A new waveguide stepped septum-type circular polarizer (SST-CP) was developed to operate in the 500-GHz band for radio astronomical and planetary atmospheric observations. In a previous study, we developed a practical SST-CP for the 230-GHz band. However, several issues prevent this device being easily scaled down to the 500-GHz band, such as manufacturing dimensional errors and waveguide flange position errors. In this study, we developed a new waveguide flange with a high-accuracy position determination mechanism and a very small size of 10 × 10 mm. We also developed a new fabrication technique to obtain very good flatness for the device’s blank materials by high-accuracy polishing using a resin fixture. Using these new methods, the manufactured 500-GHz band SST-CP achieved a cross-polarization talk level of better than – 30 dB at 465–505 GHz, a device surface flatness of within 3 μm, and also the horizontal positioning error of ± 3 μm. These results indicate that the developed 500-GHz band SST-CP has high performance in the high-frequency band, and thus the new manufacturing methods are effective in the 500-GHz band.

开发了一种新的波导阶梯式隔片型圆偏振器（SST-CP），可以在500 GHz频段内进行射电天文和行星大气观测。在先前的研究中，我们为230 GHz频段开发了实用的SST-CP。但是，由于一些问题，例如制造尺寸误差和波导法兰位置误差，导致该设备无法轻松缩小至500 GHz频段。在这项研究中，我们开发了一种新型的波导法兰，该法兰具有高精度的位置确定机制，并且尺寸很小，仅为10×10 mm。我们还开发了一种新的制造技术，可通过使用树脂夹具进行高精度抛光来为设备的毛坯材料获得非常好的平整度。使用这些新方法，制造的500 GHz频段SST-CP在465–505 GHz时达到了优于– 30 dB的交叉极化通话水平，器件表面平整度在3μm以内，水平定位误差为±3μm。这些结果表明，开发的500GHz频带SST-CP在高频频带中具有高性能，因此新的制造方法在500GHz频带中是有效的。