Abstract: An electromagnetic filter assembly includes complimentary first and second blocks (1) and (2) defining two conjoined sections (10), (11) of an electromagnetic waveguide duct. A shim-like electromagnetic filter element (3) is held between the blocks and contains a series of holes (14) defining bridges (15) which traverse the waveguide duct to form poles of an electromagnetic filter. The filter element includes integral tuning projections (20) which extend into waveguide duct between the bridges. By adjusting the position of the filter element (3) between the blocks (1), (2) it is possible to vary the extent to which the tuning projections (20) project into the waveguide duct. The arrangement thus facilitates the repeated, continuous adjustment and variation of the electrical characteristics of devices such as filters, diplexers and multiplexers.

Abstract: Disclosed is a waveguide-type dielectric filter, which comprises a dielectric block, a plurality of resonators formed in the dielectric block, and a coupling portion for adjusting the coupling between the adjacent resonators. The dielectric block includes a pair of dielectric substrates which are divided in the arranging direction of the resonators and joined together through joint surfaces thereof, and a slot formed between the joint surfaces. The slot defines a through-hole severing as the coupling portion between the adjacent resonators. The slot may be formed in each of the joint surfaces or may be formed in only one of the joint surfaces. The above dielectric filter may include input and output sections, and a conductive film may be formed between the joint surfaces to provide a coupling portion of the input or output section. The present invention can provide a waveguide-type dielectric filter capable of being readily produced without causing any problem of mechanical strength.

Abstract: Provided are a filter and a method of arranging resonators, which enable forming an attenuation pole and thus achieving excellent frequency characteristics. The filter includes a plurality of resonators. An electromagnetic wave enters through an input end into one of the resonators and exits through an output end from another resonator. The resonators are arranged so that two propagation paths are formed between the input end of one resonator and the output end of another resonator. Forming a plurality of propagation paths allows producing the attenuation pole.

Abstract: A filtering system with a probe for coupling two resonators includes an iris having the probe disposed therein coupled between the two resonators. The probe has a transverse opening for receiving a tuning conductor, and the tuning conductor provides adjustable coupling between the two resonators.

Abstract: The invention relates to a quadruple mode microwave filter having coupled cavities with a plurality of transmission zeros, said filter comprising at least one rectangular parallelepiped-shaped quadruple mode cavity, at least two rectangular irises, and two input/output waveguides. Tuning and coupling of the filter are obtained exclusively by the dimensions and mutual disposition of the at least one resonant cavity and the irises, without any screw or other tuning mechanism. All the faces of the cavities and the irises are either parallel or perpendicular to each other. In a preferred embodiment the irises are offcentered along the two transverse axes. According to one advantageous feature, the input mode and the output mode are the same, preferably the TE 10 fundamental mode.

Abstract: An E-plane filter comprises a housing having a waveguide filter channel and a septum defining a plurality of couplers spaced apart along the length of the filter channel, thereby forming a resonator cavity between each adjacent coupler. The portion of the filter channel which accommodates the couplers and each resonator cavity is curved or otherwise changes direction in a plane transverse to the channel walls.

Abstract: A plate has an iris defined by an aperture, and a rod extending radially outward from the iris through the plate. The rod is radially adjustable and a sleeve is disposed on the rod, for tuning the plate by slidably adjusting the rod radially.

Abstract: A highly compact bandpass filter that has excellent mechanical strength is disclosed. A bandpass filter according to the present invention employs a dielectric block of substantially rectangular prismatic shape constituted of a first portion lying between a first cross-section of the dielectric block and a second cross-section of the dielectric block substantially parallel to the first cross-section and second and third portions divided by the first portion and metal plates formed on surfaces of the dielectric block. The first portion of the dielectric block and the metal plates formed thereon are enabled to act as an evanescent waveguide. The second portion of the dielectric block and the metal plates formed thereon are enabled to act as a first resonator. The third portion of the dielectric block and the metal plates formed thereon are enabled to act as a second resonator. The metal plates include an inductive stub formed on the surface of the first portion of the dielectric block.

