Hi guys
actually I have designed and built a 50MHz low pass filter and someone tested it with a VNA but I'm wondered why the VSWR in the low frequency is not good!
red line is the response:
Insertion Loss is very good and very similar to the software simulation:
now VSWR:
as you see the VSWR at the low frequency is not very good (red line). it should be like the blue line based on the software simulation.
what do you think about the filter?
I have used CS series from Coilcraft inductors (0603) and TDK COG type capacitors (0402)
my friend connected two 1 meter cable at the both connector of the filter. he told me I calibrated the setup.
Thanks