Abstract: A method of treating a first chemical species in a gas using a plasma, the method including the steps of providing an array of micro-scale cavity discharge devices capable of sustaining the plasma where the first chemical species is capable of flowing proximate to the array of micro-scale cavity discharge devices, wherein the first chemical species is converted to a second chemical species within the plasma.

Abstract: A filter or multicoupler has at least one resonator which can be electronically tuned by a tuning device, has at least one tuning element such as a tuning capacitor, a switching element for selectively connecting the tuning element electronically to the resonator, and a control device for the switching element. The resonator is a coaxial quarter-wave resonator with a central component having free surface perpendicular to the central axis for mounting of tuning devices.

Abstract: A tunable, temperature compensated, thermal and mechanical stable, dielectric loaded cavity resonator and filter assembly has high unloaded Q, wide frequency tuning range and simple structure suitable for high volume production. The cavity resonator consists of a conductive housing, a substantially cylindrical ring shape dielectric body with a low loss, low thermal expansion coefficient support, a tuning mechanism and a plastic support at the opposite side of the main cylindrical dielectric body, which holds the main cylindrical dielectric body in place. The tuning mechanism further includes a substantially cylindrical dielectric tuning element positioned in or near the hole of the main cylindrical dielectric body and a self-locked or equivalent nut locked rotor with a support using the same material as that of the main cylindrical body support.

Abstract: Apparatus and method for filtering an electromagnetic signal employs the feeding of the signal via a rectangular waveguide to a plural mode cavity filter with coupling available at plural modes. The cavity has a mode-coupling structure such as a mode-coupling screw. The waveguide operates at a first mode of lower cutoff frequency and a second mode of higher cutoff frequency. The feeding is at a frequency for propagation in the first mode. The cavity radiates back into the waveguide, or into another waveguide, below the higher cutoff frequency to provide an evanescent reactive loading which reduces the required penetration of tuning screws for reduced dissipation of power in the tuning screws.

Abstract: A microwave filter cavity that exhibits spurious mode suppression. The microwave filter comprises a metal mode suppression tuning stub located in a replaceable iris plate that is used to suppress unwanted transverse magnetic (TM) modes of the filter cavity, The mode suppression stub is disposed normal to an end wall of the cavity. The mode suppression stub perturbs the E-field of transverse magnetic modes, while having negligible effect on desired transverse electric (TE) modes. The addition of the tuning stub has no effect on filter performance determined by transverse electric modes.

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: The invention relates to an arrangement of the filter or multicoupler type.

Abstract: A compact and highly controllable impedance-varying-unit, a microwave device using the same unit, and a high-frequency-heating appliance using the same unit are provided. The impedance varying unit includes a rectangular waveguide-section as a main body made of metallic material, an open end of waveguide-section working on microwave in a microwave cavity, a terminal end of waveguide-section closed by metallic material, a rotary movable body made of non-metallic material, and a driver for the movable body. A rotating angle or a position of the movable body is controlled, so that an impedance at the open end is varied and transmission status of microwave is changed, thereby variably controlling a standing wave distribution. Controlling the standing wave distribution allows an object in the cavity to be selectively heated or uniformly heated. Further, the standing wave produced in the microwave cavity is sequentially varied, so that the object can be selectively heated or uniformly heated.

Abstract: It is an object of the invention to propose a mechanical gearing for a tuner for cavity resonators, which can be realized and operated in a less expensive version and with long service life and little backlash even at very low temperatures. At the same time, there is no piezoelectric or magnetostrictive driving mechanisms or their combinations with coarse driving mechanisms. The tuner includes a multi-stage lever mechanism, for which the fulcrum and the movable connecting site are integral and are connected over a narrow cross member. The connecting sites between the stages of the multi-stage lever mechanism are constructed as a bolt-shaped part, the ends of which are firmly connected with one stage and the middle part of which is connected with the other stage.

Abstract: The present invention relates to a duplexer set up by two decoupling filters for high frequency transceivers of the temperature self-compensating type and implemented by means of a pair of mechanic bodies (2), each one of which including a plurality of resonance cavities (3). Inside of the cavity (3) of the superior body (2) of the duplexer, a corresponding adjustment disc (7) is lodged in a removable and coaxial way which is provided with a supporting stem (8) coming out of a passage hole (12) obtained on the summit of the cavity (3). The bodies (2) are bound between them, so that the cavities of one or the other turn out to be coaxially facing each other. The passage hole (12) of the filter according to the invention is threaded. Moreover at each filter at least one bush (9) is associated having one portion (11) engaged in the hole (12) and inside of which the stem (8) of the disc (7) is housed.

