一、引言随着工作波长进入到毫米波波段,波导元件的尺寸都要相应地缩小.由于波导管的截面尺寸决定了管内的波导波长和特性阻抗,因此,对波导管的加工提出了一定的公差要求.在精密测试设备中使用的波导管的公差要求达到二千分之一自由空间波长的数量级,有时甚至还要更高些.对毫米波波段的波导来说,其公差要求小于5微米. I. INTRODUCTION As the working wavelength enters into the millimeter wave band, the size of the waveguide element should be reduced accordingly.As the waveguide cross-sectional dimension determines the waveguide wavelength and characteristic impedance in the tube, a certain Tolerances Requirements Waveguides used in precision test equipment require tolerances in the order of one-twelfth of a second of the free-space wavelength, and sometimes even higher. For millimeter waveband waveguides, their tolerances are required to be less than 5 microns .