Analysis and Design of Checkerboard Leaky-Wave Antennas With Low Radar Cross Section

Abstract

This paper addresses the analysis and design of a new class of metasurface leaky-wave antennas (LWAs) that inherently have low monostatic radar cross section (RCS) for normal incidence parallel polarization. The impedance profile of these antennas is modulated with a square wave to achieve leaky-wave behavior with low RCS. The low RCS performance is justified by the concepts of generalized Snell's law of reflection and array theory. When the reflection phase difference between consecutive periods is near 180°, the power reflected in the specular direction is minimal. It is also shown that modulating the surface impedance with a square wave still results in a high-gain fan beam similar to that of a sinusoidal modulation; however, the trade-off for obtaining a low RCS is an increase in the sidelobe level due to radiation from higher-order harmonics. A similar trade-off exists between the gain/beamwidth and RCS reduction. A prototype of an LWA with low RCS was fabricated and measured; an excellent agreement was observed between simulations and measurements.

Keywords

• Anomalous reflection
• checkerboard surfaces
• diffraction grating
• diffraction modes
• generalized Snell’s law
• impedance modulation