We present the design of two continuous tunable CW coaxial cavity gyrotron oscillators, one of 330 GHz - 200 W with a bandwidth of 3 GHz for scientific applications and one of 30 GHz-150 kW with a bandwidth 0.4 GHz for industrial applications. The tuning of both gyrotrons is achieved by moving the tapered inner conductor in the axial direction and by adjusting the operating magnetic field.

The scattering properties for both TE and TM modes of an abruptly ended two-layered slab waveguide with anisotropic core and isolated substrate are examined by an improved iteration technique, which is based on the integral equation method with accelerating parameters. The relative dielectric constants of the core for the three Cartesian directions are considered to be different, but cases with isotropic core are also considered. The electric field distribution on the terminal plane and the reflection coefficients of the dominant TE and TM guided modes, as well as the near-field distribution and the far-field radiation pattern, are computed, while numerical results are presented for several cases of the core anisotropy.