Abstract: A dielectric filter having a dielectric body made of dielectric material and having an outer surface including first and second end faces; an external conductor disposed on the outer surface of the dielectric body; at least one hole extending through the dielectric body between the two end faces, the at least one hole having a respective inner surface; the at least one hole having a pair of internal conductors respectively provided in the corresponding hole and conductively connected to the external conductor at respective ends of the corresponding hole, a respective non-conductive portion at the inner surface of the corresponding hole being spaced from both ends of the respective hole and thereby separating the corresponding pair of internal conductors and defining a capacitance between the corresponding pair of internal conductors; the first end face of said dielectric body being closer to the non-conductive portion at the inner surface of the corresponding hole than the second end face; the first end face

Abstract: A dielectric duplexer contains a substantially-rectangular-parallelepiped-shaped dielectric block. The dielectric block includes plated through holes having inner conductors formed thereon. An outer conductor is formed on an exterior surface of the dielectric block. An input/output terminal is formed by an outer-conductorless portion separating the input/output terminal from the outer conductor of the plated through holes and is defined by an outer-conductorless portion extending from a short circuit face of the dielectric block to a mounting surface thereof. An antenna excitation hole is formed as a through-hole in the same axial direction as that of the plated through holes in the dielectric block. The antenna excitation hole contains an electrode which is coupled to the antenna terminal. Two electrodeless portions, each having a predetermined shape, are formed between open edges of two plated through holes and a top face of the dielectric block.

Abstract: A method of forming metallization patterns on a block of dielectric material wherein the entire surface area of the dielectric block is encased with a conductive material and unwanted conductive metal is ablatively etched from a designated surface area of the dielectric block to form desired metallized circuit patterns. The invention also comprises a filter and a duplexer formed by the method of the present invention.

Abstract: In a dielectric filter, from the top surface to the bottom surface of a substantially rectangular dielectric block, inner-conductor holes are formed. On the inner surfaces of the inner-conductor holes, inner conductors are formed except where non-conductor portions are formed in proximity to one of the top and bottom surfaces, in which the apertures of the inner-conductor holes are formed. On the outer surface of the dielectric block, an outer conductor is formed substantially over the entire outer surface, and input and output electrodes isolated from the outer conductor are coupled with the non-conductor portions in the respective inner-conductor holes at the ends of the dielectric block in the direction of array of the inner-conductor holes.

Abstract: A dielectric filter includes a dielectric block having a plurality of a outer surfaces and a plurality of through holes extending through the dielectric block. Inner conductors are located on respective inner surfaces of the through holes and an outer conductor is located on a plurality of the outer surface of the dielectric block. An input-output electrode is formed on at least one of the outer surfaces of the dielectric block and is faced from the outer conductor by first conductor-less portion. A rectangular second conductor-less portion extends from the first conductor-less portion to generate an attenuation pole at a desired frequency positioned at a higher frequency side of the band pass of a transmission signal.

Abstract: The present invention relates to a fastener means for securing a center conductor (23) in a cavity filter and for enabling the center conductor to be secured mechanically in a stable fashion and with good electric contact between itself and the bottom 22 of the cavity. The inventive fastener means comprises a center conductor and a fastener element (25, 26) provided integral therewith to form a single-piece structure, which structure may have the form of a screw with the center conductor (23) as the screw head at one end and screw threads (26) at the other end. The contact surface between the fastener means and the cavity bottom is surface-treated with a material of low resistivity, such as silver for example.

Abstract: A low-profile dielectric filter includes a dielectric substrate having an opening that extends from a top to a bottom surface of the substrate. A bottom electrode is bonded to the bottom surface of the dielectric substrate, covering the opening to define a depression. Dielectric resonators are mounted in the depression, the bottom electrode serving as a weight-bearing support surface for the dielectric resonators. A plurality of electric devices, such as a resistor, a diode and an air-core coil, are mounted to the dielectric substrate, and a top electrode is mounted to the top surface of the dielectric substrate. The top electrode connects the dielectric resonators and the electric devices. A cover is placed so as to cover the area in which the resonators are mounted.

