Transmission waveguide resonator with dissipative and polarization-sensitive elements

The diffraction of Ep and Hp waves due to the inhomogeneous step expansion of a planar waveguide is analyzed. The resonant region consists of magnetodielectric layers, a resistive film, and a grating of parallel metal strips. The eigenmodes of the system are defined by the method of moments on the basis of equivalent boundary conditions and scattering characteristics. The solution is represented in the form of infinite systems of linear algebraic equations. The grating considerably increases the Q-factor of the trapped modes for Hp waves, decreases the velocity of such waves and affects differently the degree of intermode (Ep⇆En, Hp⇆Hn) transformation of the fields. A film with average conductance adds some dissipative losses but retains the dispersion dependences by selective action on the Q-factor of the trapped modes. The distinct boundary between attenuation and propagation regimes is absent. © 1999 Kluwer Academic/Plenum Publishers.