Corrections to 'An ultra-broad-band reflection-type phase-shifter MMIC with series and parallel LC circuits'

摘要

The above-named article [ibid., vol. 49, no. 12, pp. 2446??2452, Dec. 2001] analyzed an ultra-broad-band reflection-type phase shifter. This phase shifter consists of a 3-dB hybrid coupler and a pair of reflective terminating circuits that switch two states of ideal parallel and series circuits. The authors have extracted the circuit elements of parallel and series as functions of center frequency and desired phase difference to obtain broadband characteristics. Two reflecting terminating circuit monolithic microwave integrated circuits (MMICs) with 90 and 180 phase shifts were designed and fabricated at the conclusion of the article. We respectfully express what seems to be error. For circuit topology shown in Fig. 2, the authors extracted circuit element values (eqs. (30)-(33)) to achieve broadband characteristics. These formulas are the most important part of the article, but they are incorrect. The correct inductive and capacitance circuit elements and given here.