Abstract: The invention relates to a quadruple mode microwave filter having coupled cavities with a plurality of transmission zeros, said filter comprising at least one rectangular parallelepiped-shaped quadruple mode cavity, at least two rectangular irises, and two input/output waveguides. Tuning and coupling of the filter are obtained exclusively by the dimensions and mutual disposition of the at least one resonant cavity and the irises, without any screw or other tuning mechanism. All the faces of the cavities and the irises are either parallel or perpendicular to each other. In a preferred embodiment the irises are offcentered along the two transverse axes. According to one advantageous feature, the input mode and the output mode are the same, preferably the TE 10 fundamental mode.

Abstract: The invention provides a particularly compact waveguide-type filter that can be easily adapted to a microstrip circuit. The waveguide filter comprises at least three mutually coupled resonant cavities 14 to 19. The filter is coupled to a microstrip circuit placed on a substrate 10. At least one cavity 14, 15, 18 and 19 lies on one side of the substrate 10 and at least one other cavity 16, 17 lies on the other side of the substrate 10. The cavities distributed on either side of the substrate have the effect of greatly reducing the size of the filter. The invention also relates to an outdoor transmission unit that includes the said filter.

Abstract: A rectangular penetration hole is formed opening in the opposite two main surfaces of a first dielectric substrate. Conductors for grounding are respectively formed on the main surfaces, to cover the openings of the penetration hole. A conductor layer is formed on opposite inner walls in the penetration hole of the dielectric substrate. A waveguide is structured by a space surrounded by the conductors and the conductor layers. The waveguide is magnetically coupled with an input/output line on a second dielectric substrate through a coupling slot. Because a waveguide has walls made continuous in the dielectric substrate, a low-loss waveguide can be realized. Hence, a high-performance radio frequency module can be realized.

Abstract: An inner conductor comprising high impedance portions and low impedance portions alternately connected to each other is disposed in the center of an outer conductor having a substantially square cross-section. Two holes are formed in one side of the outer conductor so as to extend through the wall of the outer conductor. A substantially &pgr;-shaped coupling line comprising a main line portion and probe-connecting portions is formed on the surface of a dielectric substrate. Probes made of conductor rods are connected at the ends, respectively. A resistor is provided at one end of the main line of the coupling line. The other end of the main line functions as an output terminal, and can be connected to an external circuit. The probes are inserted through the holes. The dielectric substrate is disposed inside of the outer conductor at predetermined positions.

Abstract: Provided are a filter and a method of arranging resonators, which enable forming an attenuation pole and thus achieving excellent frequency characteristics. The filter includes a plurality of resonators. An electromagnetic wave enters through an input end into one of the resonators and exits through an output end from another resonator. The resonators are arranged so that two propagation paths are formed between the input end of one resonator and the output end of another resonator. Forming a plurality of propagation paths allows producing the attenuation pole.

Abstract: Disclosed is a waveguide-type dielectric filter, which comprises a dielectric block, a plurality of resonators formed in the dielectric block, and a coupling portion for adjusting the coupling between the adjacent resonators. The dielectric block includes a pair of dielectric substrates which are divided in the arranging direction of the resonators and joined together through joint surfaces thereof, and a slot formed between the joint surfaces. The slot defines a through-hole severing as the coupling portion between the adjacent resonators. The slot may be formed in each of the joint surfaces or may be formed in only one of the joint surfaces. The above dielectric filter may include input and output sections, and a conductive film may be formed between the joint surfaces to provide a coupling portion of the input or output section. The present invention can provide a waveguide-type dielectric filter capable of being readily produced without causing any problem of mechanical strength.

Abstract: A multi-mode resonator device can be reduced in size even while increasing the number of resonators while including either a semi-coaxial resonator or a coaxial resonator. Coupling between a TEM mode as a resonance mode of the semi-coaxial resonator and a TM mode as another resonance mode can be facilitated, which enables coupling between the resonators at a predetermined coupling strength. Inside a cavity with a cover, a conductive rod and a dielectric core are disposed so as to substantially equalize a quasi-TEM-mode resonant frequency generated by the cavity and the conductive rod and a quasi-TM-mode resonant frequency generated by the cavity and the dielectric core. A coupling adjusting block is arranged at a place where the magnetic field of one of two coupling modes generated by the quasi-TEM and quasi-TM modes is strong and that of the other mode is weak. The invention also provides a filter, duplexer, and a communication apparatus using the resonator device.