Abstract: An active radio frequency cavity amplifier (ARFCA) is provided having a housing defining an input cavity and an output cavity; a plurality of transistors mounted to said housing, each of the plurality of transistors having an input lead and an output lead; a first RF power coupling mechanism disposed within the housing in proximity to the input cavity for coupling RF power from a source into the input cavity to generate an RF field; a first conducting assembly having a plurality of conductors each configured to contact a respective input lead of each of the plurality of transistors for coupling the RF field in the input cavity to the input leads of the plurality of transistors; a second conducting assembly having a plurality of conductors each configured to contact a respective output lead of the plurality of transistors for coupling the amplified RF power from the output leads of the plurality of transistors to the output cavity; and a second RF power coupling mechanism disposed within the housing in proximi

Abstract: A tunable dielectric structure includes a first layer of dielectric material, a second layer of dielectric material positioned adjacent to the first layer of dielectric material, with the second layer of dielectric material having a dielectric constant that is less than the dielectric constant of the first layer of dielectric material, and electrodes for applying a controllable voltage across the first dielectric material, thereby controlling a dielectric constant of the first dielectric material, wherein at least one of the electrodes is positioned between the first and second layers of dielectric material. The dielectric materials can be formed in various shapes and assembled in various orientations with respect to each other. The tunable dielectric structure is used in various devices including coaxial cables, cavity antennas, microstrip lines, coplanar lines, and waveguides.

Abstract: A dielectric resonator of the invention includes a cavity having a first threaded hole; a dielectric block provided in the cavity; a coupling device coupled with an electromagnetic field produced in the cavity; a frequency tuning member having a screw portion which is spirally engaged with the first threaded hole of the cavity, a distance between the dielectric block and the frequency tuning member being changed by rotating the frequency tuning member, for tuning a resonance frequency of the cavity depending on the distance; and fixing means for fixing a relative positional relationship between the frequency tuning member and the cavity, wherein the fixing means prevents the frequency tuning member from rotating due to a frictional force caused between the first threaded hole of the cavity and the screw portion of the frequency tuning member, the fixing means including a lock nut having a second threaded hole which is spirally engaged with the screw portion of the frequency tuning member.

Abstract: An assembly for supporting a substrate of an integrated circuit and forming a cavity resonator with the substrate. The assembly includes a baseplate in which a cavity for the cavity resonator is integrally formed. A substrate is mounted over the cavity resonator in the baseplate and an excitation coupling extends into the cavity of the cavity resonator.

Abstract: A ceramic resonator element having high Q, high dielectric constant, and a low temperature coefficient of resonant frequency is enclosed within a cavity to form a composite microwave resonator having reduced dimensions and weight as compared to a simple cavity resonator. In an exemplary embodiment, a pair of tuning screws extend into the cavity along orthogonal axes to tune the structure to resonance along these axes at frequencies near the fundamental resonance of the ceramic element. Several such cavities can be formed in a short length of waveguide by the use of transverse partitions at spaced intervals and coupling between cavities can be accomplished by using simple slot, cross or circular irises. In each cavity, a mode-perturbing screw is positioned along an axis 45° from each of the orthogonal tuning screws, such that resonance along either of the orthogonal axes is coupled to excite resonance also along the other.

Abstract: A microwave resonator, in particular for a filter, comprising a resonant cavity having positioned therein a plane resonator element, frequency tuning means, and intermode coupling means, the resonator element being made of a dielectric material that is at least approximately in the shape of a parallelogram and being disposed transversely in the cavity in such a manner that the vertices of the parallelogram are short-circuited to one another by the conductive inner wall of said cavity. The resonator has at least one other plane resonator element made of dielectric material in a shape that is at least approximately that of a parallelogram, the resonator elements being placed close together, mutually parallel, and extending transversely to a central axis of the cavity. The frequency tuning means and the intermode coupling means are positioned between the parallel resonator elements.

