Abstract: A low frequency and direct current (DC) signal blocking device includes a dielectric substrate layer; a low frequency and DC signal blocking transmission line on a first surface of the substrate layer, where the low frequency and DC signal blocking transmission line has an input end and an output end; a metal layer on a second surface of the substrate layer, where there is at least one gap on the metal layer such that the metal layer is separated into at least a first sub-region and a second sub-region, where the gap is configured to block at least one of a low frequency signal and a DC signal; the substrate layer disposed between the low frequency and DC signal blocking transmission line and the metal layer; and a metal plate, wherein a dielectric layer is disposed between the metal plate and the metal layer.