本文指出:扇形波导内存在的波型是园形波导内的部分波型,但这些波型无简并;其次低型波之截止波长距基波较园形波导远;同时指出了扇形波导(特别是π/5扇形波导)是可能传输毫米波的金属波导管。从而显示了扇形波导在传输电磁波时较园形波导优越。 This paper points out that the wave modes present in the sector waveguides are part of the waveguides in the circular waveguide, but none of these waveforms are degenerate. The cutoff wavelength of the low-wave is far from that of the circular waveguides. At the same time, Especially π / 5 sector waveguides) are metal waveguides that can transmit millimeter waves. It shows that the fan-shaped waveguide is superior to the circular waveguide when transmitting electromagnetic waves.