Abstract: Under circumstances where communication devices such as mobile phones are required to be diversified, laminate filters are required to have attenuation-band characteristics which are steep on both low-frequency and high-frequency sides. The prior-art laminate filter has the problem that an attenuation band is formed only on the low-frequency side or on the high-frequency side. A laminate filter has stripline patterns that are first, second, and third resonant elements disposed on a dielectric layer, a capacitively coupled (C-coupled) pattern disposed between the first and second stripline patterns, an inductively coupled (M-coupled) pattern disposed between the second and third stripline patterns.

Abstract: A radio frequency filter having at least two dielectric resonators in juxtaposition, each resonator including a tubular dielectric body. Formed on the dielectric body of each resonator are an inner and an outer conductors and various other conductors including a terminal conductor for connection of the filter to external circuitry. In order to assure positive isolation of the terminal conductors of both resonators from each other, the outer conductors are provided with extensions which intervene between the terminal conductors for preventing then from being capacitively coupled together.

Abstract: A radio frequency filter having at least two dielectric resonators in juxtaposition, each resonator including a tubular dielectric body. Formed on the dielectric body of each resonator are an inner and an outer conductors and various other conductors including a terminal conductor for connection of the filter to external circuitry. In order to assure positive isolation of the terminal conductors of both resonators from each other, the outer conductors are provided with extensions which intervene between the terminal conductors for preventing them from being capacitively coupled together.