Scott wrote:
I want to build a low pass filter for 1296 and have scaled a design out
of the handbook. I would like to use chip inductors and chip capacitors
for the filter. I was looking at thin film chip inductors (Digi-Key)
and they list the self resonant frequency. For an inductor passing
1296, what should the minimum self resonant frequency be? Is 10 GHz
enough? The filter is a 5 element Chebyshev Low Pass Filter, inductive
input (3 coils in series with a cap at each inner junction to ground),
Fco=1290 MHz, F-20dB=2600 MHz. Any other component specs I need to be
aware of?

Scott
N0EDV

Inductance of the capacitors, capacitance of the inductors, and loss of
both will all affect the quality of the filter. Parasitic inductances
and capacitances in the connecting lines and mounting pads will play a
role also. Your problem probably won't be so much getting decent
response to 2600 MHz (although it won't be easy), but maintaining good
attenuation for some range above that. Take a careful look at the
highest frequency you have to reject and the required attenuation at
that frequency, then decide whether your components will behave as
expected up there.

Roy Lewallen, W7EL