Microwave oscillator design

[faisal]

microwave oscillator design

Hi,
I want to design a microwave oscillator of abour 550MHz.
the requirements are that it should be very stable. I want to ask
whether a crystal oscillator will serve fine for this purose or tunnel or impatt
diode based oscillator will also do.
also tell me the advantages and disadvantages of both the crystal and impatt or cystal based oscillators.
Also this oscillator will be used as a reference oscillator in a pLL frequency synthesizer.
regards,
FAISAL

 

[djalli]

Impatt handles more power that is for sure one advantage and will do fine as pll compared to crystal oscillator.

Explain a little bit more what you said "should be very stable". Is this stability factor you are talking?

 

[faisal]

Impatt handles more power that is for sure one advantage and will do fine as pll compared to crystal oscillator.

Explain a little bit more what you said "should be very stable". Is this stability factor you are talking?

should be very stable means that
it should oscillate at exactly the right frequency for it is designed.
What about tunnel diode oscillators.
thanks

 

[mr_ghz]

Hi faisal

If you need a stable oscillator I would choose a crystal. If you need a frequency of 550MHz you can use a 50MHz crystal and multiply it by 11. A good output filter will remove all unwanted (sub-)harmonics.
The advantage of a crystal is a very low phase noise compared to tunnel or impat diode. Also the frequency is very low for such diodes. (550MHz is nearly DC...)

Best regards
mr_ghz

 

[biff44]

Impatts, Tunnel diodes? Maybe a backward wave oscillator would really complete the list. How aboout a para amp using a pumped varactor diode. On the other hand, this is 2005....LOL.