Author(s): Zhang, JQ (Zhang, Jiaqi); Wu, XY (Wu, Xiaoyu); Liu, LY (Liu, Liyuan); Huang, C (Huang, Cheng); Chen, XY (Chen, Xieyu); Tian, Z (Tian, Zhen); Ouyang, CM (Ouyang, Chunmei); Gu, JQ (Gu, Jianqiang); Zhang, XQ (Zhang, Xueqian); He, MX (He, Mingxia); Han, JG (Han, Jiaguang); Luo, XG (Luo, Xiangang); Zhang, WL (Zhang, Weili) 

Source: OPTICS EXPRESS  Volume: 27  Issue: 18  Pages: 25595-25602  DOI: 10.1364/OE.27.025595  Published: SEP 2 2019   

Abstract: The absorption region of a water-based absorber was expanded by introducing tetramethylurea (TMU) into the inclusion, whose dielectric properties are tunable through the concentration of TMU. The dielectric spectroscopy of a TMU/water mixture was deconstructed using a Debye model. We designed a four-layer ultra-broadband microwave absorber with a supernatant micro-structure. Simulation and experiment results indicate that the absorber can achieve 90% perfect absorption, covering a broad frequency range of 4-40 GHz. The concentration dependence of the absorber was also studied experimentally and numerically. The concentration control provides a more practical and large frequency-region modulation of perfect absorption. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement 

ISSN: 1094-4087