Improved Diode-based Frequency Selective Limiter to Use in Smart Antenna System

This paper deals with presenting a method for improving diode-based frequency selective limiter’s performance. High limiting level, low spike leakage, low recovery time, and simple design procedure made the diode-based frequency selective limiter a good option for protection of smart antenna system from high power microwave threat. Unfortunately, due to the method of nonlinear resonator realization in these limiters, in the presence of high power out of limiting band signals of each channel limiting band attenuation in passing state of these limiters increases. In this paper, band-pass filter is employed to decreasing the effect of high power out of limiting band signals on the attenuation in the passing state of limiter. By using this technique a 2-channel FSL in center frequencies of 4.2GHz and 4.6GHz, with 0dBm limiting threshold, 30dB limiting level, and 200MHz limiting bandwidth is designed. Simulation results show that using this technique can decrease the effect of out of limiting band signals on attenuation of passing state by 9dB, and increase the linearity of frequency selective limiter in the passing state of limiter.