Analytical solution for the design of planar EBG structures with spurious-free frequency response

In this paper, an analytical solution is obtained for the design of Electromagnetic Bandgap (EBG) structures that feature a single stopband without the spurious rejected bands present in the conventional EBG devices at the harmonics of the design frequency. The design technique is applied to a two-port microstrip EBG circuit and to a four-port coupled-line EBG device in stripline technology obtaining very good results. The implementation of the EBG structure in coupled-lines allows for the redirection of the reflected signal to the coupled-port producing a device with input port matched at all frequencies.