Abstract: A communication device in which the problem caused by separately providing an antenna and a filter directly connected thereto, and the problem caused by separately providing a balanced-to-unbalanced transformer, have been solved. A dielectric filter having a both-end opened &lgr;/2 resonator is constructed by providing inner-conductor forming holes in a dielectric block. An antenna is constructed by forming a radiation electrode and terminal electrodes on a dielectric block. By bonding the antenna and dielectric filter, an antenna device is achieved which has a balanced feed antenna and which performs the input-output of unbalanced signals.

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 disclosed a dielectric filter comprising: an attenuation band in proximity to a pass band; a threshold-frequency position of a determined maximum insertion loss being arranged close to a shoulder portion of a waveform exhibiting pass characteristics in which insertion losses increase in a region from the pass band to the attenuation band; temperature characteristics of a dielectric material being determined in such a manner that the shoulder portion moves toward the attenuation-band direction according to an increase and decrease in temperature. In the above dielectric filter, the deterioration of insertion-loss characteristics with respect to temperature changes is improved so that good characteristics are exhibited over a wide range of temperatures.

Abstract: A dielectric filter and a dielectric duplexer, which obviate the need to change the design of a circuit board when the dielectric filter or the dielectric duplexer are to be changed and in which the degree of freedom of design is improved, and a communication apparatus using them are constructed. Resonator holes having internal conductor formed on the respective inner surfaces thereof, and excitation holes are provided in a dielectric block, and electrodes and an external conductor are formed on the outer surface of the dielectric block. The positions of input/output coupling electrodes on the mounting surface with respect to the circuit board are aligned with the positions of the input/output coupling electrodes on the circuit board. At least one of the electrodes provided on the opening surfaces of the resonator holes is disposed in a direction which is not perpendicular to the mounting surface.

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: The present invention provides a dielectric resonator, a dielectric filter, a dielectric duplexer capable of reducing leakage of electromagnetic waves and capable of being miniaturized, and a communication apparatus incorporating the same. In each of the dielectric resonator and filter, inside a dielectric block, there is formed a L-shaped inner-conductor-formed hole having a bend at some point of the hole in a manner extending from an outer surface of the dielectric block to a surface perpendicular to the outer surface. An inner conductor is formed on the inner surface of the inner-conductor-formed hole. On the substantially entire outer surfaces of the dielectric block, there is disposed an outer conductor, with one end of the inner-conductor-formed hole open-circuited and the remaining end of the hole short-circuited. Around the edge of the open-circuited end there is formed an outer coupling electrode.

Abstract: There is provided a band pass filter comprising three or more resonant-line holes disposed in a dielectric block, a resonant line formed on each inner surface of the holes, and an outer conductor disposed on the outer surfaces of the dielectric block so that a dielectric filter is formed; wherein one end of the resonant line is a short-circuited end, and the other end thereof is an open end; the sectional area size of each of the resonant-line holes is changed at a certain point in the axial direction of the resonant-line hole; the sectional area size on the short-circuited-end side or open-end side of at least one of the plurality of resonant-line holes is made differently from those of the other resonant-line holes; and regarding the resonant-line holes symmetric with respect to a symmetry axis made at the center in a direction in which the plurality of resonant-line holes is aligned, the sectional area sizes of the short-circuited-end side or open-end side thereof are made the same so as to form coupling b

Abstract: A dielectric filter which corrects the mismatch of the resonance frequencies of resonators formed by internal conductors between a balanced terminal side and an unbalanced terminal side of the filter, and which is capable of easily obtaining a predetermined external coupling capacitance. Also, a dielectric duplexer, and a communication apparatus having the filter are obtained. Inside a dielectric block, a plurality of internal-conductor holes have different cross-sectional sizes, in which both ends thereof are open and internal conductors are formed on the inner surfaces. Also, the outer surface of the dielectric block is formed with an external conductor over four surfaces, but not on the opening surfaces of both ends of the internal-conductor holes. A pair of balanced terminals are coupled to the ends of one of the internal conductors, and an unbalanced terminal is coupled to one of the end portions of another internal conductor.

Abstract: There is provided an antenna duplexer, comprising: a plurality of resonance electrodes constituting a transmission filter and a reception filter; a dielectric member disposed betwee:n the resonance electrodes and a ground electrode; a transmission terminal, a reception terminal, and an antenna terminal, which are separated from the ground electrode in the region where the ground electrode is formed; at least one ol the transmission terminal and the reception terminal provided to make capacitive coupling between the resonance electrode of a first stage corresponding to ani In/Out stage and the resonance electrode of a second stage adjacent to the resonance electrode.

Abstract: Inner-conductor holes whose internal surfaces are coated with inner conductors are provided in a dielectric block. Input/output electrodes are provided on the outside of the dielectric block, coupled to the inner conductors by electrostatic capacitance. Gap portions are provided between the input/output electrodes and an outer conductor. The input/output electrodes may be formed to extend from a bottom surface (mounting surface) and onto a side surface of an external surface of the dielectric block. Filter characteristics are determined depending on a width or a depth of the gap portion on the side surface of the dielectric block.

Abstract: A dielectric antenna including a filter, comprising: a dielectric substrate; an antenna portion, comprising a radiation electrode having one short-circuited end and one open end and provided on or within the dielectric substrate; a filter portion comprising; at least one resonance electrode provided on or within the dielectric substrate, and a external coupling electrode in association with the resonance electrode; and the radiation electrode and the resonance electrode being coupled to each other.

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: There is disclosed a dielectric filter comprising: a plurality of resonant lines disposed in a dielectric block, in a dielectric substrate, or on a dielectric substrate; wherein the open ends of at least one adjacent pair of the resonant lines are oriented in the same direction to be combline-coupled, a first trap resonator resonant line and a signal inputting/outputting excitation line are each interdigitally coupled to one of the plurality of resonant lines, and a second trap-resonator resonant line is interdigitally coupled to the excitation line.

Abstract: A communication device in which the problem caused by separately providing an antenna and a filter directly connected thereto, and the problem caused by separately providing a balanced-to-unbalanced transformer, have been solved. A dielectric filter having a both-end opened &lgr;/2 resonator is constructed by providing inner-conductor forming holes in a dielectric block. An antenna is constructed by forming a radiation electrode and terminal electrodes on a dielectric block. By bonding the antenna and dielectric filter, an antenna device is achieved which has a balanced feed antenna and which performs the input-output of unbalanced signals.

Abstract: A dielectric filter includes a single block made of dielectric material having three or more through holes, in each of which an inner conductor is deposited, to define three or more dielectric resonators coupled in a cascade manner. Coupling holes are each formed between a pair of neighboring dielectric resonators. A bypass circuit, having a reactance component, is provided for connecting between two or more coupling holes; or for connecting the through hole of the dielectric resonator and a coupling hole; or for connecting the input terminal and one or more through holes of the dielectric resonators or the coupling holes. By selecting the holes to be interconnected and the value of the reactance of the bypass circuit, it is possible to provide a filter having a frequency characteristic in a desired format, including at least one pole at a selected point in an attenuation region thereof, without any increase in the number of dielectric resonator stages of the dielectric filter.