Duplexers are selective components used to isolate or combine signals having different central frequencies. They form the essential core components of FDD communication systems, comprised of mobile telephony, radio transmission, broadband wireless communications and satellite communication systems. The 5G/6G market is expected to grow to more than 30 Billion USD by 2025. High performing duplexers are essential devices which will be widely used in these systems and are required to operate at very high throughputs in the mm-Wave bands. This 3-port filtering device provides good isolation between transmitter and receiver signals while maintaining a low insertion loss. Generally, the duplexers consist of two-channel filters and a common point is used to combine the two filters to form a multiport network. These duplexers provide a mechanism for transmitters and receivers to share a common antenna simultaneously. The antenna operates at both bands and the duplexer alloWS- simultaneous communication with maximum isolation between the TX and RX bands. As the mm-Wave band is getting more attention for 5G communications, duplexers are needed for 28-32 GHz band. Depending on the application scenario, the passbands for these might require wide bandwidth for higher data rates, or a narrow bandwidth for high frequency selectivity. A set of on-chip duplexers that can fulfill both these criteria for the mm-Wave band (28-30 GHz), by leveraging the Fano, EIT, and Lorentz resonance phenomena are presented. Such duplexers can be used for 5G/6G communication systems.