12-18GHz宽带铁氧体移相器设计

Design of Wide-Band Ferrite Phase Shifter For 12-18GHz

采用矩波导结构形式,对影响饱和差相移的主要参数进行优化,设计了一个可工作于12-18GHz,带宽40%的双环铁氧体移相器,饱和差相移370°,频散约7.8°,插入损耗优于-0.4dB。整个带宽内最少存在三个高次模,但都未被激发。用两级转换器对宽度为15.8mm的空波导进行匹配,可实现反射损耗小于-20dB。计算结果还显示,通过调整两级匹配介质的介电常数和增加一个容性台阶,可以改善移相器的宽带匹配性能。按设计制作出的移相器实测性能:饱和差相移约360°,频散约8°,整个带宽内无损耗峰出现。在12-17.5GHz内插入损耗优于0.6dB,驻波小于1.4。

Using rectangular waveguide structure, and optimizing main parameters which affect the saturated differen-tial phase-shift, a twin-toroidal ferrite phase shifter which can work from 12 to 18GHz is simulated. The bandwidth is up to 40%. The frequency dispersion is about 7.8°while the amount of saturated differential phase-shift is about 370°. The inser-tion loss is better than 0.4dB. At least three high-order modes exist, however they are not excited in the band. Matching the phase shifter to the waveguide whose width is 15.8mm by two-step transformers. The return loss is less than -20dB. Simula-tion shows that wide-band characters may be improved by adjusting the permittivity of the transformer dielectrics and adding a capacitive step. A sample phase shifter is manufactured according to the design. Results of test indicate that the saturated differential phase-shift is about 360°, the frequency dispersion is about 8°and no peaks of insertion loss appear in the band. The insertion loss is better than 0.6dB and the VSWR is less than 1.4 in 12-17.5GHz.