eSeptum - Waveguide Bandpass Filters - Version 3.2 eSeptum is a waveguide filter design program. The software is fully functional except the waveguide band is locked to WR19 (useful for 40 to 60 GHz Filters). Upgraded software will design waveguide bandpass filters in any waveguide band. User friendly and intuitive. Extremely useful for RF Engineers and students.