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: 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 method of producing filters using lower unloaded Q factor components than filters with the same performance characteristics but requiring higher unloaded Q factor components is disclosed. The method includes the steps of defining a desired filter characteristic and applying an algorithm which provides a filter having infinite Q factor elements and having a theoretical characteristic corresponding to the desired characteristic transformed to a compensate for the difference between finite Q factor and infinite Q factor elements.

Abstract: A dielectric filter which has suitable attenuation characteristics and which readily exhibits desired characteristics. First, second and third inner-conductor holes having an inner conductor on each of the surfaces thereof are formed inside a dielectric block having an outer conductor on the outer surface thereof. First and second I/O electrodes extend from opposing side-surfaces to the undersurface of the dielectric block and are separated from the outer conductor. The side-surfaces are orthogonal to the direction in which the inner-conductor holes are arrayed in the dielectric block, and the undersurface is a mounting surface for facing a mounting board. The first I/O electrode extends from one of said side-surfaces near the first inner-conductor hole, to a position beyond a remote side of the second inner-conductor hole, that is, the side near the third inner-conductor hole.

Abstract: A dielectric filter includes a dielectric block. A plurality of inner-conductor holes, each having an inner conductor on the surface thereof, extend from a first open surface to the opposing surface through the inside of the dielectric block. On the outer surface of the dielectric block, an outer conductor is formed, except on the first open surface. On the first open surface, projections are provided between respective pairs of inner-conductor holes. Coupling electrodes are formed on the side surfaces of the projections and extending onto the first open surface of the dielectric block, where they connect to the inner conductors. On the outer surface of the dielectric block, input/output electrodes are formed such that they couple to the coupling electrodes.

Abstract: There is provided a dielectric filter comprising: a dielectric block; a plurality of resonance-line holes aligned therein; a resonance line disposed on an inner surface of each of the resonance-line holes; and an outer conductor disposed on an outer surface of the dielectric block; wherein one end of the resonance-line hole is a short-circuited end; a sectional area of at least one of the resonance-line holes is changed at a predetermined portion; the predetermined portion of at least one of the resonance-line holes along to the axial direction of the resonance-line hole and at a side opposed to the adjacent resonance-line hole. According to the above structure, the coupling between specified resonance lines among the adjacent resonance lines can be independently determined without changing a pitch for aligning the resonance-line holes.

Abstract: A dielectric filter comprising a dielectric block having a substantially rectangular solid shape and having an outer-conductor; a plurality of inner-conductor-coated holes disposed inside the dielectric block; the end portion of at least one inner-conductor-coated hole being an open-circuited surface on which the outer-conductor is not disposed, and an input-output electrode being capacitance-coupled to the vicinity of the end portion of that inner-conductor-coated hole; and both end portions of another inner-conductor-coated hole, which is not capacitance-coupled to an input-output electrode, are covered by the outer-conductor, and an inner-conductorless portion is provided inside the hole. Preferably an end portion of the other hole either is sunken below or protrudes above the open-circuited surface.

Abstract: There is a manufacturing limit on how small ceramic coaxial resonators can be produced, which leads to a limit on the frequency of resonance for these resonators. One technique to double the effective frequency of a ceramic coaxial resonator is to couple each end of a resonator to a Colpitts oscillator, the oscillators being balanced and out-of-phase by 180°. During operation, the resonator is effectively divided in half with a virtual ground forming in the center. This allows a single resonator to operate as two resonators of half the original size. Hence, the oscillation frequency for each of these balanced oscillators is doubled when compared to the frequency of similar oscillators that have separate ceramic coaxial resonators of similar size. If this technique is further implemented within a push-pull design tuned to the third harmonic, the output oscillation frequency becomes six times that of an oscillator using a separate ceramic coaxial resonator of similar size.

Abstract: The invention provides a coaxial resonator which can be electrically connected to an inductance or like electric element easily to reduce the number of work steps for mounting and the number of parts, and a dielectric filter and a dielectric duplexer which comprise the resonator and which can be compacted and installed in a diminished space. The coaxial resonator comprises a dielectric block having a through bore extending through opposite end faces thereof, and a conductor layer formed over an outer peripheral surface of the block except one end face thereof and over a block inner surface defining the through bore for causing electromagnetic waves to resonate within the dielectric block. A lead-equipped electric element has its lead inserted in the through bore and electrically connected to the conductor layer over the bore-defining inner surface with a braze filler metal or electrically conductive adhesive, the lead being fixed in the through bore.

