Design, fabrication, and characterization of lightweight and broadband microwave absorbing structure reinforced by two dimensional composite lattice

Abstract

Microwave absorbing structures (MASs) reinforced by two dimensional (2D) composite lattice elements have been designed and fabricated. The density of these MASs is lower than 0.5 g/cm 3 . Experimental measurements show that the sandwich structure with glass fiber reinforced composite (GFRC) lattice core can serve as a broadband MAS with its reflectivity below −10 dB over the frequency range of 4-18 GHz. The low permittivity GFRC is indicated to be the proper material for both the structural element of the core and the transparent face sheet. Calculations by the periodic moment method (PMM) demonstrate that the 2D Kagome lattice performs better for microwave absorbing than the square one at relatively low frequencies. The volume fraction and cell size of the structural element are also revealed to be key factors for microwave absorbing performance.

Hybrid lattice-core sandwich composites designed for microwave absorption

“…The total thickness of the grid panel is 18 mm. Porosity and thickness of the design panel, close to those of the finished experiments of Fan et al [10] and Chen et al [11], guarantee the radar absorption.…”

“…Due to the volume fraction is usually smaller than 0.1, the lattices have limited influence to the absorbing behaviors of the filled foams. This point has also been testified by Fan et al [10] and Chen et al [11]. As the frequency increases, contributions of the high order mechanism are more and more important.…”

“…Larger thickness promotes the microwave absorption. For usual foams, the thickness is suggested to be larger than 15 mm based on the experiments achieved by Fan et al [10] and Chen et al [11].…”

“…The experiments suggested that grid panels of 18 mm and 20 mm thickness should be better than other panels of 13 mm thickness in radar absorption. This method has been applied by Chen et al [11][12][13][14] to make radar absorbing lattice panels. Both square lattice and triangular lattice were studied.…”

Design and reflectivity analysis of high temperature wave-absorbing coatings with circular periodic structure

“…However, the absorbing bandwidth of stealthy coating largely depends on the coating thickness. Besides, stealthy coatings bring undesirable extra weight and expensive maintenance costs for the aircrafts [3][4][5]. RAM are lightweight multifunctional structures not only for wave absorbing but also for load bearing.…”