Microwave filters with simultaneous conditions on amplitude and phase

The author reviews and examines a number of the more important methods of achieving simultaneous specifications on the amplitude and delay responses of microwave filters. No attempt is made to cover all of the approaches taken to this problem, but rather some of the more basic techniques are chosen to illustrate the nature of the problem and the general constraints which apply. The necessity of taking into account the eventual circuit realization is highlighted. Two classes of problems are distinguished. In one class, a simple realization in the form of cascaded transmission lines is used, resulting in restrictions on what may be achieved. Alternatively, by using non-minimum-phase structures it is shown how independent and optimum results in terms of both characteristics may be found