Dual band planar soft surfaces

The design of dual band planar soft surfaces is presented here. Based on previous works, the parameters of a particular planar realisation of soft surfaces are used to create two frequency bands in which surface waves are suppressed. The planar soft surface is made with strips printed over a grounded dielectric slab with grounded vias. The parameters of the soft surface such as the strip width, the period of the vias and the position of such vias across the strip determine the frequency band at which the structure has a bandgap. It is demonstrated that by interleaving two planar soft surfaces with some different parameters over each other, the stopband of each one of them is maintained, and consequently, a dual band operation is obtained. Any of the mentioned parameters can be employed to this aim as shown in this work. The conclusions are supported by experimental results. The agreement between the measurements and the simulation results is good enough to demonstrate the dual band effect.