1. Single and Dual Mode Helix Loaded Cavity Filters
   S.J. Fiedziuszko, R.S. Kwok
   U.S. Patent # 6,031,436 (2000)
2. Voltage Tunable Patch Filter Element with Dielectrically Loaded Slot
   S.J. Fiedziuszko, R.S. Kwok
   U.S. Patent # 6,563,404 (2003)
3. No fastener Waveguide Structures
   R.S. Kwok
   U.S. Patent (pending)
4. Ceramic Filter with Higher Order Mode Cancellation
   R.S. Kwok
   U.S. Patent (pending)