Tw. Yoo et al., 360-DEGREES REFLECTION-TYPE ANALOG PHASE-SHIFTER IMPLEMENTED WITH A SINGLE 90-DEGREES BRANCH-LINE COUPLER, Electronics Letters, 33(3), 1997, pp. 224-226
A small reflection-type 360 degrees analogue phase shifter is realised
with four varactors and a 90 degrees branch-line coupler. New design
formulas for the phase shift and the insertion loss are derived and ap
plied to the circuit optimisation. The phase shifter shows a total pha
se shift of 380 degrees and an insertion loss of 4.5+/-0.8dB at 10GHz.
The variation of the phase is <4 degrees over the whole range of temp
erature from 0 to 50 degrees C.