Bandwidth Enhancement in Dielectric-Lined Circular Waveguides (Short Papers)

The increase in TE₁₁-TM₀₁ mode bandwidth obtained by inhomogeneously loading (dielectric lining) a circular waveguide is systematically documented. Maximum bandwidth is about 31.83 percent of center frequency (up from about 26.54 percent for fully filled or empty circular waveguides). This makes circular waveguides competitive with square waveguides (bandwidth≈ 34.3 percent) as radiators in wide-band dual-polarization arrays. Certain interesting symmetries involving the TE₂₁-TM₀₁ modal inversion are also examined.