need help!!!! urgent microstrip antena resonance frequency

Dear all,

i need some help. now i m in a big problem in my final project about microstrip antena. i have simulate antena using microwave office and my antena work for quasi zenit satelite at resonance frequency 2.61GHz. in simulation i have good result for this return loss at -33 db, VSWR=1.2:1 and than i decide this antena for fabrication.
but when i measure the antena using network analyzer, the antena not work for 2.61G but at 2.66GHz(out of quasi zenit bw).i have check my antena patch, everything(dimension,position) same with the simulation.
i hope somebody can help me,,pleaseee


regards

Dear heviraf

Did you simulate the connector too? Look at the smith chart for 2.61 if it on real line but not 50 ohm And if the 2.66 not on the real line but closer to the center of smith you think that this point have better matching and this is the resonance freq.

plasma

Hi heviraf,

The shift in resonant frequency is not too large (less than 2%). Differences of this order can come from simulator accuracy, dielectric constant tolerance, etc. Other factors (substrate thickness tolerance, finite ground plane) have influence too. Was the measurement performed in real free space or anechoic chamber?
Regards

Z

dear all, thanks for ur attentions

these are my result

i wassimulated the antena using two kind of port(internal port & edge Port), cause i m not sure what port should i use for my antena.

it should work at 2.61G but shifted 2.66G

thanks in advance


regards