环形波导

例句：

1. 1. The annular waveguide is used in the transmission of high-frequency signals.
   环形波导用于传输高频信号。
2. 2. The annular waveguide is a critical component in the design of radio and microwave devices.
   环形波导是设计无线电和微波设备的关键组件。
3. 3. Annular waveguides are commonly used in telecommunications systems to improve signal quality.
   在电信系统中，环形波导常被使用来提高信号质量。