qustion about FDTD simulation.

Hi,
I used FDTD method to simulate a small signal microwave amplifier in 10GHz, and compared results with microwave office. in microwave office matching occures in 10GHz but in FDTD in 9.5GHz. It has a frequency shift!

It may caused by manything. Are you sure that Microwave office is enough exact?! Usually HFSS has a frequency shift too.

Regards,

AS

what would I do to be sure?
first I designed a microwave amplifier, then used a small signal model of js8851 in 10ghz, and

striplines and T junction in microwave office. and determined the substrate. then run graph of s

parameters, at 10ghz, s21=9.0db and s11=-13db. but when I used this model in fdtd, at 9.5ghz,

s21=8db, and s11=-18db. T junction in microwave office is base on circuit model but in FDTD is

base on EM model. but I think that matching dip is more deviated.

I'm not sure about length of feed lines and parameters of gaussian pulse modulated in FDTD

program, may these cause it ?

thanks,