Pulse distortion through a lossy plasma medium

Signal degradation through a lossy ionospheric plasma was studied. The channel was modeled by a transfer function consisting of an attenuation factor and a phase-distortion function. For narrowband signals the transfer function can be greatly simplified. By the saddle-point integration technique an asymptotic solution for the output waveform of a rectangular pulse transmitted through this lossy medium was derived. It shows that when the absorption rate is high and finite bandwidth is taken into account, the frequency-dependent collisional absorption also plays an important role in waveform distortion.