Abstract: A single mode resonant cavity is adapted to absorb energy via a single excitation mode in a plurality of overlapping absorption bands having different respective resonant frequencies, thereby increasing the resonant bandwidth of the cavity. The high Q-factor cavity may form part of a microwave powered catalytic converter for exhaust gas, and has the advantage that as the cavity warms up and physically expands the coupling efficiency between the cavity and a relatively narrow waveband microwave source remains good.

Abstract: The present invention relates to a tuning device in radio filter equipment for mobile telephony in which one or more cavities in the equipment should be tuned to the right frequency. The invention also relates to a tuning plate including a number of such tuning devices. The tuning device preferably includes regular or square formed depressed parts in the tuning plate. The depressed part converges each to a square formed central plate which is provided with an elevation or bulb. By turning a tuning screw on the equipment a force is developed on the plate and the surrounding depressed parts. This implies that the tuning can be made automatically, more secure and with less risk for intermodulation.

Abstract: An electromagnetic bandstop filter comprises a microwave circuit, at least one microwave resonator, coupling means that couples electromagnetic energy to and from the microwave resonator, and an impedance transformer coupled to, and in series with, the coupling means, wherein the transformer is coupled to the resonator only through the coupling means, and wherein the impedance transformer is shunt coupled to the microwave circuit. The impedance transformer comprises at least two series-connected transmission line sections of different impedances.

Abstract: In one form of the invention, a resonant cavity filter (50) is disclosed, comprising an input port (210) for receiving an input signal, a dielectric resonator (204) in a cavity, the dielectric resonator operable to receive an input signal from the input port and further operable to produce an output signal at a resonant frequency of the cavity, an output port (212) operable to receive the output signal and a tuning plate (308) disposed in the cavity, the tuning plate coupled to a control means operable to cause movement of the tuning plate, thereby changing dimensions of the cavity, the control means operable to determine a frequency of the input signal, retrieve an expected tuning plate position from a memory (514) based on the frequency, and move the tuning plate to the expected position. Other systems, devices and methods are disclosed.

Abstract: A method of producing a microwave resonator comprising a cavity (50) defined, at least in part, by a generally cylindrical wall (64) having an electrically conductive inner surface and containing a generally cylindrical piece of low loss dielectric material (22), characterized by forming a generally cylindrical piece of low loss dielectric material of predetermined size and placing same in a cavity to produce a microwave resonator which operates in a particular mode at a specific frequency at a particular temperature. Microwave radiation corresponding to a further operating mode is then passed into the cavity and then the frequency corresponding to the further operating mode is searched for and measured. A further generally cylindrical piece of dielectric material is produced by scaling from the first piece of dielectric material according to the ratio between the first and second frequencies.

Abstract: The invention relates to a coaxial resonator comprising an inner conductor (12) with walls defining therebetween a free space (24), and a housing portion (13) surrounding the inner conductor (12) and forming an outer conductor of the resonator. In order that connection to the inner conductor could be made very simply, the inner conductor (12) is made of sheet material in which slits (21; 33) extending in the direction of the inner conductor are made so that they form between them a tongue-like connecting part (22; 34) having its free end connected to a printed circuit board (11).

Abstract: A microwave cavity closure structure encloses an upper splitter cavity bounded at its top and bottom by, respectively, a rigid metal plate and a flexible sheet metal dish and (b) a lower combiner cavity bounded at its top and bottom by another such dish and another lower such plate. Each such cavity has a central region occupied by a raised circular boss, and the lower plate bounding the bottom cavity mounts, outward of the central boss, two concentric annular sheet metal rings each having a flat top and peripheral flanges extending from the margins of that top down into annular grooves in the lower plate. One or more rings of dielectric posts are disposed in each cavity radially between the central boss therein and the cavity periphery to vertically space at the ring's location the plate and dish of the cavity by a distance determined by the posts, while concurrently permitting the dish to be flexed in the cavity's central region for cavity tuning purposes.

Abstract: An autotuning combiner particularly for use in combining signals for radio telephony transmission. The combiner has a series of filter cavities each with an adjuster for fine-tuning the cavity to an input carrier signal. The combiner cavities are stabilized from positional drift in the absence of a carrier signal by means of a mechanical brake which holds the adjuster or a pilot signal generator which simulates the absent carrier signal.

