Experimental Verification of Evanescent-Wave Amplification and Transmission Using Metamaterial Structures

Summary form only as given. We study the evanescent-wave amplification (EWA) and evanescent-wave transmission (EWT) using two metamaterial structures. In the first experiment, we propose a structure of planar waveguide inserted by a left-handed material (LHM). As we know, the evanescent waves (or cutoff waves) can be easily generated in a planar substrate integrated waveguide (SIW), which behaves quite similar to the conventional rectangular waveguide. We insert a structured LHM that is composed of distributed series capacitors and shunt inductors into SIW to verify the EWA and EWT phenomena. From both simulation and experimental results on transmission coefficients, we observe that evanescent waves are amplified and transmitted through the structured LHM metamaterial within the frequency band that exhibits the negative refraction. We also show that the evanescent waves cannot be transmitted if we insert a right-handed microstrip line or distributed capacitor circuits inside SIW. Such experiments directly confirm the EWA and EWT phenomena through LHM metamaterial.