Abstract: A microwave filter includes at least two dielectric resonators, a transmission microstrip, and at least one lateral microstrip constituting a branch connected to the transmission microstrip. Each lateral microstrip is coupled to at least one dielectric resonator to resonate therewith. The filter is compact and can therefore be incorporated into the housing of a microwave antenna, in particular a multiband antenna for mobile telephone networks.

Abstract: A dielectric substrate, a transistor, which is an active device, a varactor diode, which is a frequency-variable device, are mounted on one main surface of a package substrate to configure an oscillator. The dielectric substrate is made from a large-dielectric-constant dielectric having high temperature stability. A microstrip-line resonator is formed by thin-film-electrode forming. The microstrip-line resonator and the transistor constitute an oscillating circuit.

Abstract: A low noise block down converter accommodates two local oscillators within one shielding chamber in a metal shielding box and has a conductive bar provided between two dielectric resonators included in the local oscillators respectively. The conductive bar prevents electromagnetic coupling between the two dielectric resonators. Therefore, the device dimension can be made small compared to the conventional case in which two local oscillators are completely separated from each other by a metal wall.

Abstract: The present invention provides a modulator which has a high degree of modulation and a good modulation sensitivity. The modulator comprises an oscillating circuit and a resonator portion, and this resonator portion comprises a reflective circuit board, a coupling line which is disposed on the reflective circuit board, a coupled load which is coupled to one end of the coupling line, a dielectric resonator which is disposed on the reflective circuit board and which is magnetically coupled with the coupling line, a window portion which is formed in the undersurface of the reflective circuit board directly beneath the coupling line, a waveguide resonator which is disposed on the undersurface of the reflective circuit board in the area that includes the window portion, and which is magnetically coupled with the coupling line, and a varactor diode which is inserted between the opposite signal conductor surfaces and of the waveguide resonator, and to which the input modulating signal terminal is connected.

Abstract: A planar dielectric integrated circuit is provided such that energy conversion loss between a planar dielectric line and electronic components is small and that impedance matching between them can be easily obtained. A planar dielectric line is provided by causing two slots to oppose each other with a dielectric plate interposed in between, a slot line and line-conversion conductor patterns are provided in the end portions of the planar dielectric line, and an FET is disposed in such a manner as to be extended over the slot line.

Abstract: A dielectric filter has an input and an output for a microwave signal; a rotationally symmetrical single-piece dielectric resonator body that is inducible by a microwave signal to execute electromagnetic oscillations, the resonator body having two different-sized basal surfaces perpendicular to a rotational symmetry axis, the resonator body also having side surfaces which connect the basal surfaces along straight lines.

Abstract: The invention is a dielectric resonator in the shape of a truncated cone and variations with a longitudinal through hole. The truncated cone shape physically displaces the H11l mode from the TE mode in the longitudinal direction of the cone. Particularly, the TE mode tends to concentrate in the base of the cone while the H11 mode tends to concentrate at the top of the cone. By truncating the cone so as to eliminate the portion of the cone where the H11 mode field exists, yet keep the portion of the cone where the TE mode exists, the H11 mode can be virtually eliminated while having no effect on the magnitude of the TE mode.

Abstract: In order to prevent filter characteristics from being deteriorated due to generation of a spurious pulse is unnecessary resonance at a high level in a passing band at the frequency in a microwave region used in a portable telephone system or the like, at least two types of dielectric resonators having different frequency characteristics in unnecessary harmonic modes except for a main mode near the passing band of a filter are arranged in spaces partitioned by partition walls in a shielding unit constituted by a metal case and a lid, so that a dielectric filter which can obtain preferable spurious suppressing characteristics.

Abstract: A high frequency dielectric ceramic composition includes: as a major component a composition which contains a rare earth element (Re), Al, Sr, and Ti as metal elements and has a composition formula expressed by a molar ratio of aRe2O3—bAl2O3—cSrO—dTiO2 in which a, b, c, and d satisfy the following formula; 0.113≦a≦0.172, 0.111≦b≦0.171, 0.322≦c≦0.388, 0.323≦d≦0.396, and a+b+c+d=1.000; and 0.01 to 2 parts by weight on a Fe2O3 conversion basis of Fe as an element, based on 100 parts by weight of the major component.

