M. Mahfoudi et Ji. Alonso, A SIMPLE TECHNIQUE FOR THE DESIGN OF MMIC 90-DEGREES PHASE-DIFFERENCENETWORKS, IEEE transactions on microwave theory and techniques, 44(10), 1996, pp. 1694-1702
In this paper, a simple technique for the design of broadband 90 degre
es phase-difference networks, using balanced and unbalanced all-pass n
etwork topologies, is presented, In the developed method, the element
values of the structures are calculated as function of two design vari
ables: Q(0) and r. Utilizing this approach, a 90 degrees phase shifter
has been realized, having less than 2 degrees phase error and better
than 0.5 dB amplitude error in the operating band from 0.7 to 3.5 GHz.