# ECE145a_218a_F11_HW3_Solns - UCSB ECE218/145A 2011...

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UCSB ECE218/145A 2011 Homework 3 Solution by Qikun XUE [email protected]
Problem 5 ADS for problem 2 :Circuit Simulation results : S-parameter From the plots above we can see that at low frequency, S21 has been successfully set to 10dB and has 3dB bandwidth at 81.5GHz which is very close to our hand analysis result 82.2GHz. R R6 R=Rx VAR VAR1 ft=300e9 Cgs=gm/(2*pi*ft) F Cgd=0.001fF RL=67 gm=0.1264 Rds=25/gm Ri=0.5/gm Rx=50 Eqn Var S_Param SP1 Step=0.1 GHz Stop=300 GHz Start=0.1 GHz S-PARAMETERS R R7 R=RL Term Term2 Z=50 Ohm Num=2 Term Term1 Z=50 Ohm Num=1 VCCS SRC1 G=gm S C C1 C=Cgs R R2 R=Rds R R5 R=Ri m1 freq= dB(S(2,1))=9.998 100.0MHz m2 freq= dB(S(1,1))=-39.549 1.000GHz m3 freq= dB(S(2,1))=7.012 81.50GHz 1E9 1E10 1E11 1E8 3E11 -60 -40 -20 0 -80 20 freq, Hz dB(S(1,1)) m2 dB(S(1,2)) dB(S(2,1)) m1 m3 dB(S(2,2))
Simulation results : MAG From the plot above we can see that ,f MAX is about 1061GHz, and MAG at 50GHz is 26.53dB. These are excellent match with the values calculated from our hand analysis Note: a C GD of 0.001fF was added to the circuit for this simulation step because it is not possible to