Abstract: A method for affixing a resonator to a printed circuit board is provided. The method uses a thin metal film which may be affixed to a surface of a stand off, or directly to a surface of a resonator. The metalized surface may be affixed to a printed circuit board using a molten agent with a surface tension which withstands the downward force exerted by the puck's weight. The metalized surface may be affixed to a printed circuit board using a solder paste and the solder is allowed to reflow. The surface tension of the molten solder causes the resonator (or resonator puck) to self-center, ensuring proper placement and eliminating the need for repositioning. Since the resonator is not positioned using traditional glues which are subject to shifting during transportation or curing, then the resonator is not subject to shifting, eliminating the need to reposition the resonator after the resonator becomes fixed.

Abstract: The present invention provides a dielectric waveguide filter comprising a plurality of dielectric waveguide resonators in the form of rectangular parallelepiped-shaped blocks aligned as a single main body having opposite ends defined by respective the end blocks located thereat, and a pair of input and output electrodes provided in the end blocks, respectively. Each of the end blocks is formed with a protruding portion including a dielectric substance extended from that therein. A conductive strip line extending from the bottom surface of corresponding one of the end blocks to the edge region of the bottom surface of corresponding one of the protruding portions. The bottom surfaces have a region where the dielectric substance in contact with the both sides of the conductive strip line is exposed to outside. The conductive strip lines are coupled with micro-strip lines or co-planer lines on a printed circuit board having a given length to obtain an adequate matching between input and output signals.

Abstract: The invention relates to a bearing device for a spindle, for example, for a dielectric tuner (13) in a cavity filter for electromagnetic waves. The bearing device comprises at least two sprung tongues (27), each of which has a stud (28) with a partially spherical free end, where at least two of the free ends are in contact with a sliding surface (21, 44). The invention also relates to a cavity filter and a method for assembling the cavity filter.

Abstract: A high-frequency module includes a dielectric plate in which a resonator is formed and a cover for covering the dielectric plate. A hole is provided in the cover. A laser beam for laser trimming passes through the hole. The area of opening and the depth of the hole are defined so that electromagnetic waves in a usable frequency band are cut off in the hole. An electrical characteristic is measured in a state where all components including the cover are assembled, and laser trimming is performed through the hole so as to obtain a desired characteristic.

Abstract: A dielectric resonator of the present invention becomes excited in the TM mode and is provided with a dielectric material, a shielding cavity surrounding the above-described dielectric material and coupling antennas attached to the above-described shielding cavity so as to penetrate from the outside to the inside of the above-described shielding cavity, wherein it is preferable for the above-described dielectric material to be formed in a pillar form extending in the longitudinal direction, wherein it is preferable for the above-described shielding cavity to be formed so as to be hollow and so as to extend in the longitudinal direction and wherein it is preferable for the above-described dielectric material to be secured to the inside of the above-described shielding. cavity in a manner such that the longitudinal direction of the dielectric material is the same as the longitudinal direction of the above-described shielding cavity.

Abstract: A tunable resonator is provided. The resonator includes a housing having a cavity. A resonator body is disposed adjacent to a first surface within the cavity. A gap is formed between the resonator body and the first surface. The resonator is tuned by controlling the size of the gap.

Abstract: A three-dimensional periodic structure, a method of producing the same, a high frequency element, and a high frequency apparatus that can be applied to a signal transmission path or a functional element in, for example, a compact functional element in a frequency range lower than optical frequencies, such as the microwave range are provided. The three-dimensional periodic structure includes a three-dimensional periodic structure component which includes two substances having different dielectric constants periodically distributed in three-dimensional axial directions, a dielectric layer having a predetermined thickness provided at the periphery thereof, and a conductor provided on external surfaces of the dielectric layer. A third material which is different from the two substances and having predetermined dimensions embedded into the three-dimensional periodic structure component can be provided. A transmission path integrally equipped with a conductor is constructed, which is used as a pipe of a waveguide.

