alexdesigner
Newbie level 4
Hi! I recently designed a distributed VCO with hybrid (discrete components + transmission lines) following the guidelines in Skvor-Divina paper (reference[1,2] is provided below) in the range 1-2 GHz, that worked good enough, meeting the design requirements in terms of frequency of operation (apart from a 10% shift due to some inconsitency in the models for discrete devices) and output power.
Well, problems arose in designing a VCO in the band from 1.5 to 5 GHz using the same topology of [2], employing only transmission lines. From nonlinear simulation results, with HB in Agilent's ADS the circuit is capable of attaining oscillations, however, when measured it gives very different results and the oscillation frequenc. are totally deranged. Could it be an impedance matching problem? Did any of you have a previous experience with this kind of circuits and with its simulation?
Thanks!
Reference:
[1] Divina, L. - Škvor, Z.: Experimental verification of a distributed amplifier oscillator. In: Conference proceedings of the 25-th European Microwave Conference, pp. 1163-7, Nexus, Bologna 1995
[2]Divina, L. - Škvor, Z.: Distributed Oscillator at 4 GHz. In: IEEE MTT-S International Microwave Symposium Digest, part II, pp. 865-8, IEEE MTT-S, Baltimore, červen 1998 /Distributed Oscillator at 4 GHz. IEEE Transactions on Microwave Theory and Techniques 46(1998)12, pp. 2240-3.
Well, problems arose in designing a VCO in the band from 1.5 to 5 GHz using the same topology of [2], employing only transmission lines. From nonlinear simulation results, with HB in Agilent's ADS the circuit is capable of attaining oscillations, however, when measured it gives very different results and the oscillation frequenc. are totally deranged. Could it be an impedance matching problem? Did any of you have a previous experience with this kind of circuits and with its simulation?
Thanks!
Reference:
[1] Divina, L. - Škvor, Z.: Experimental verification of a distributed amplifier oscillator. In: Conference proceedings of the 25-th European Microwave Conference, pp. 1163-7, Nexus, Bologna 1995
[2]Divina, L. - Škvor, Z.: Distributed Oscillator at 4 GHz. In: IEEE MTT-S International Microwave Symposium Digest, part II, pp. 865-8, IEEE MTT-S, Baltimore, červen 1998 /Distributed Oscillator at 4 GHz. IEEE Transactions on Microwave Theory and Techniques 46(1998)12, pp. 2240-3.
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