An ultra broad band reflection type phase shifter MMIC with series and parallel LC circuits

摘要

An ultra broad band reflection type phase shifter is proposed. The proposed phase shifter has frequency independence characteristics in the case of 180° phase shift, theoretically. The phase shifter is composed of a 3-dB hybrid coupler and a pair of novel reflective terminating circuits. The reflective terminating circuit switches two states of series and parallel LC circuits. Using an ideal circuit model without parasitic circuit elements, we have derived the determining condition of frequency independence of circuit elements. Extending the concept, we can also obtain a broad band phase shifter for other phase difference as well. In this case, for a given phase difference and an operating frequency, we also derive a condition to obtain minimum variation of phase difference around the operating frequency. The fabricated MMICs have successfully performed good characteristics over a broad band width.