180$^{\circ}$ and 90$^{\circ}$ Phase Shifting Networks With an Octave Bandwidth and Small Phase Errors

A new phase shifting network for both 180deg and 90deg phase shift with small phase errors over an octave bandwidth is presented. The theoretical bandwidth is 67% for the 180deg phase bit and 86% for the 90deg phase bit when phase errors are plusmn2deg. The proposed topology consists of a bandpass filter (BPF) branch, consisting of a LC resonator and two shunt quarter-wavelength transmission lines (TLs), and a reference TL. A theoretical analysis is provided and scalable parameters are listed for both phase bits. To test the theory, phase shifting networks from 1 GHz to 3 GHz were designed. The measured phase errors of the 180deg and the 90deg phase bit are plusmn3.5deg and plusmn2.5deg over a bandwidth of 73% and 102% while the return losses are better than 18 dB and 12 dB, respectively.