harmonic balance simulation in ADS

hi all..
jus wanna know...what does harmonic balance simulation shows...like say i performed harmonic balance simulation 1-tone on an amplifier at some frequency say 10GHz (input power 10dbm)...what i got was about 7db at 10GHz and -ve db values at the other 5 harmonics...how can i interpret it..

the Hramonic balance show the circuit ouput due to single tone or multi tone exitation , so u can analyze amps , mixers power amps and so on

when u inject a 10 GHz to amp , the nonlinearities in the amp will generate the harmonics as well , so u can measure these ,

also u can sweep the input power so u can dtermine the 1 dB comp point
khouly

hi khouly..

first of all...thanks for replying..

i wanna ask...what is 1 db compression point and how do i determine that...(this may sound a silly basic question to u ..but am very new to this field..so..)

and one more thing...if i am getting some -ve db values at other harmonics (please refer to my original question)..so does this means that the ckt is not going into non-linearity...

the 1 dB coompression point is the point the gain well fall be 1 dB from the linear valuse , this is happend due to saturation of the amplifier

the -ve this mean that the power in these harmonics , but as these harmonics are generated the circuit is nonlinear
but as these harmonics become less , this means the linear behaviour of the circuit is good

khouly

hi khouly..

thanks for the response..

lets suppose...i have a FET model to be used to design an amplifier in ADS...so can i see the 1 db compression point using some kind of plot in ADS..

yeah , in harmoic balance , make the input power to be swept , and plot the output power of the first harmonic so , the graph should show u the 1 dB compression point

khouly

thanks khouly..

that was quite helpful to me...

check this out

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