新型4-bit和5-bit宽带砷化镓单片数字移相器

Investigation of Novel Broad Band 4-bit and 5-bit GaAs MMIC Digital Phase Shifters

在GaAs基片上实现的多级级联3dB耦合线开关反射式宽带单片数字移相器在相移精度、输入回损等关键性能上良好,但通常面积很大,而多级级联的高低通网络移相器面积较小而宽带性能较差。通过多节GaAspHEMT开关的组合改变3dB耦合线的直通端和耦合端的反射体的电长度,在6～18GHz的频率范围内实现不同的相移量。该结构只采用两级3dB耦合线结构级联,减小了芯片面积,减小了多节耦合线级联引入的寄生损耗。测试结果验证了结构的合理性:性能上与传统结构相当,但芯片面积缩小为50%～60%。

The multi-bit cascaded broadband monolithic 3-dB hybrid reflection-type phase shifters fabricated on GaAs may exhibit excellent performances such as low absolute phase error and return loss,but it always occupy large die area and introduce high parasitical insertion loss;the high-pass/low-pass phase shifter demonstrates smaller die area,but with worse performance.Applying several GaAs pHEMT switches combination to change the electrical lengths of the phase controllable LC terminators which are connected to the coupled and direct ports,one coupler can achieve different phase shift over 6～18GHz.Two phase shifters only use two couplers,but the shifes cover full range of 0°～360°.The insertion loss and chip area are reduced.The measured results show they have similar performance to traditional topology and the total die area is reduced to 50%～60%.