xbtxbt
Member level 2
cascade saw filter -80db
Today,I connected two filters by coaxial lines of 50 ohm in series to get a better performance of the filters.But on the net analyser's screen,I saw several unexpected peaks of S12 beside the center frequency.I simulated this case by Ansoft Designer,I found the transmission strip have a great effect on the performance of the cannected filters.I have no idea about this.The impedance of filter is 50 ohm as the same with transmission strip.Why they an't be connected is series?I think it must be the phase influence the S12 on some frequency,So on these frequency points,We will find peaks.But I don't have any theory to support the idea.Our filters are tunable filters with the range of 800MHz to 1.4GHz.Would you like to give me some suggestions?TKS!
Today,I connected two filters by coaxial lines of 50 ohm in series to get a better performance of the filters.But on the net analyser's screen,I saw several unexpected peaks of S12 beside the center frequency.I simulated this case by Ansoft Designer,I found the transmission strip have a great effect on the performance of the cannected filters.I have no idea about this.The impedance of filter is 50 ohm as the same with transmission strip.Why they an't be connected is series?I think it must be the phase influence the S12 on some frequency,So on these frequency points,We will find peaks.But I don't have any theory to support the idea.Our filters are tunable filters with the range of 800MHz to 1.4GHz.Would you like to give me some suggestions?TKS!