DimaA
Member level 3
I've designed a microstrip bandpass filter in range 3.2-3.9 GHz using ADS. The substrate is FR4 (Er=4.7,tand=0.01,h=1.6mm). The simulation run ok and everythinng seemed to be ok. But when I built the filter and started to measure I discovered few strange things.
First, the whole filter response was shifted about 300MHz right: center frequency is now 3.8 GHz instead of 3.5GHz, and the bandwith was about 300MHz instead of 700MHz.
Can you explain this and what can be done to predict these things when designing?
First, the whole filter response was shifted about 300MHz right: center frequency is now 3.8 GHz instead of 3.5GHz, and the bandwith was about 300MHz instead of 700MHz.
Can you explain this and what can be done to predict these things when designing?