Compact Tri-Band Microstrip Stub Filter Using Embedded MTM-EBGs

This work introduces a methodology for designing multi-band devices using the recently introduced metamaterial-based EBG (MTM-EBG). Cascaded MTM-EBG sections are used to realize a tri-band quarter-wavelength microstrip stub with arbitrarily chosen operating frequencies, which is then employed as a compact tri-band-stop filter. Simulated and measured results are in very good agreement, and demonstrate rejection of over 20 dB at all band-stop frequencies. Enhanced functionality could be achieved in many other microstrip devices with this approach.