Abstract: The waveguide polarizer is a device for microwave antenna systems consisting of a waveguide section, with circular cross-section, being equipped with two terminal flanges for connection to other circular guides. A certain number of elliptical irises are arranged inside at regular intervals, resting on parallel planes and all oriented in the same way, i.e. with their longer axes all belonging to the same axial plane.

Abstract: A dielectric resonator filter comprises dielectric resonators, an enclosure having a main body, a lid, and partition walls, interstage-coupling tuning windows, interstage-coupling tuning bolts, input/output terminals, and input/output coupling probes. Resonance-frequency tuning members each composed of a conductor plate and a bolt coupled integrally thereto are attached to the enclosure lid. Undesired-mode suppressing means such as rings attached to the bolts of the resonance-frequency tuning members or bolts attached to the conductor plates or to the enclosure lid are disposed in an undesired-mode excitation space, whereby the occurrence of a disturbed characteristic in the pass band (or stop band) is suppressed.

Abstract: A filter element comprising a conductive element mounted in a conductive housing, the conductive element and conductive housing arranged such that the conductive element is electrically coupled to the conductive housing at one end of the element and capacitively coupled to the conductive housing at the opposite end of the element with a solid dielectric element disposed around a length of the conductive element.

Abstract: The requirements of wider bandwidths for communication systems and the resultant use of the millimetre wave region are discussed. The tolerances of filter components for use in the millimetre wave region have required costly manufacturing. E-plane filters (400), a tuning element (450) for such a filter (400), and methods of making and tuning such a filter (400) are disclosed. In particular, the manufacturing (and tuning) technique allows filters (400) of this type to be used at higher frequencies without the need for using higher precision, high cost manufacturing techniques. The filter (400) has at least two waveguide members (410A, 410B) and at least one septum (430) disposed in a waveguide cavity (420) formed by the assembled waveguide members (410A, 410B). The characteristics of the filter (400) are tested.

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: A compact multiple VSWR element filter in which one or more of the VSWR filter elements is a waveguide bend or a waveguide media transition. Methods are also disclosed.

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: An E-plane waveguide is provided comprising a housing having opposed walls defining a waveguide channel. The waveguide includes at least two elements spaced apart in a direction along the waveguide channel and disposed between and spaced from the opposed walls, and which define a resonant cavity therebetween with the waveguide channel. At least one of the walls has first and second protrusions which are spaced apart in a direction along the waveguide channel and protrude into the waveguide channel. The spacing between the protrusions is less than half a wavelength of the resonant frequency of the resonant cavity.

Abstract: A test system having a shielded enclosure and common air interface for testing the transmit and receive functionality of wireless communication devices such as mobile phones. A test system according to the present invention provides improved fault coverage by permitting robust testing of the entire signal path of a wireless device, including the antenna structure. In one embodiment of the invention, an RF-shielded enclosure having a test chamber is provided. The structure of the shielded enclosure blocks ambient RF energy from entering the test chamber and interfering with testing operations. The shielded enclosure may be lined with an RF absorbing material to improve test repeatability. A novel test antenna structure is disposed in the test chamber for wirelessly communicating test signals to a device under test.

Abstract: Waveguide filters for filters operating at millimeter wavelengths which require high accuracy. The filter includes a plurality of discs held in the cylinder of a support. Each disc has a recess defining cavity size. The various parts forming the filter are simplified thereby making it possible to reduce production costs while providing good accuracy.

Abstract: An injector device for microwave filter units made up of channel filters (1″, 1″′) provided with cavities housing dielectric resonators. Each filter has an input cavity which receives a signal transmitted by a coaxial cable terminating at a connector (15″, 15″′) mounted through a wall closing the cavity at an input end of the filter. The injector device of a filter acts electrically on a dielectric resonator accommodated in the input cavity via a probe (16) consisting of a L-shaped rod having a first portion connected to the core of the coaxial cable to extend it into the cavity and a second portion acting on a dielectric element (13) of the resonator via electrical coupling means. The invention also relates to filter units equipped with such injector devices.

