High-Q open resonance structures with rare spectra

A method is proposed whereby high-Q coaxial open resonance structures with rare spactra can be implemented using magnetic oscillations with a radial index other than unity. The operating principle of such open resonance structures is based on locking a waveguide wave between two critical sections. The class of open resonance structures proposed here can be useful in short millimeter bands and at higher frequencies. These structures can be applied to the traditional laser systems, free-electron lasers, gyrotrons, and measuring instruments.