Broadband Low-Profile Frequency Selective Rasorber Using Ultraminiaturized Metal-Graphene Structure

• Published in: IEEE antennas and wireless propagation letters 2022-12, Vol.21 (12), p.2422-2426
• Main Authors: Wu, Bian, Zhang, Ding, Chen, Biao, Yang, Yao-Jia, Zhao, Yu-Tong, Su, Tao
• Format: Article
• Language: English
• Subjects: Absorption; Broadband; Broadband communication; Equivalent circuits; Frequency ranges; frequency selective rasorber (FSR); Graphene; Impedance; Inductance; Insertion loss; low-profile; metal-graphene; Metals; Scattering parameters; Screen printing; ultraminiaturized
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2022.3195811

In this letter, a broadband and low-profile frequency selective rasorber with an ultraminiaturized metal-graphene structure is proposed. The rasorber is composed of two cascaded layers separated by an air spacer, a top lossy layer and a bottom bandpass layer. By supplying four branches of multiple vias connected stubs across a circular graphene film in the lossy layer, extra inductance and capacitance effects are introduced while guaranteeing the impedance match with the free space at the low frequency range. As a result, a broad absorption bandwidth is ensured from 1.96 to 10.2 GHz with the thickness of only 0.076 λ l at the lowest absorption frequency, and the passband is at 12.83 GHz with the insertion loss of 0.23 dB. Besides, a miniaturized unit is achieved with the period of 0.039 λ l , and the oblique angle incidence response is up to 45° for TE and TM modes. To validate the design, a prototype is fabricated and measured, and the screen-printing process of graphene resistive film as omnidirectional resistance is adopted to further reduce the profile. The measured results agree well with the simulation.