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: The present invention is a filter and a method of making a filter to remove unwanted frequency harmonics associated with current filters. The filter is made up of resonators, such that the filter resonates a design frequency. Whereby, at least two resonators are coupled together between an input and an output and at least one of the resonators is of a different design from other resonators, such that the resonator of a different design resonates the same design frequency as the other resonators and resonates different higher order harmonic frequencies than the other resonators. The present invention also provides methods of improving skirt response for a filter, as well as other response properties of the filter. One way to improve the filter's properties is where at least one of the resonators in a filter is reversed in orientation as compared to the other resonators.

Abstract: A filter includes a first end, a second end, a conducting casing, at least one central conductor, and connecting devices at each of the ends, the casing extending along an imaginary axis and intended to accommodate the conductor along this imaginary axis. The conductor is provided with capacitance generating portions and inductance generating portions. The connecting device at the first end of the filter includes a first connecting member connected to the casing and a second connecting member connected to the conductor, and the connecting device at the second end of the filter includes a third connecting member connected to the casing and a fourth connecting member connected to the conductor. Both the second and the fourth connecting members are provided integrally with the conductor.

Abstract: There is disclosed a duplexer comprising: a first external terminal; a second external terminal; an antenna terminal; a first frequency variable filter electrically connected between the first external terminal and the antenna terminal, and composed of at least one resonator and a reactance element electrically connected to the resonator and capable of being voltage-controlled; a second frequency variable filter electrically connected between the second external terminal and the antenna terminal, and composed of at least one resonator and a reactance element electrically connected to the resonator and capable of being voltage-controlled; the predetermined reactance element of the first frequency variable filter being in the on state when the reactance element of the second frequency variable filter is in the on state.

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: A ceramic block filter is designed with a shunt transmission line to attenuate third harmonics. A metallized belt is printed on the top surface of the filter along its edges so that it is connected to the metallized ground of the side surfaces. Along one edge an unmetallized line is left along one edge of the filter, whose ends are grounded. The unmetallized line is designed with a length greater than one-half of the length of the metallized belt, but smaller than the length of the metallized belt. The length and width of the unmetallized line are design choices for the specific frequencies sought to be attenuated.

Abstract: Grooves are formed on the connection faces of the dielectric basic plates as a dielectric resonator, and also, an internal conductor is provided on the inside face, and coupling electrodes are formed on the other dielectric basic plate. These three dielectric basic plates are connected so that the coupling electrode effects capacity connection between internal conductors and the coupling electrode effects capacity connection between the internal conductors, whereby an earth electrode (external conductor) can be formed on almost full face on the reverse face side of the dielectric basic plate and the reduction of Qo of the resonator and the electromagnetic field leakage can be prevented.

Abstract: The present invention is a filter and a method of making a filter to remove unwanted frequency harmonics associated with current filters. The filter is made up of resonators, such that the filter resonates a design frequency. Whereby, at least two resonators are coupled together between an input and an output and at least one of the resonators is of a different design from other resonators, such that the resonator of a different design resonates the same design frequency as the other resonators and resonates different higher order harmonic frequencies than the other resonators. The present invention also provides methods of improving skirt response for a filter, as well as other response properties of the filter. One way to improve the filter's properties is where at least one of the resonators in a filter is reversed in orientation as compared to the other resonators.

