mw_rookie
Member level 2
ads+lna+feedback
I am designing an LNA at 2 GHz and the S-parameters are:
S11 = 0.972 ang(-21)
S21 = 4.436 ang(153.9)
S12= 0.026 ang(73.8)
S22 = 0.612 ang(-16.6)
and K<1 so I calculated Γs and ΓL and also got the input and out stability circles using smith chart utility in ADS. But, both Γs and ΓL are almost on the circle and its difficult to judge whether they lie in the stable or unstable region. the question is since K<1 shouldnt there be a value of Γs that lies in the stable region and one in the unstable region rather than both in the same region and likewise for ΓL and the worst part is the magnitude of the relection co-eff.s are about 1 in magnitude using these S-parameters though the angles vary...can anybody help??? thanx
I am designing an LNA at 2 GHz and the S-parameters are:
S11 = 0.972 ang(-21)
S21 = 4.436 ang(153.9)
S12= 0.026 ang(73.8)
S22 = 0.612 ang(-16.6)
and K<1 so I calculated Γs and ΓL and also got the input and out stability circles using smith chart utility in ADS. But, both Γs and ΓL are almost on the circle and its difficult to judge whether they lie in the stable or unstable region. the question is since K<1 shouldnt there be a value of Γs that lies in the stable region and one in the unstable region rather than both in the same region and likewise for ΓL and the worst part is the magnitude of the relection co-eff.s are about 1 in magnitude using these S-parameters though the angles vary...can anybody help??? thanx