Abstract: Disclosed is a metal window filter assembly, of a millimeter wave band, using an NRD guide. The filter assembly comprises a filter housing including parallel conductive plates and a filter for filtering a certain frequency band of an electromagnetic wave traveling therethrough. The filter includes a plurality of polygonal metal windows and a single body type dielectric line made from a non-radiative dielectric. A plurality of polygonal inserting grooves spaced by the predetermined distance are formed respectively on both surfaces of the dielectric line making contact with the parallel conductive plates. The metal windows are inserted in the inserting grooves one to one to form multi-staged dielectric resonators cascaded as a single body. The filter has a filtering function selectively passing the certain frequency band determined by an impedance coupling relationship that the multi-staged dielectric resonators have with respect to the electromagnetic wave.

Abstract: Electrodes are formed on both surfaces of a dielectric plate. Openings are formed in the electrodes such that pairs of openings face each other through the dielectric plate. Each pair of electrode openings defines a resonator. The resonators positioned at the ends of the dielectric plate are directly coupled to a waveguide formed by a package base and a package cover.

Abstract: A filter that produces a multiple passband response as a single device. The multiple passband filter has a plurality of poles concentrated in a desired passband of the filter. A plurality of zeroes are located outside of the desired passband to form passband edges. One or more zeroes are located in a central portion of the passband to form multiple passbands within the passband edges.

Abstract: A rectangular penetration hole is formed opening in the opposite two main surfaces of a first dielectric substrate. Conductors for grounding are respectively formed on the main surfaces, to cover the openings of the penetration hole. A conductor layer is formed on opposite inner walls in the penetration hole of the dielectric substrate. A waveguide is structured by a space surrounded by the conductors and the conductor layers. The waveguide is magnetically coupled with an input/output line on a second dielectric substrate through a coupling slot. Because a waveguide has walls made continuous in the dielectric substrate, a low-loss waveguide can be realized. Hence, a high-performance radio frequency module can be realized.

Abstract: A highly compact band pass filter that reliably achieves desired characteristic is disclosed. A band pass filter according to the present invention employs first and second disk resonators having exciting electrodes formed on one side surface thereof, an evanescent waveguide interposed between the first and second disk resonators, and a capacitive stub formed on other side surfaces of the first and second disk resonators. The capacitive stub reduces the size of the band pass filter because a resonant frequency of the disk resonators is lowered by the capacitive stub. Further, the capacitive stub enhances the mechanical strength of the band pass filter because a coupling constant k between the disk resonators is lowered by the capacitive stub.

Abstract: A cross-coupled bandpass filter for a microwave electromagnetic signal which utilizes a housing which has formed therein a plurality of sequentially located resonator cavities with these cavities being interconnected by in-line couplers. A resonator is mounted within each cavity. A cross-coupler is disposed between a pair of the cavities that are not sequentially located. The cross-coupler takes the form of a printed circuit board upon which are mounted at least one manually movable screw access to which is permitted exteriorly of the cavities.

Abstract: A filter includes an electromagnetic wave supporting structure having a cavity defined by an encircling sidewall, and microwave feeds coupled to the cavity for inputting and for outputting electromagnetic power to and from the wave supporting structure. At least a portion of an interior surface of the sidewall has a succession of corrugations. Successive ones of the corrugations are spaced apart by a distance less than approximately 0.2 wavelength of the electromagnetic wave, and each of the corrugations has a height greater than the spacing distance but less than approximately 0.5 wavelength of the electromagnetic wave. The geometry of the corrugated sidewall reduces interaction between the electromagnetic wave and the sidewall to inhibit dissipation of power of the electromagnetic wave within the sidewall.

Abstract: The invention provides a dual-mode microwave filter, comprising a rectangular resonator of length l, height b, and width a operating in two distinct modes (m, 0, n) and (p, 0, q) from a single family of modes and presenting the same direction as the E field, and wherein coupling and mode excitation discontinuities are inductive and in the same direction.

Abstract: A bandpass filter makes use of at least one waveguide cavity that is thermally compensated to minimize drift of a resonant frequency of the cavity with thermal expansion of cavity components. The compensation relies on deformation of the shape of at least one cavity surface in response to thermally induced dimensional changes of the cavity. A control rod is used to limit the movement of a point on the deformed surface, while the rest of the surface moves with the thermal expansion. The control rod is made of a material having a coefficient of thermal expansion that is significantly different than that of other filter components. The rod may also be arranged to span more thermally expandable material than defines the filter such that, as the filter expands, the point of deflection is moved toward the interior of the filter beyond its original position.