Abstract: The present inventions provides a dielectric ceramic comprising an oxide containing, as a metal element, at least a rare earth element (Ln), Al, M (M is Ca and/or Sr) and Ti, and at least part of the oxide of Al being present as a crystal phase of &bgr;-Al2O3 and/or &thgr;-Al2O3, thereby having a high &egr; r, high Q value and a small temperature coefficient of resonance frequency in a high frequency region.

Abstract: A TE dual-mode resonator is provided. The TE dual-mode resonator has first and second modes. The resonator includes an enclosure having a cavity with an interior surface. The resonator further includes a dielectric resonator body, having a central portion with a plurality of members extending outwardly from the central portion. The dielectric resonator body is coupled directly to the interior surface.

Abstract: A dielectric ceramic composition for radiofrequency applications has a crystalline primary component having a perovskite crystal structure, and an auxiliary component. The crystalline primary component is represented by the formula: (1−x)MeTiaO1+2a−xLn(Ma1/2Mb1/2)bO(3+3b)/2 wherein Me is at least one of Ca and Sr; Ln is a rare earth element; Ma is at least one of Mg and Zn; Mb is at least one of Sn and Zr; x represents a mole fraction of Ln(Ma1/2Mb1/2)bO(3+3b/2); and a and b represent molar ratios, wherein 0.95≦a≦1.05, 0.9≦b≦1.05, and 0.3≦x≦0.5. The auxiliary component includes B and Si. The composition can be sintered at 1,000° C. or less. An electronic component includes a ceramic element of the dielectric ceramic composition and conductors provided in the interior of the ceramic element.

Abstract: A high-frequency filter using a dielectric resonator includes an insulating substrate on which an input linear conductor and an output linear conductor are formed in parallel to each other, and a dielectric resonator which is coupled to the substrate. The dielectric resonator is arranged so that the direction of the center magnetic field of the dielectric resonator becomes approximately parallel to the substrate and becomes approximately at right angles to the linear conductors. With such an arrangement, a high-frequency filter, in which fine adjustment of a coupling factor and a resonance frequency is easy while maintaining Q of the dielectric resonator to be high, whose size can be reduced, and which can be mounted inexpensively is provided.

Abstract: The invention relates to a dielectric double-mode resonator of a radio-frequency filter that comprises a block structure comprising at least two resonator structures having at least one resonance mode each. In addition, said block structure comprises a cavity wall that limits a cavity at least partly inside the block structure, the cavity affecting the resonance modes of the at least two resonator structures. The block structure comprises a first block and a second block set against each other and each comprising at least part of the at least two resonator structures and at least part of the cavity wall limiting the cavity.

Abstract: A dual-mode resonator including a conductive cavity that houses a conductive bar and a dielectric core through which the conductive bar is inserted duplexes and couples a TEM mode generated by the cavity and the conductive bar, and a TM mode generated by the cavity and the dielectric core. A TEM single-mode resonator is formed of a cavity body and a conductive bar. The dual-mode resonator and the TEM single-mode resonator form a filter apparatus.

Abstract: A dielectric resonator device includes a dielectric plate. An electrode is provided on each of both principal surfaces of the dielectric plate and a plurality of pairs of mutually-opposing electrode openings are formed in the electrodes. Accordingly, the dielectric resonator device functions as a three-stage resonator. Strip lines serving as input/output probes are provided on the upper surface of an input/output substrate. Also, a ground electrode having electrode openings are formed thereon. By providing the dielectric resonator device and an upper substrate on the upper surface of the input/output substrate, a dielectric filter is formed.

Abstract: The dielectric loaded cavity for high frequency filters consists of a metal container housing a dielectric block held in position by supporting plates, that also sustains coupling and tuning elements. This invention provides broadband filters, small in size and with low losses. Its high symmetry structure considerably reduces the energising of spurious modes and furthermore facilitates the design using automatic calculation procedures, on the basis of accurate electromagnetic models.

