Dynamic filters are filters that can be tuned in real time, faster than the symbol rate of a signal with time constants longer than the symbol periods. Utilizing the time-varying transmission lines, which offer a low noise, broadband, and non-reciprocal behavior, dynamic filters can be constructed and employed in the rejection of self-interference in the front ends of full-duplex communications systems. Such systems pave the way for the possibility of higher-isolation and robustness compared to other prototypical forms of isolation.