Hi Peter and Jim,

Thanks for the replies. This is a microstrip hairpin filter (uses coupled
resonators made from quarter wave sections of microstrip transmission
line), so I can't simply set up a SPICE simulation. Also, I think that
these DO have typically greater insertion loss than discrete element
filters (of the same order) do, but I'm not certain. Also, this filter has
three sections, I'm not sure if this equates to a regular 3-pole filter or
not. I suspect not, because  I think that each section contributes more
than one pole.

I have Sonnet lite, a program for analyzing these types of circuits but I
don't know how to convert from dissipation factor (the spec in the PCB
laminate datasheet) to dielectric loss tangent (the spec that Sonnet wants).

In addition, it is entirely possible that my design was too restrictive in
some way, so I'd like to get an idea for what a typical hairpin filter IL
is, so that, even if I am getting the best for my design, I can see how
much I stand to gain by relaxing the design.

Sean


At 06:25 PM 3/27/02 +0200, you wrote:
> >Hi Peter,
> >
> >Thanks for the quick reply. Is the insertion loss typically 10dB for only
> >a three element filter? If so, why do I see boards with 5 and 6 sections
> >in them! Wouldn't the loss be prohibitive?
>
>Imho set up a Spice simulation and see what happens ...
>
>At least at HF/IF frequencies I know of 2-3dB loss in a 3 stage Chebyshev
>with not so good coils and silver mica caps.
>
>Peter
>
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