Abstract: A configuration for coupling a dielectric resonator to a microstrip transmission line that maintains a relatively high Q value of the dielectric resonator. The dielectric resonator-to-microstrip transmission line coupling configuration includes a dielectric resonator, a metal wall, and a microstrip conductor mounted on a dielectric substrate surface such that the dielectric resonator is near the microstrip conductor. The dielectric resonator is configured to resonate in an intrinsic non-radiating hybrid electromagnetic mode, and the metal wall is configured as a mirror for conceptually forming an image of the resonating dielectric resonator. When an electromagnetic wave is transmitted on the microstrip transmission line, the dielectric resonator is excited to resonate in the hybrid electromagnetic mode, thereby allowing electromagnetic field coupling between the microstrip transmission line and the dielectric resonator, while maintaining a high Q value of the dielectric resonator.

Abstract: For fixing a dielectric insert in a waveguide, clamping bodies are provided which contact the dielectric insert on its outer periphery only tangentially. The dielectric insert is fixed in a wave propagation direction by a supporting element. In a further embodiment, the dielectric insert is rigidly mounted on the supporting element. As a result thermal stresses can be absorbed.

Abstract: A voltage controlled oscillator includes an active element having a first connection point for connection to a voltage source and an output connection point. A tunable resonator including a first voltage tunable dielectric device is connected to an input of the active element. A first circuit branch is also connected to the active element. The first circuit branch can include a second voltage tunable dielectric device. A tuning voltage controller supplies a control voltage to the first and second voltage tunable dielectric devices to control the frequency of an oscillating voltage at the output connection point. In a reflect type voltage controlled oscillator, the first circuit branch is a bypass circuit. In a transmission type voltage controlled oscillator, the first circuit branch includes a phase shifter and is connected between the active element output connection point and the tunable resonator.

Abstract: High performance microwave filter with monomode resonators, said filter having a resonant frequency that corresponds to an electromagnetic resonance mode of an hybrid electromagnetic family comprising electric and magnetic field patterns. The filter is characterised in that it is capable of producing perturbation in a respective electric field (a2; b2) of two of said adjacent resonators, giving rise to a coupling of relatively high magnitude between the unperturbed electric fields (a1; b1).

Abstract: A resonator for rf frequencies, especially microwave, in telecommunications systems, with an extremely stable resonant frequency over a desired operating temperature range, of predetermined width (Y) and thickness (X) and having a predetermined length (Z) in the direction of propagation for achieving a desired resonance, comprises a dielectric substrate of rutile, and first and second temperature compensating layers of sapphire on two opposite faces of the substrate and extending along the length of the substrate, these sapphire layers having a predetermined thickness, and first and second superconducting layers formed on the outer surfaces of the temperature compensating layers.

Abstract: A dielectric filter in which a desirable amount of coupling is obtainable, and the positions of an input coupling unit and an output coupling unit can be easily arranged. The dielectric filter includes a shield case, a dielectric resonator disposed inside the shield case, a supporting base for supporting the dielectric resonator, the input coupling unit, and the output coupling unit. Both the input coupling unit and the output coupling unit are coupled to the dielectric resonator. The output coupling unit is a probe with an open-circuited end, extending on a side where the supporting base of the dielectric resonator is disposed.

Abstract: The dielectric resonance device according to the present invention is constructed such that there are provided a column-shaped dielectric resonator and a column-shaped pedestal bonded to the undersurface of the dielectric resonator with the adhesive, for supporting the dielectric resonator, that on the joint surface between the pedestal and the dielectric resonator, there is provided an adhesive collecting recess so as not to reach a side of the pedestal, and that the joint surface and the undersurface of the dielectric resonator are bonded to each other with the adhesive. Therefore, the recess serves as a place for collecting the adhesive so that the adhesive which is squeezed out from between the joint surface and the undersurface of the dielectric resonator can be eliminated, making it possible to provide a dielectric resonance device with stabilized electric performance.