Abstract: The invention relates to a method for producing a microwave filter (700), comprising making at least one through-cutout (750) in a first electrically conductive plate (740) shaped as a rectangle, with a short side and a long side, inserting the first plate (740) between a second (710) and a third (730) electrically conductive plate (710), the first plate being arranged parallel to the second and the third plate, making electrical connections (794, 795) between said three plates for interconnecting those edge surfaces on the plates which coincide with the direction of propagation of the electrical signals, as a result of which a space comprising one or more cavities is formed. The first plate (740) is arranged so that the extent of its short side coincides with the E-field of the microwave signals when they propagate in the filter (700), and the extent of its long side coincides with the direction of propagation of the electrical signals.

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: In a dual-mode bandpass filter, a metal film is partially formed on one surface of a dielectric substrate or at a certain vertical level within the dielectric substrate, first and second input/output coupling circuits are coupled to the metal film, at least one capacitor is loaded to the metal film so that when an input signal is applied from either input/output coupling circuit, two resonant modes generated in the metal film are coupled. The capacitor preferably includes via-hole electrodes opposing the metal film.

Abstract: Disclosed is a metal window filter assembly, of a millimeter wave band, using an NRD guide. The filter assembly comprises a filter housing including parallel conductive plates and a filter for filtering a certain frequency band of an electromagnetic wave traveling therethrough. The filter includes a plurality of polygonal metal windows and a single body type dielectric line made from a non-radiative dielectric. A plurality of polygonal inserting grooves spaced by the predetermined distance are formed respectively on both surfaces of the dielectric line making contact with the parallel conductive plates. The metal windows are inserted in the inserting grooves one to one to form multi-staged dielectric resonators cascaded as a single body. The filter has a filtering function selectively passing the certain frequency band determined by an impedance coupling relationship that the multi-staged dielectric resonators have with respect to the electromagnetic wave.

Abstract: The waveguide group branching filter according to the present invention is formed by boring out of two metal blocks constituent circuits including a circular-to-square waveguide multistage transformer 1, the branch waveguide polarizer/branching filter 4, a rectangular waveguide multistage transform 9, the rectangular waveguide H-plane T-branch circuit 10, and waveguide band-pass filters 8, 14 and 18; radio waves V1 and H1, which have their polarization planes vertical and horizontal, respectively, to the branching plane of the branch waveguide polarizer/branching filter 4 in a certain frequency band f1, and a radio wave V2 of the same polarization plane as that of the radio wave V1 in a frequency band f2 higher than the frequency band f1 are incident to an input port P1, and the radio wave V1 is emitted from an output port P2, the radio wave H1 from an output port P3 and the radio wave V2 from an output port P4.

Abstract: Disclosed is a metal post filter assembly, of a millimeter wave band, using an NRD guide. A filter to which an electromagnetic wave travels is disposed in a filter housing which includes parallel conductive plates facing each other. The filter forms a plurality of inserting holes, by segmenting them into multi-stages, along the length direction of side surface of a dielectric line and parallel to the parallel conductive plates. The filter has a structure that multi-staged dielectric resonators are formed in a single body by inserting metal posts which provide discontinuous surfaces which cause a reflection with respect to the electromagnetic wave in each of the inserting holes. Each impedance of the multi-staged dielectric resonators has an impedance coupling relationship that the impedance becomes gradually and symmetrically smaller to both end stages.

Abstract: Disclosed is a metal post filter assembly, of a millimeter wave band, using an NRD guide. A filter to which an electromagnetic wave travels is disposed in a filter housing which includes parallel conductive plates facing each other. The filter forms a plurality of inserting holes, by segmenting them into multi-stages, along the length direction of side surface of a dielectric line and parallel to the parallel conductive plates. The filter has a structure that multi-staged dielectric resonators are formed in a single body by inserting metal posts which provide discontinuous surfaces which cause a reflection with respect to the electromagnetic wave in each of the inserting holes. Each impedance of the multi-staged dielectric resonators has an impedance coupling relationship that the impedance becomes gradually and symmetrically smaller to both end stages.

Abstract: A filter that produces a multiple passband response as a single device. The multiple passband filter has a plurality of poles concentrated in a desired passband of the filter. A plurality of zeroes are located outside of the desired passband to form passband edges. One or more zeroes are located in a central portion of the passband to form multiple passbands within the passband edges.

