Dual-band thin printed microwave absorber

Abstract

A dual-band thin printed-circuit-board (PCB) microwave absorber is proposed for applications in 2.4 and 5 GHz frequency bands. Each unit cell of the absorber utilized a simple combination of a square ring and a thick cross-dipole with some additional tuning elements. In the design process, numerical simulations were performed first for optimal characteristics, and then a prototype absorber was created successfully by simple print-transferring and etching processes. The measured absorption bandwidth (50%) of 170 MHz (2.36-2.53 GHz) and 830 MHz (5.09-5.92 GHz) are achieved for the first and second band, respectively, with the wideband feature at the second operating band. The absorption at the center frequencies of bands, 2.45 and 5.5 GHz, are also found feasible at 97.85% and 97.76%, respectively. From the experiments, the proposed absorber was suitable for many applications requiring absorptions in the 2.4/5GHz bands as desired. The measured results were agreed well with ones from the simulations. The advantages of the proposed absorber are thin, simple and low-cost structure that can be useful for cost-effective applications.