Abstract: The present invention is directed to a dielectric ceramic composition exhibiting a high unloaded quality factor and a small variation thereof. The dielectric ceramic composition of the invention containing Ba, Zn, and Ta, contains 100 parts by weight of a predominant component represented by xBaO—yZnO—(½)zTa2O5 (x, y, and z represent compositional proportions by mol and satisfy x+y+z=1), wherein x, y, and z fall within a quadrilateral region formed by connecting points A (x=0.503, y=0.152, z=0.345), B (x=0.497, y=0.158, z=0.345), C (x=0.503, y=0.162, z=0.335), and D (x=0.497, y=0.168, z=0.335) (sides AB, BD, DC, and CA being included) as shown in FIG. 1; 0.2-1.6 parts by weight K as reduced to K2O; and 0.7-8 parts by weight Ta as reduced to Ta2O5, wherein the ratio by weight of K to Ta falls within the range of 0.185-0.4.

Abstract: The present invention incorporates triple-mode, mono-block resonators that are smaller and less costly. The size reduction has two sources. First, the triple-mode mono-block resonator has three resonators in one block. This provides a 3-fold reduction in size compared to filters currently used which disclose one resonator per block. Secondly, the resonators are not air-filled coaxial resonators as in the standard combline construction, but are dielectric-filled blocks. The coupling between modes is accomplished by the corner cuts. One oriented along the Y axis and one oriented along the Z axis. In addition, a third corner cut along the X axis can be used. Corner cuts are used to couple a mode oriented in one direction to a mode oriented in a second mutually orthogonal direction. Each coupling represents one pole in the filter's response. Therefore, the triple-mode mono-block discussed above represents the equivalent of three poles or three electrical resonators.

Abstract: A delay filter uses the dielectric mono-block triple-mode resonator and unique inter-resonator coupling structure, having smaller volume and higher power handling capacity. The triple-mode mono-block resonator has three resonators in one block. An input/output probe is connected to each metal plated dielectric block to transmit microwave signals. Corner cuts couple a mode oriented in one direction to a mode oriented in a second, mutually orthogonal direction. An aperture between two blocks couples all six resonant modes, and generates two inductive couplings by magnetic fields between two modes, and one capacitive coupling by electric fields. The input/output probes, coupling corner cuts and aperture are aligned such that all six resonators are coupled in the desired value and sign, so constant delay on the transmitted signal within certain bandwidth can be achieved. By connecting the input and output probes to the base printed circuit board, the delay filter is surface mountable.

Abstract: The dimensions of a resonator filter comprising at least one puck (12, 14) in a metal cavity (16) are calculated by deriving the diameter c and thickness j of the puck, the spacing of the puck from the cavity walls by a mode-matching technique, then optimized by applying electromagnetic simulation of a full filter response. Other dimensions of the puck may also be optimized. If two or more pucks are present in the cavity, the inter-puck spacing is also optimized.

Abstract: A dielectric filter, a composite dielectric filter, a dielectric duplexer, a dielectric diplexer, and a communication apparatus, in which isolation between adjacent dielectric filters can be obtained, and deterioration of filter characteristics can thereby be prevented. A plurality of dielectric resonators formed by disposing dielectric cores in cavities, and coupling loops for coupling to predetermined resonance modes of the dielectric resonators, are combined to form a dielectric filter. The dielectric resonators and the coupling loops are arranged in such a manner that when the dielectric resonators of the dielectric filters are close to each other, the directions of the coupling portions of the adjacent coupling loops are substantially vertical to each other.

