Dual-Polarized Band-Absorptive Frequency-Selective Rasorber With Narrow Transition Band Based on a Multilayer Open Circular Cavity Truncated Cone

This communication proposes a dual-polarized band-absorptive frequency-selective rasorber (BA FSR) with high selectivity. By layering multilayer open circular cavities (OCC) with a gradient radius, a multilayer OCC truncated cone unit cell is created. The transmission, absorption and dispersion characteristics of the single-layer OCC array, the multilayer OCC array with an equal radius and the proposed multilayer OCC array with a gradient radius are all analyzed in detail. In addition, the operation modes of transmission poles and absorption peaks are investigated. The measured results reveal a decent lowpass band with
$\vert S_{11}\vert \le -10$
dB, a narrow transition band with
$FR_{\mathrm {ap}}$
= 1.06, and a wide absorption band with a fractional bandwidth (FBW) of 65.8% for the prototype. Additionally, it exhibits a stable stealth performance within the ±30° airspace range.