Abstract: A dielectric filter, having a dielectric block with an outer surface including first and second end surfaces and a side surface extending between the first and second end surfaces; an external conductor disposed on the outer surface of the dielectric block, the external conductor substantially completely covering the outer surface; at least one hole extending through the dielectric body between the first and second end surfaces, the at least one hole having an inner surface; the at least one hole having a respective pair of internal conductors disposed on the corresponding inner surface thereof and conductively connected to the external conductor respectively at the first and second end surfaces, a respective non-conductive portion at the corresponding inner surface being spaced from both of the end surfaces and thereby separating the corresponding pair of internal conductors and defining a respective capacitance between the corresponding pair of internal conductors; a predetermined portion of the side surfac

Abstract: The objcet of the present invention is to provide a microwave filter having a shield for electromagnetic interference shielding, wherein the filter is adaped for use in a radio frequency circuitry located in a stage next to an antenna for a radio communication system, such as a mobile communication system, a portable communication system, satellite communication system, and IMT-2000, for passing signals having desired frequencies while removing signals having frequencies having undesired frequencies. According to the present invention, there is provided a microwave filter for electromagnetic interference shielding, comprising a block of dielectric material plated with a metal with the exception of one surface, a plurality of resonators contained within the dielectric block, and a shield fixed on the surface which is not plated, wherein the shield has at least an alignment window for securing the easy alignment between the dielectric block and the shield through a visual observation.

Abstract: A filter and a method of making a filter to remove unwanted frequency harmonics associated with current filters. The filter is made up of resonators, such that the filter resonates a design frequency. Whereby, at least two resonators are coupled together between an input and an output and at least one of the resonators is of a different design from other resonators, such that the resonator of a different design resonates the same design frequency as the other resonators and resonates different higher order harmonic frequencies than the other resonators. The present invention also provides methods of improving skirt response for a filter, as well as other response properties of the filter.

Abstract: A dielectric device is provided which comprises a dielectric resonator element having a plurality of resonators arranged in parallel with each other, a multilayer circuit element having conductive patterns constituting a coupling circuit, the conductive patterns being laminated vertically while alternating with dielectric layers, the circuit element being rectangular and having a pair of opposite vertical side surfaces, the coupling circuit having first connecting ends disposed at the first vertical side surface and second connecting ends disposed at the second vertical side surface, a plurality of vertical conduction grooves disposed at the first vertical side surface, the conduction groove having open upper ends and electrically connected to the first connecting ends of the coupling circuit, a plurality of metallic terminal members fitted in respective through holes of the resonators and thereby electrically connected to inner conductors of the resonators while being fitted in the conduction grooves and the

Abstract: A receive/transmit multi-cavity filter having input and output filter sections coupled to an antenna by a single cavity.

Abstract: The invention provides a composite dielectric filter device that can easily improve the isolation characteristics between mutually adjacent filters, even when using a compact dielectric block to miniaturize the entire configuration of the device. The invention also provides a communication apparatus incorporating the filter device. In the filter device, inner conductor holes are arranged inside a single dielectric block, and an outer conductor is formed on outer faces of the dielectric block. Additionally, an outer-conductor-free portion is formed at the boundary between a transmission filter and a reception filter formed by the inner conductor holes.

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: A duplexer using a dielectric block and having stepped impedance resonators is disclosed. The duplexer comprising open ended resonators arranged in a front side of the dielectric block, shorted resonators arranged in a rear side of the dielectric block, first grooves for controlling receiving coupling at the receiving filter, second grooves for controlling transmitting coupling at the transmitting filter, and a plurality of recesses formed at the bottom of the dielectric block, extending from a first aperture of the open ended resonators to a second aperture of the shorted resonators. The duplexer according to this invention is miniaturized by excluding external elements and has excellent attenuation characteristics, and is being manufactured by simple processes.

Abstract: A duplexer comprising: &lgr;/4-type dielectric coaxial resonators constituting a transmitting-side filter; &lgr;/4-type dielectric coaxial resonators constituting a receiving-side filter; and coupling elements for coupling said resonators; wherein the dielectric coaxial resonators constituting the transmitting-side filter and the dielectric coaxial resonators constituting the receiving-side filter are placed in parallel; and the open end surfaces of the dielectric coaxial resonators constituting the transmitting-side filter and the open end surfaces of the dielectric coaxial resonators constituting the receiving-side filter are disposed in opposite directions, and/or are alternately disposed side-by-side.

