Sub-THz notch filters based on photonic bandgaps in overmoded waveguides

Photonic Bandgaps (Bragg reflectors) in moderately oversized corrugated waveguides can be applied as notch filters in the mm and sub-mm wavelength range. They offer unique options such as very steep frequency slopes, narrow or wide stop bands and very low insertion loss when compared to other technologies such as coupled cavity or Fabry-Pérot type filters. Also several defined stop bands within one frequency band are feasible.