Abstract: The invention concerns a tunable cavity resonator that comprises a resonator body (2, 3, 4) defining a cavity (5), a tuning plate (28) whose position with respect to the resonator body (2, 3, 4) is modifiable and which influences the resonance frequency (&ohgr;R) of the cavity resonator, and an adjustment device (22, 26) for mechanically changing the position of the tuning plate (28), which is characterized in that a conversion ratio mechanism (18, 20) couples the adjustment device (22, 26) to the tuning plate (28) in terms of movement and converts a linear excursion (&Dgr;x1) generated by the adjustment device (22, 26), at a predefined ratio (U), into a reduced linear excursion (&Dgr;x2) that acts on the tuning plate (28), the conversion ratio mechanism (18, 20) comprising a first spring element (20) whose end toward the adjustment device is deflectable with the linear excursion (&Dgr;x1) generated by the adjustment device (22, 26), and a second spring element (18) which impinges with an opposing force on th

Abstract: In a cavity body, a conductor rod is provided with least one end thereof being electrically connected to the cavity. A dielectric core is disposed in the cavity and the conductor rod extends through a hole in the dielectric core. With this structure, the cavity and the conductor rod constitute a resonator which operates in the quasi-TEM mode of a re-entrant cylindrical cavity resonator. The cavity and the dielectric core constitute a resonator which operates in the quasi-TM mode.

Abstract: A high frequency ceramic compact includes Al, Ti and Mn as metallic elements and contains substantially no Al2TiO5 phase as determined by X-ray diffraction analysis and is obtained by firing at about 1310° C. or lower. A preferred high frequency ceramic compact is represented by the following formula and has a Q-value at 10 GHz of 10,000 or more: (100−x−y)AlO3/2−xTiO2−yMnO, wherein x and y are % by mole and x and y satisfy the following conditions: 3.0≦x≦9.0; and 0.1≦y≦1.0. These high frequency ceramic compacts have a relative dielectric constant of 20 or less, a Q-value at 10 GHz of 10,000 or more, and can optionally control the temperature coefficient of resonant frequency around 0 ppm/° C.

Abstract: A dielectric resonator is provided having a cavity, a dielectric half disk resonator structure structure, and a support for the half disk resonator structure. The support isolates the dielectric half disk resonator structure from walls of the cavity. A straight edge wall of the dielectric half disk resonator structure couples to a dielectric/air interface within the cavity and forms an approximate magnetic wall. The approximate magnetic wall images the electric field perpendicular to the straight edge wall and supports a single-mode electric field within the half disk resonator structure. Multiple half disk resonator structures may be oriented within the cavity to support other, orthogonal electric fields. Multiple cavities may be coupled to each other through irises formed on the cavity walls.

Abstract: The present invention provides a dielectric resonator having increased reliability with respect to thermal cycle fatigue of a joint between a conductive cavity and a dielectric core disposed in the cavity without an increase in material cost and processing cost, a filter and duplexer each using the dielectric resonator, and a communication device including these devices. The dielectric resonator has a structure in which the dielectric core is provided in the cavity through earth plates. Each of the earth plates has slits provided at positions in contact with the four corners of each of two opposing side faces of the dielectric core. Of the four sides of each of the earth plates, the two sides provided with spring portions are preferably inclined so that the distance between the two sides decreases toward the bottom of the cavity, and concave portions are formed in the inner surface of the cavity corresponding to the two inclined sides.

Abstract: A dielectric resonator oscillator (DRO) (200, FIG. 2; 600, FIG. 6; 900, FIG. 9) includes a dielectric resonator (202, 602, 902) that is held in a fixed position with respect to the housing lid (206, 606, 906). In one embodiment, the resonator is attached to the housing lid using one or more support legs (208). In another embodiment, the resonator is attached to the housing lid using a ring structure (608). In still another embodiment, the resonator is attached to the lid and housing (904) using a lid tuner (914) and lid pedestal (908), and a housing tuner (915) and housing pedestal (909). Resonator positioning within the DRO cavity (222, 622, 922) is simplified by accurately aligning and attaching the support structure to the resonator.

Abstract: Dielectric tube loaded metal cavity resonators and filters having a dielectric tube resonator extending substantially the full height of the metallic cavity are disclosed herein. The resonators and filters achieve low insertion loss in a size substantially smaller than conventional dielectric loaded resonators for equivalent quality factors. The dielectric tube resonators may be used with coaxial resonators to provide mixed resonator filter constructions.