Abstract: High frequency dielectric ceramic compositions having a dielectric constant (∈r) of 30 to 50, a Q value of 15,000 or more at 1 GHz, and a temperature-dependent factor of resonant frequency (&tgr;f) which can be arbitrarily controlled centering around 0 (ppm/° C.) have a main crystal of the perovskite type crystal phase by (1−x)MeTiaO1+2a—xLn(Ma1/2Mb1/2)bO(3+3b)/2, wherein Ln is a rare earth element, Ma is at least one of Mg and Zn, Mb is at least one of Sn and Zr, Me is at least one of Ca and Sr, x is the mole fraction, and 0.95≦a≦1.05, 0.9≦b≦1.05 and 0.3≦x≦0.5.

Abstract: A band pass filter is constituted of a dielectric block 2 having through holes 5 formed from one surface to the opposite surface and a single layered dielectric plate 3 joined to the dielectric block 2 such that the back surface thereof faces the one surface of the dielectric block 2.

Abstract: The invention comprises a filter consisting of resonators (330, 320, . . . ) with a conducting housing, particularly to be used in networks operating on microwave frequencies. The couplings between the resonators are realised outside the conducting filter housing with the aid of a printed board (310) over a wall (306) of the housing. For a particular coupling a conductor strip (311) extending from one resonator to another is formed on the printed board, and openings (335, . . . ) are made in the resonator walls at the ends of the strips. In order to strengthen the coupling a coupling element (343) extending into the resonator cavity can be fastened as an extension of the strip. The filter connectors (301, . . . ) are also fastened to the printed board. The open filter housing (305) and the inner conductors (331, 341, . . . ) or the resonators can be made as a homogenous body. The manufacturing costs and the tuning costs of a filter according to the invention are relatively low.

Abstract: There provided a dielectric filter unit comprising: a dielectric block having a pair of opposing end surfaces; a plurality of resonator holes respectively passing through the pair of opposing end surfaces of the dielectric block and having a large-sectional area portion and a small-sectional area portion connected to the large-sectional area portion; an inner conductor disposed on the inner surface of each of the resonator holes; an outer conductor disposed on the outer surface of the dielectric block; at least one of the resonator holes constituting a first filter; at least one of the remaining resonator holes constituting a second filter; and the area ratio of the large-sectional area portion to the diameter of the small-sectional area portion of the resonator hole of the first filter being different from the area ratio of the large-sectional area portion to the diameter of the small-sectional area portion of the resonator hole of the second filter.

Abstract: The invention provides a filtering device of the transmission-reception switched type which can be constructed in a form with a reduced size at a low cost without having to use circuit elements such as a capacitor, a coil, and a transmission line forming a phase shift circuit which are not essential to the filtering device. Inner conductors serving as distributed-parameter resonance lines are formed in a dielectric block. There is provided a coupling line coupled with particular inner conductors. The open-circuited ends of these particular inner conductors are connected to an outer conductor via corresponding diode switches so that transmission and reception filters are switched from each other when either diode switch is selectively turned on.

Abstract: A radio frequency mechanical filter (10) of the resonant type employs a plurality of parallel spaced-apart resonators (40) disposed within a housing (16) defining a cavity. The resonators are supported at their first ends (46) to one wall (20) of the housing (16), with the remaining ends of the resonators being unsupported. A TEFLON support bracket (12) is disposed across the resonators (40) at points between the ends (44, 46) of the resonators. In one form, the support bracket (12) is movable along the length of the resonators to change the center frequency and bandwidth response of the filter.

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: The invention provides a dielectric filter, comprising: a dielectric block having a first end face and a second end face and side faces extending therebetween; a plurality of resonator holes and at least one external coupling hole respectively passing through both end faces; inner conductors provided on inner faces of the resonator holes and the external coupling holes; an external conductor provided on the outer faces of the dielectric block; concavities provided in formation regions of the external coupling holes on the first and the second end face and in the short-circuiting regions of the resonator holes; and the external conductor being removed except from the portions of the concavities in the first end face and the second end face, thereby forming open faces of the resonator holes on the first end face and the second end face.

