Abstract: A dielectric filter including: a &lgr;/2 resonator for generating resonance of ½-wavelength at a predetermined frequency, having both ends open-circuited or short-circuited; and a pair &lgr;/4 resonators respectively for generating resonance of ¼-wavelength at a frequency substantially equal to the predetermined frequency, each having one end open-circuited and the other end short-circuited; wherein the pair of &lgr;/4 resonators are disposed in proximity to each of both ends from the vicinity of the center of the &lgr;/2 resonator; a terminal coupling to the &lgr;/2 resonator is provided as an unbalanced terminal; and terminals coupling to the pair of &lgr;/4 resonators is used as a balanced terminal. In the above filter, the balanced-type input/output of signals can be performed without using a balun.

Abstract: There is disclosed a dielectric filter comprising: a &lgr;/2 resonator for generating resonance of ½-wavelength at a predetermined frequency, having both ends open-circuited or short-circuited; and a pair of &lgr;/4 resonators respectively for generating resonance of ¼-wavelength at a frequency substantially equal to the predetermined frequency, each having one end open-circuited and the other end short-circuited; wherein the pair of &lgr;/4 resonators are disposed in proximity to each of both ends from the vicinity of the center of the &lgr;/2 resonator; a terminal coupling to the &lgr;/2 resonator is provided as an unbalanced terminal; and terminals coupling to the pair of &lgr;/4 resonators is used as a balanced terminal.

Abstract: There is disclosed a dielectric filter comprising: a &lgr;/2 resonator for generating resonance of ½-wavelength at a predetermined frequency, having both ends open-circuited or short-circuited; and a pair of &lgr;/4 resonators respectively for generating resonance of ¼-wavelength at a frequency substantially equal to the predetermined frequency, each having one end open-circuited and the other end short-circuited; wherein the pair of &lgr;/4 resonators are disposed in proximity to each of both ends from the vicinity of the center of the &lgr;/2 resonator; a terminal coupling to the &lgr;/2 resonator is provided as an unbalanced terminal; and terminals coupling to the pair of &lgr;/4 resonators is used as a balanced terminal. In the above filter, the balanced-type input/output of signals can be performed without using a balun.

Abstract: A dielectric filter, a dielectric duplexer, and a communication apparatus using them allow balanced input and/or output to be implemented without requiring a balun. Using a dielectric block, two &lgr;/2 resonators are individually formed using either inner-conductor-forming openings with inner conductors therein, or stripline-type conductors, both of said conductors having both ends open-circuited, and said conductors being capacitively coupled together. Terminal electrodes coupled to the vicinities of two open-circuited ends of one of the resonators are used as balanced terminals on one side, and terminal electrodes coupled to the vicinities of the two open-circuited ends of the other one of the resonators are used as balanced terminals on the other side.

Abstract: Inner conductor formation holes having inner conductors formed on the inner walls thereof are formed in a dielectric block. Both of the ends of one of the inner conductors are open and led out as terminal electrodes which function as balanced ports. Both of the ends of another inner conductor are connected to an outer conductor to be grounded, and the center portion of the inner conductor between the ends is led out as a terminal electrode which functions as an unbalanced port. The circuit can also be realized with striplines or microstriplines on a dielectric substrate. Thus, a balanced-unbalanced converter having these terminal electrodes as balanced and unbalanced ports is formed.

Abstract: A dielectric filter and a dielectric duplexer adapted to two frequency bands formed by using a single component are disclose, in addition to a communication apparatus using the same. In this case, since a dielectric block used as the single component can be easily molded and grasped, production efficiency can be enhanced. The dielectric duplexer adaptable to two frequency bands is formed by disposing inner-conductor-formed holes acting as &lgr;/2 resonators and &lgr;/4 resonators in the single dielectric block.

Abstract: A &lgr;/2 resonator comprises an inner conductor formed hole having an inner conductor with both open-ends, formed therein, and &lgr;/4 resonators comprise inner conductor formed holes having inner conductors with one short-circuited ends and the other open ends, respectively. The resonators are coupled, whereby a terminal electrode connected to the vicinity of the one open end of one of the &lgr;/4 resonators functions as an unbalanced terminal, and terminal electrodes connected to both open ends of the &lgr;/2 resonator function as balanced terminals.

Abstract: There is provided a dielectric filter comprising: a dielectric block; a plurality of resonance lines aligned substantially in parallel in the dielectric block; and a conductor line disposed in the dielectric block so as not to be parallel to the longitudinal direction of the resonance lines, the conductor line being served as a device having an inductance component which is connected to a circuit comprising the resonance lines.

Abstract: There is provided a dielectric filter, comprising: a plurality of resonance lines aligned in a dielectric block, in a dielectric subtrate or on a dielectric substrate; a plurality of input-output units respectively coupled to the plurality of resonance lines; at least one of the input-output units comprising a first external terminal capacitively coupled to one of the plurality of resonance lines, an external coupling line coupled to the one of the plurality of resonance lines to which the first external terminal is capacitively coupled, and a second external extending from an end of the external coupling line. In the above dielectric filter, input and output of signals are performed in a two-terminal type or a balance type, without using a balun.

Abstract: On the internal surface of each of the through-holes formed in a dielectric block, an internal conductor is formed, while on the external surface except the top surface, an external conductor is formed. The internal conductors, together with the external conductor and the dielectric block, form dielectric resonators with 1/4-wavelength using the top and bottom surfaces of the dielectric block as an open surface and a short surface, respectively. Each of the through-holes has a large-diameter hole portion and a small-diameter hole portion and also has a coupling adjustment hole portion for the purpose of a fine adjustment of electromagnetic coupling between adjacent the dielectric resonators.

Abstract: The invention provides a technique of adjusting the mutual capacitance of resonant through-holes in a dielectric filter while maintaining the shape of input/output electrodes constant without causing a change in the external capacitance.

Abstract: A ?/2 resonator comprises an inner conductor formed hole having an inner conductor with both open-ends, formed therein, and ?/4 resonators comprise inner conductor formed holes having inner conductors with one short-circuited ends and the other open ends, respectively. The resonators are coupled, whereby a terminal electrode connected to the vicinity of the one open end of one of the ?/4 resonators functions as an unbalanced terminal, and terminal electrodes connected to both open ends of the ?/2 resonator function as balanced terminals.