harmonics and parasitic passbands

Hie guys..
I have a doubt regarding bandpass filter response
how does the occurence of filter harmonics and parasitic passbands at frequencies much higher than the center frequency affect the filter's performance? in the filter which i designed with center freq 2.5GHz, there is a parasitic passband at 5GHz. will this affect the filter's performance negatively?
thank you.

Most bandpass filters gives a harmonic response. This will not affect the performance of the filter. In some cases a lowpass filter has to be added after the bandpass filter to suppress an undesired harmonic response of the bandpass filter.