Harmonic balance simulation issues with feedback oscillator

i have simulated the feedback oscillator found in this tutorial using ADS and it worked well
http://www.odyseus.nildram.co.uk/RFM...Oscillator.pdf
when i changed the values of the resonator to resonate at another frequency the open-loop analysis was good but for the closed-loop analysis the harmonic balance simulation has no output, what could be wrong? note that K, S(2,1), Maxgain has good values

regards

Have you checked that you have more reflection gain than the resonator loss? and secondly have you checked the phase is zero? Or that the phase looking into the resonator is opposite sign (but same value) to that looking into the reflection oscillator?

the problem is that S11 of the resonator is -35db and the amplifier gain is 10db, is there another way than increasing the amplifier gain to have oscillation? the resonator losses is too high,maybe i should change the coil to have higher Q, will this solve the problem?

Dear Redhat

i have simulated the file u sent , and it give a good results

see the attachment
also to know when the oscillator will fail , try to tune the valuse of the resonator

wish this help

khouly