custom microstrip resonator

Hi all,
I'm looking for a microstrip resonator (i.e. lambda/2) for circuit assembly.
Does anybody know where I can find something like that or someone that would
be able to build it?
The application require a resonant frequency of 2.5GHz and a Q factor of
200.

Thanks to all.

Alle.

 

You won't achieve a Q of 200 in microstrip. A tuned cavity would be
the solution here. Loose probe coupling into an air-spaced coaxial
chamber with a half wave inner will do it.

If you do decide to try microstrip, then you simply etch or scrape and
peel a piece of PC board to the appropriate length - nothing to buy.

d

_____________________________

http://www.pearce.uk.com

 

You might consider a coaxial ceramic resonator; they have Qs in the
thousands and are very stable.

John

 

You won't achieve a Q of 200 in microstrip. A tuned cavity would be

Thank you Don!
I need to place it into a PCB, and so I would ask you what are approximately
the dimensions of this cavity.

I need to do a Frequency-Voltage converter in the range of 2.5GHz and so my
application require two resonators with similar but not equal resonant
frequencies, with a difference of, say, 20MHz (something that look like old
FM demodulators).

In your opinion, is this slight difference achievable with resonant
cavities?

Thank you.

A.

 

First, to do this job you only need a single resonator. Look at the
way most FM tuner ICs work to see how to use it. The resonator need
only be a quarter wavelength. At 2.5GHz that is about 3cm in air. This
would be the case for a cavity. If you can get, as suggested, a
ceramic resonator, then it will be much smaller.

Alternative;y, you can downconvert the frequency so that the
percentage change is much greater.

d

_____________________________

http://www.pearce.uk.com

 

You can make your own resonators in a board by cutting a "notch" in the
ground plane (ask me - works like a charm, especially when you don't
want it - learn from your mistakes - I try to, but.....). VERY high Q
(> 200), really cool when you're not expecting it - I' buy off shelf
cavitys - tuning is better and they work when they are expected to.
Andrew

 

Andrew Paule wrote...

Talk us through a typical notch in the ground plane resonator.
Frequency vs size of notch, a more detailed description, etc.

Thanks,
- Win