Bandwidth‐reconfigurable filtering phase shifters with phase‐slope alignment for different bandwidth states

Abstract

AbstractIn this article, filtering phase shifters with the capability to reconfigure their operating bandwidth are proposed for the first time. The proposed phase shifter is based on a triple‐mode half‐wavelength microstrip‐line resonator with two loaded stubs. The operating bandwidth of proposed phase shifters can be adjusted by changing the frequency ratio (Rf) between the third (fp3) and the first (fp1) resonant frequencies, which can be flexibly controlled by changing the length of loaded stubs. Meanwhile, phase slopes also can be aligned by further studying Rf to achieve low phase errors. For validation, 90° phase filtering phase shifters centered at 2.5 GHz are designed, and measured. Measured results indicate that the fractional bandwidth of this phase shifter can be flexibly tuned from 16% to 36% with good filtering performance. Meanwhile, the phase error and magnitude imbalance of the proposed 90° phase shifters are less than ±5° and 0.3 dB, respectively.