Microwave absorber based on encapsulated expanded graphite-silicone composite as meta-“atom” for X-band application

Abstract

In this work, a wideband microwave resonating-type absorber is investigated in terms of metal backed metamaterial absorber (MMA). Expanded graphite-silicone (EG-Si) composite is encapsulated in the flexible silicone rubber matrix to build periodic unit cell of the MMA. Microwave material characterization of the EG-Si composites with different weight percentages (1, 3, 5, 7, 9 and 11 wt. %) is carried out at X-band frequency range. CST simulation is performed to optimize the unit cell parameters i.e. a wideband absorption with at least −10 dB absorption bandwidth (BW) throughout the X-band is obtained. Simulation is also carried out to check the polarization and incident angle dependency of the absorber’s absorption performance. The resonance and absorption mechanism of the absorber are investigated with the help of simulated electric field, magnetic field and current density inside the unit cell. The absorption of the prototype absorbers is experimentally measured by waveguide measurement technique.

KEYWORDS:

• Microwave absorber
• metamaterial absorber (MMA)
• wideband absorber
• unit cell
• periodic structure and X-band

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Dhruba Jyoti Gogoi

Dhruba Jyoti Gogoi, I have received the Master’s degree in Physics (in the year 2014) with electronics and photonics specialization from Tezpur University, Assam, India. I have received the PhD degree from the same University (in December, 2019) for the thesis entitle, “Development of low profile X-band microwave absorber using embedded meta-structure in flexible matrix”. I have been selected as an Assistant professor in the Nalbari College under affiliation of Guwahati University, a state university of Assam, India (But due to COVID-19 pandemic, I am still not able to join in the college). My research interests are Computational Electromagnetics, Antennas for Wireless Communication and EMI/EMC.