cleaned out from clutter to more easily visualize the layover artifacts.ABSTRACT: In this article, a wideband monopole antenna with band notched reconfigurability is proposed. The antenna consists of a wideband monopole antenna, incorporated with reconfigurable electromagnetic bandgap (EBG) structures. Six EBG structures with different band notched frequency are used to achieve six band notched reconfigurations. The EBG structures are placed underneath the feed line of the antenna. A switch is placed at each EBG structure, and by controlling the state of the switch, the band notched operation of the EBG can be activated or deactivated. The proposed antenna is capable to provide useful features for the notched band UWB communication system. V C 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:497-501, 2015; View this article online at wileyonlinelibrary.com.

Anechoic chamber measurements for circular isar imaging at Mersin University’s Meatrc Lab

“…However, the responses also include ring-shaped defocusing signatures centered at the cylinders' exact locations. These can be well attributed to the layover phenomenon as encountered in 2D imaging of a 3D target under wide azimuthal viewing (Demirci, et al 2015). Moreover, the scattering interactions can also be noticed from the low-level returns located between the two cylinders.…”

Analysis of Dual- and Full-Circular Polarimetric SAR Modes for Rice Phenology Monitoring: An Experimental Investigation through Ground-Based Measurements

“…Figure 5 shows the reconstructed images of one sample of data observed on 30 August 2016, for LL, RL, and RR polarizations. A spherical back-projection algorithm is used to process this wide-angle data [28]. From the reflectivity images in Figure 5, it can be clarified that all rice stocks are clearly identified for each polarization thanks to the high-resolution capability of our system.…”

CFAR based morphological filter design to remove clutter from GB‐SAR images: An application to real data

“…In order to discover the capability of MF in radar images; it should be employed after a basic clutter removing procedure. For this purpose, CFAR detector is a good choice for basic removing undesired clutter.…”