behavioral modeling of Gm-C integrator

Hi,

I am doing behavioral modeling of IR-UWB receiver front end using matlab. As part of this project I want to see response of integrator in RF-front end.

What are the key aspects system designer must look at for behavioral modeling first order integrator with (unity gain bandwidth)UGBW 2GHz, DC gain should as high as possible and cutoff frequency must be very low.
I am solving this by using tf=G_dc*Wp/s+Wp where Wp is cutoff freq and G_dc --dc gain.

Here How can i specify UGBW in the transfer function.

thanks for help.