Abstract: A composite resonator (10) consisting of a conducting metal (14) and a dielectric material (12) is used to provide resonant frequencies lower than can be obtained using the same volume of dielectric alone and with higher unloaded Q than can be obtained using the same volume of metal imbedded into a cavity and used as a resonator. This significantly reduces the cost and size of the resonator (10) without degrading its performance. An inexpensive metal (14), such as aluminum, can be substituted for more than half of the dielectric (12) and stille form a resonator (10) with substantially equivalent resonant properties. The operative embodiments of the resonator invention (1) cover composites with doughnut-shaped, i.e., cylindrical, configurations, with the “doughnut” either metal (14) or dielectric (12), and the “hole” either dielectric (314) or metal (312), respectively.

Abstract: An equalizer that couples a dual-mode dielectric resonator to a planar transmission line, creating an all-pass network. Coupling is achieved using circular polarization of the electromagnetic field in the dielectric resonator. The all-pass, non-reciprocal network is realized by the use of circular polarized energy and an offset cross shaped, through transmission line.

Abstract: A cavity filter assembly is provided with at least one structural cavity wall comprising a circuit board. The circuit board may also contain other circuits and circuit elements such as trim capacitors, inductors, low noise amplifier circuits and power amplifiers that are part of the filter's function. Input and output coupling structures and connectors may also be provided on the circuit board. The circuit board may contain inter-stage coupling circuits, signal traces, and coupling pads/structures. Further embodiments are provided that incorporate test connectors and directional couplers on the circuit board. In yet other embodiments the filter's electrical characteristics are tunable with trim elements mounted on the circuit board, such as capacitors or inductors, in either mechanical or electrical manner. The filter's electrical characteristics may also be tunable with mechanical elements mounted through the circuit board.

Abstract: A microwave filter has a set of irises to couple cavities within the filter. A trifurcated iris comprises a central iris and a pair of peripheral irises. The peripheral irises are configured and oriented to couple a primary mode having a magnetic field in the axial direction of a filter cavity. The central iris is configured and oriented to couple a secondary mode having a magnetic field in the azimuthal direction of the filter cavity. The configuration of the trifurcated iris is further oriented to minimize the influence of higher order signals such as the TE21X mode. The peripheral iris are oriented at null points of the primary TE21X mode and the central iris is also located at a null point. An input and an output iris are configured to receive electromagnetic energy in the axial direction of the filter. The input and output irises are oriented to minimize signals in the TE21X secondary mode and any TM modes.

Abstract: An instrument is disclosed for microwave-assisted chemical processes that avoids tuning discrepancies that otherwise result based upon the materials being heated. The instrument includes a source of microwave radiation, a waveguide in communication with the source, with at least a portion of the waveguide forming a cylindrical arc, a cylindrical cavity immediately surrounded by the cylindrical arc portions of the waveguide, and at least three slotted openings in the circumference of the circular waveguide that provide microwave communication between the waveguide and the cavity.

Abstract: A tuneable E-plane waveguide filter is presented. Tuning is achieved using sliders inserted into the cavities of the insert of the waveguide filter. The sliders are inserted through gaps or notches in the insert, or through notches in the waveguide housing. The positions of the sliders is adjusted to fine-tune the frequency response of the waveguide filter, overcoming limits on narrow relative bandpasses imposed by manufacturing tolerances. When a desired frequency response is achieved, the sliders are fixed in position. Assembly and tuning is less expensive and less complex than tuneable H-plane waveguide filters.

Abstract: An adjustable coupling arrangement for aperture coupled cavity filters. According to the invention, in an electric wall (24) separating two cavities to be coupled in a bandpass filter, provide a cruciform iris (26) comprising a central aperture (27) having four slits (28,29,30, 31) extending outwardly therefrom. In each slit there is arranged a captive movable rectangular metal slug (36,37,38,39) whose position along the slit's length can be manipulated by a tool that engages the slug when the tool is introduced into a radial passageway (32,33,34 35) that connects the slit with an access hole in the filter's housing. When desired coupling parameters are achieved by manipulating each of the slugs to effectively change the electrical length of the slits, each slug is locked in position by a respective associated locking means actuated by the tool. Because a significant part of the tool is within a passageway during manipulation, the filter's characteristics are not disturbed by its presence.