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, having a dielectric block with an outer surface including first and second end surfaces and a side surface extending between the first and second end surfaces; an external conductor disposed on the outer surface of the dielectric block, the external conductor substantially completely covering the outer surface; at least one hole extending through the dielectric body between the first and second end surfaces, the at least one hole having an inner surface; the at least one hole having a respective pair of internal conductors disposed on its corresponding inner surface and conductively connected to the external conductor respectively at the first and second end surfaces, a respective non-conductive portion at the corresponding inner surface being spaced from both of the end surfaces and thereby separating the corresponding pair of internal conductors and defining a respective capacitance between the corresponding pair of internal conductors; a predetermined portion of one of the first and se

Abstract: In an antenna-sharing device, a transmission filter is electrically connected between a transmission terminal and an antenna terminal, and a reception filter is electrically connected between a reception terminal and the antenna terminal. A signal pattern and a ground electrode are formed on a resonator-mounting surface of a circuit substrate. On the ground electrodes, the resonators constituting the transmission filter are integrally soldered and the resonators constituting the reception filter are integrally soldered. On the mounting surface of the circuit substrate, a transmission filter ground electrode and a reception filter ground electrode are formed. Both ground electrodes are isolated from each other by a gap (slit), and are disconnected from each other.

Abstract: The open faces of resonator holes of a dielectric filter are capable of being formed with high dimensional precision by a simple process, by which a coupling between resonators and an external coupling can easily be adjusted. In addition, a duplexer including the dielectric filter, and a communication apparatus including at least one of the dielectric filter and the duplexer are provided. The dielectric filter includes a dielectric block having protrusions on the upper surface of a substantially rectangular-parallelepiped base. Resonator holes are disposed by penetrating from the end faces of the protrusions to the lower surface of the base that opposes the end faces. External coupling holes are disposed by penetrating the opposing upper and lower surfaces of the base. An inner conductor is formed on the inner surface of each hole, and an outer conductor is formed on the substantially entire outer surface of the dielectric block except the end faces of the protrusions.

Abstract: A dielectric filter includes a dielectric block having substantially a rectangular parallelepiped shape, a plurality of internal-conductor-formed holes provided substantially parallel to one another in the dielectric block, each including an internal conductor formed on the internal surface thereof, an external conductor formed on the external surface of the dielectric block, and an input/output electrode formed on the external surface of the dielectric block.

Abstract: A high-frequency dielectric ceramic compact is provided which has a relative dielectric constant (∈r) of about 20 or less and a Q value of about 20,000 or more at 1 GHz, in which the temperature coefficient (&tgr;f) can be optionally controlled at about 0 (ppm/° C.). When the compact of the dielectric ceramic compact is represented by the formula aBaO.bMeO.cSbO3/2, 0.476≦a≦0.513, 0.160≦b≦0.175, and 0.324≦c≦0.350. In addition, when the compact of the dielectric ceramic compact is represented by the formula dBaO.eMeO.fSbO3/2.gTiO2, 0.476≦d≦0.513, 0.100≦e≦0.175, 0.200≦f≦0.349, and 0<g≦0.200.

Abstract: A dielectric filter capable of easily obtaining desired filter characteristics by strongly coupling mutually adjacent resonators with high accuracy even when reducing the height of the entire filter. In this filter, inside a dielectric block, there are disposed inner-conductor-formed holes in which inner conductors are formed on the inner surfaces of the holes. Coupling electrodes are arranged on an outer surface of the dielectric block and are electrically connected to the inner conductors. Additionally, the coupling electrodes are extended, for example, from the edge of an opening surface of the dielectric block which contains the open ends of the inner-conductor-formed holes, onto a side surface which is disposed parallel to a direction in which the inner-conductor-formed holes are aligned. The invention also provides a duplexer and a communication apparatus using the dielectric filter.

Abstract: A dielectric filter and a dielectric duplexer have simple structures, in each of which the resonance frequency of a TE mode is controlled in such a manner that no TE-mode spurious response occurs in a band requiring attenuation. Specifically, the distance between the central position of each of inner-conductor-formed holes and a widthwise line of a dielectric block is set to be two times or more than the distance between the central position of each of the holes and a lengthwise line thereof. With this arrangement, the resonance frequency of a spurious mode such as a TE101 mode is shifted to the low-frequency side to deviate the resonance frequency of the spurious mode from a band requiring attenuation, for example, from a band near the second-order harmonic of a TEM mode, as a mode to be used. In addition, a communication apparatus is formed by using one of the filter and the duplexer described above.