A radio frequency filter employing a dual notch structure, comprising: a first cavity including a first resonator , a second cavity including a second resonator , a third cavity including a third resonator , and a fourth cavity including a fourth resonator , wherein the first cavity , the second cavity , the third cavity and the fourth cavity are arranged in a metal housing and are sequentially coupled; an input connector to receive an input signal and an output connector to provide an output signal; the first resonator of the first cavity is connected with the input connector and the fourth resonator of the fourth cavity si connected with the output connector a Capacitor, C, type notch structure formed in a predetermined region on a partition interposed between two cavities to be cross-coupled, the C type notch structure comprising a metal stick forming a capacitive coupling between respective resonators of the two cavities , the metal stick being installed in a cut off portion of the partition; and an Inductor, L, type notch structure formed along with the C type notch structure in another region of the predetermined region of the partition between the two cavities , the L type notch structure being in the form of a window formed in the partition and creating an inductance coupling between the respective resonators of the two cavities ; wherein the L type notch structure is formed at a position nearer than the C type notch structure to the input connector for receiving an input signal and the output connector for providing an output signal; wherein the two cavities are the first cavity and the fourth cavity ; and wherein the signal input to the input connector is output at the output connector after sequentially passing through the first resonator , the second resonator , the third resonator and the fourth resonator . a first cavity including a first resonator , a second cavity including a second resonator , a third cavity including a third resonator , and a fourth cavity including a fourth resonator , wherein the first cavity , the second cavity , the third cavity and the fourth cavity are arranged in a metal housing and are sequentially coupled; an input connector to receive an input signal and an output connector to provide an output signal; the first resonator of the first cavity is connected with the input connector and the fourth resonator of the fourth cavity si connected with the output connector a Capacitor, C, type notch structure formed in a predetermined region on a partition interposed between two cavities to be cross-coupled, the C type notch structure comprising a metal stick forming a capacitive coupling between respective resonators of the two cavities , the metal stick being installed in a cut off portion of the partition; and an Inductor, L, type notch structure formed along with the C type notch structure in another region of the predetermined region of the partition between the two cavities , the L type notch structure being in the form of a window formed in the partition and creating an inductance coupling between the respective resonators of the two cavities ; wherein the L type notch structure is formed at a position nearer than the C type notch structure to the input connector for receiving an input signal and the output connector for providing an output signal; wherein the two cavities are the first cavity and the fourth cavity ; and wherein the signal input to the input connector is output at the output connector after sequentially passing through the first resonator , the second resonator , the third resonator and the fourth resonator . <EOS>