Design of Miniaturized Wideband Microwave Absorber Loaded with Lumped Resistance

Abstract

In this paper, a polarization and angular insensitive microwave absorber with miniaturized structure is proposed. This structure integrates lumped resistances into a metallic bow-tie structure, thus achieving wideband absorbing performance. It can be found that the metallic bow-tie structure increases the equivalent capacitance and equivalent inductance, which enables the absorber with an electrically small structure. The presence of substrate and air layer contributes a lot to the broadband absorption in relative low frequency band. The size of the unit is about 0.092λ_L, and the total thickness is only 0.080λ_L in correspondence to the lowest frequency. Simulated results show that the absorptivity exhibits good stability with respect to different polarized incidence and different incident angles. The absorber exhibits wideband absorptivity above 90% from 2.3 GHz to 9.6 GHz with a relative absorption bandwidth of about 123%. The measured results are in good agreement with the simulated one, which demonstrates the absorber capable of good potentiality in electromagnetic (EM) stealth applications.