A simulation problem about DIELECTRIC RESONATOR OSCILLATOR.

[Zoarbary]

dielectric resonator oscillator

Most RF transistors need input matching and output matching(conjugate matching) to achieve maximal gain. However, the PARALLEL FEEDBACK DIELECTRIC RESONATOR OSCILLATORS(DRO) do not need the matching.

Here comes the problem: if there is no matching, the loop gain of the PARALLEL FEEDBACK DRO in Agilent ADS is too small to start oscillating, but experiments show the PARALLEL FEEDBACK DRO are ABLE to oscillate.

So I am wondering how to deal with the transistor with no matching in ADS.

See the attachment, it is a technical report from SIMENS. The PARALLEL FEEDBACK DRO in it has no matching network, but is able to oscillate. However, the simulation results in it are not done by ADS, but a software rarely seen.

Thanks for your reply.

 

[Zoarbary]

resonator oscillator

who knows?
thanks for your help!

 

[FvM]

dielectric resonator dro application note

However, the simulation results in it are not done by ADS, but a software rarely seen.

There has been RF engineering before ADS.

Generally, adding a stimulation reveals if an oscillator is able to work - in any simulation software.

 

[Zoarbary]

dielectric resonator

However, the simulation results in it are not done by ADS, but a software rarely seen.

There has been RF engineering before ADS.

Generally, adding a stimulation reveals if an oscillator is able to work - in any simulation software.

I know what you mean, but I am required to include some simulation results in my report. And the principle of the oscillator is self-oscillation induced by parallel positive feeback, so stimulation may not be available in my report. The experiment of the oscillator has been done.

 

[FvM]

dielectric resonator oscillator design

It's known, that oscillators may not start in simulation due to simulator problems. A stimulation can overcome this problem and be switched off after bringing some initial energy to the oscillator. Furthemore, it reveals insufficient positive feedback, missing in the real circuit or the model only.

 

[biff44]

dielectric resonator oscillator circuit design

The paper clearly states, as it should, that "open-loop small signal gain must exceed unity". Are you sure that your small signal gain is not greater than unity? How are you modelling the feedback path loss?

 

[Abhishekabs]

principle of dielectric resonator oscillators

Hi Zoarbary
See the Images attached.
In first attachment, you will see a microstrip resonator in feedback insted of DRO.
But the technique looks same.
I think The oscillator shown in the application note is is not designed by negative resistance oscillator design technique.
See second attachment.
You need to adjust phase shift.
You dont need matching circuit for oscillator.
You need to place buffer at the output to avoid frequency shift due to load variation

Check the datasheet of SIEGET BFP405 & see what is open loop gain.(check S21)

ABhishekabs

 

[Abhishekabs]

simulation resonator software

Fig 2.

 

[Abhishekabs]

Also regarding your simulation query.
This is Similar to HB simulation done in ADS for Oscillator
So you can show in your report the simulation of circuit shown in fig 1 & can say insted of this resonator DRO is placed & effect is studied.
I just want to help you out in your report problem

 

[accutemicro]

Re: A simulation problem about DIELECTRIC RESONATOR OSCILLAT

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