A non-monotonic re-entrant band stop filter equalizer includes terminations and couplers. A first port of a first coupler is coupled as a first external port, and a second port of the first coupler is coupled to a band stop filter. A third port of the first coupler is coupled to a fourth port of a second coupler, and a fourth port of the first coupler is coupled to a first termination. A first port of the second coupler is coupled to the band stop filter, and a second port of the second coupler is coupled as a second external port. A third port of the second coupler is coupled to a second termination. At least one of the first directional coupler and/or second directional coupler may include at least one of a backward coupler and/or forward coupler.