DUAL BAND SWITCHABLE METAMATERIAL ELECTROMAGNETIC ABSORBER

This paper presents the design, fabrication and measure- ment of a dual band switchable metamaterial electromagnetic absorber. The unit cell of the metamaterial consists of dipole mode electric res- onators coupled by microwave diodes on one side of a dielectric sub- strate and metallic ground plane on the other side. Simulation and measurement results show that by forward or reverse biasing the diodes so as to change the coupling between the resonators, the absorber can be dynamically switched to operate in two adjacent frequency bands with nearly perfect peak absorption. Field distribution reveals the physical origin of the switchable performance based on the dipole mode of the electric resonator in the unit cell. It is also demonstrated that the frequency difierence between the two bands can be tuned by adjusting the loading positions of the diodes with unchanged high absorption, which helps to design absorbers with speciflc switchable working fre- quencies in practical applications.