Abstract: A HE0&ggr;&dgr; mode dielectric resonator (12) includes a cylindrical dielectric disk (32) having top and bottom ends (20, 22) spaced apart by a closed curve wall (24). The dielectric disk (32) has a dielectric constant greater than 40. An axially aligned hole (36) is formed through the disk (32) between the top and bottom ends (20, 22). A conductive wall (34) is formed at the closed curved wall (24) but not the top and bottom ends (20, 22). The hole (36) has a preferred diameter less than 0.2 times the diameter of the disk. A tuning plug (30) is formed from a material having a dielectric constant less than 0.5 times the dielectric constant of the dielectric disk (32) and an unloaded quality factor greater than 2.0 times the unloaded quality factor of the dielectric disk (32). The tuning plug is inserted to a desired depth within the hole (36) of the dielectric disk (32).

Abstract: A dielectric filter comprises a dielectric substrate having two opposing main surfaces on which electrodes are formed. Electrodeless portions are formed in the electrodes on the two main surfaces. Conductors are arranged a fixed distance away from the dielectric substrate. The electrodes have projections and/or recesses formed in the boundary region between the electrodeless portion and the electrode.

Abstract: A TE dual-mode resonator is provided. The TE dual-mode resonator has first and second modes. The resonator includes an enclosure having a cavity with an interior surface. The resonator further includes a dielectric resonator body, having a central portion with a plurality of members extending outwardly from the central portion. The dielectric resonator body is coupled directly to the interior surface.

Abstract: A dielectric resonance device includes a cavity body, a support base disposed inside the cavity body, and a dielectric core supported by the support base. A stepped portion is provided inside the cavity body such that a gap between the outer circumferential surface of the dielectric core and the inner wall surface of the cavity body and a gap between the peripheral portion of the support-base attachment surface of the dielectric core and the stepped portion change in opposite directions with temperature variation. Thus, variation with temperature in the resonance frequency of a TM01&dgr; mode is suppressed.

Abstract: A dielectric loaded cavity filter having a housing and a cover and defining at least two adjacent cavities having respective dielectric resonators mounted therein and separated by a transverse partition defining a coupling window in the housing. In one form, the coupling window has two spaced opposing sidewalls confronting each other, and vertically offset shoulders intermediate their length. A conductive coupling strip is secured to the shoulder of one sidewall and extends across the coupling window and over the shoulder of the other sidewall. A tuning screw is secured by threading to the housing and has an outer free end accessible from the exterior of the filter, and an internal end disposed adjacent the coupling strip, whereby when the tuning screw is rotated, the internal end of the screw moves toward and away from the coupling strip in a direction perpendicular to the cover for tuning without requiring access to the coupling strip.

Abstract: A multimode dielectric resonator apparatus is configured such that a TM mode and a TE mode are transformed into multiplex modes, coupling between individual resonant modes can be easily made, and a large number of sequentially coupled stages can be obtained with a single dielectric core. In the multimode dielectric resonator apparatus, a dielectric core is configured of a plate-like TM-mode dielectric core portion and a TE-mode dielectric core portion protruding therefrom in the vertical direction, for example in a spherical shape. Five modes, namely a TMx mode, a TMy mode, a TEx mode, a TEy mode, and a TEz mode are used as multiplex modes. In addition, a filter and a duplexer use the multimode dielectric resonator apparatus, and a communication apparatus uses one or both of the filter and the duplexer.

Abstract: A small in-band-flat-group-delay type dielectric filter having low-loss characteristics with a small amplitude deviation and uniform-group-delay frequency characteristics is obtained, which enables broad-band characteristics to be obtained easily. The in-band-flat-group-delay type dielectric filter includes a plurality of dielectric coaxial resonators, a coupling circuit comprising a combination of reactive elements, with which the dielectric coaxial resonators are coupled to one another, and input/output terminals connected to ends of the coupling circuit. The dielectric coaxial resonators coupled to the input/output terminals are allowed to have a different characteristic impedance from that of the inter-stage dielectric coaxial resonators.