I am measuring the reflected power of a resonator for potential wireless applications. I'm pulsing the resonator with a 10.64GHz (resonate freq) pulsed waveform (10ns pulse width, 200ns period). Use an oscilloscope, it's easy to see the reflected pulse - with a maximum voltage just after the 10ns incident pulse. I've gated out the incident pulse and performed an FFT in Matlab to determine the power of the return pulse. The problem is that the power very much depends on the windowing of my FFT. As I enlarge the window, the power decreases by as much as 3-5dBm. From a practical perspective, what would be the best way to determine the reflected power of the signal? I thought about taking an FFT using ever decreasing windowing, plotting the data and determining an intercept which would be the theoretical maximum power output - but I don't see that being very practical. Thanks!