Can anybody help me design a microstrip bandpass filter with a 20 MHz passband at 2,5 GHz?Any software that might help me? I have been trying ADS but the results are not understandable and correct.i have been using the filter design guide of ADS.First I design the filter with LC components and then I transform it to microstrip but it doesnot really work.Is there any other way of directly designing the filter?
Thanks
Try simulating this one with Pspice or Electronic workbench.
The "lower" end of the strip is grounded.
The bottom of the PCB is all ground.
The specific dimensions depend on the dielectric but generally the wider the "vertical" part and the closer to the ground is the connection with in/out,the narrower the bandwidth.
The limit is set by the losses in microstrip line.
To simulate this you need only two connected to each other lossy transmission lines - one short-circuited at the other end and the other-open at the other end.The first one shorter than the other and the whole length is wavelength/4.
Conect one signal source with 50 ohms internal resistance and one 50 ohms load and that's it.
This article gives you the details for a 2.6GHz 300MHz BW filter realized with microstrip hairpin. You can adjust the coupled line spacing to reduce bandwidth and lengthen the resonators to meet your fo.