Abstract: An acceleration device for charged particles has an acceleration cavity through which passes a beam of the particles. High frequency power from a suitable source is transmitted to the cavity via a suitable transmission means (antenna) to transmit the energy to the particles and so accelerate them. The transmission means is controlled by a suitable control to control the coupling constant of the transmission means when power is applied. Also, the device may have a looped conductor in the cavity controlled by the control to couple to the field in the cavity and to extract power from the field, thereby to control the de-tuning of the applied power relative to the power transmitted to the particles. By controlling the coupling constant and/or the de-tuning, power may be transmitted efficiently to the beam of particles.

Abstract: In a quasi-optical gyrotron an electron beam (1) passes along an electron beam axis (2) and in so doing is compressed by a static magnetic field and forced into gyration, so that it excites in a quasi-optical resonator a standing alternating electro-magnetic field of given frequency. The resonator exhibits two mirrors (4a, 4b) arranged opposite to one another on a resonator axis (5) aligned perpendicular to the electron beam axis (2). In order to generate radiation in a wide frequency range, each of the two mirrors (4a, 4b) of the resonator is arranged in each case on a movable mount (8a, 8b) together with at least one further mirror (4c, 4d). In order to set a specific frequency of the alternating field, it is possible for two mirrors (4c, 4d), corresponding to one another and tuned to the desired frequency, to be brought onto the resonator axis by actuating the movable mounts (8a, 8b).

Abstract: A ferrite tuning arrangement for a resonator includes a ferrite loaded line in the form of a stripline having an inner conductor, an outer conductor and a ferrite disposed between the inner and outer conductors, with the stripline being adapted for coupling to the resonator. A reflecting termination is provided for the stripline and a magnetic circuit is provided for generating a variable premagnetization field for the ferrite in an orientation perpendicular to a high frequency magnetic field existing in the stripline.

Abstract: A radio frequency duplexer filter for a duplex transceiver is disclosed. To prevent spurious signals conducted by flyback responses of the transmit bandpass filter 103 from reaching the antenna (105), a band reject circuit consisting of third harmonic quarter-wave transmission line stubs (601 and 603) are advantegeously coupled to an output transmission line (107). Likewise, to prevent spurious signals conducted by flyback responses of the receive bandpass filter (113) from reaching the receiver (109), a band reject circuit consisting of third harmonic quarter-wave transmission line stubs (605 and 607) are advantageously coupled to an input transmission line (111).

Abstract: A multiplexed microwave filter comprising at least two elementary filters (10, 11) provided with respective coupling antennas of crankshaft or any other shape, and including a common access (14), which access is provided with a crankshaft-shaped coupling antenna which is rotatable about its axis in order to adjust coupling between the antenna and the corresponding elementary filter, in which the common access is situated astride the various elementary filters and includes as many crankshaft-shaped antennas (22, 23) as there are elementary filters (10, 11).

Abstract: An apparatus 10 with gears (22a, 22b, 22c, 25) for adjusting the position of a plate (13) in a cavity (12) and a rack (51) and gear (53) for moving a probe (15) into and out of the cavity is described. The apparatus includes knobs (34, 55) for controlling the movement of the plate and probe. Micrometers (37, 52) measure the precise position of the plate and probe in the cavity. The apparatus allows very precise tuning for selection of a mode of radiofrequency wave in the cavity and fine tuning within the mode.

Abstract: A microwave resonating cavity including a hollow cylindrical body shaped in the form of a parallelepiped and consisting of a dielectric material coated by a metallic layer, said dielectric material having a high dielectric constant having a value greater than 30, and wherein said hollow body includes an upper base, a lower base, an external surface and an internal surface, and further includes a non-metallized area defining a metallized coupling line onto the external surface of the said hollow cylinder and wherein said hollow cylinder has an inner diameter ranging between 3 and 5 mm, an outer diameter ranging between 6 and 15 mm and a height ranging between 5 and 10 mm, and further including a metallic cap welded to the upper base of said hollow body, and further including an adjusting screw for fine adjustment of the resonating frequency.

Abstract: An external motor is coupled to a tuning rod extending into a resonant cavity of a transmitter combiner. A microprocessor tuning control system generates motor control signals that cause the motor to rotate the tuning rod, varying the resonant frequency of the cavity so as to minimize the reflected power from the cavity. Incident and reflected power are detected by diodes in the transmitter cable connecter of the cavity. The standing wave ratio is computed and composed with a threshold value to determine if the cavity needs to be retuned. The microprocessor effectuates reading of digital numbers representing the incident and reflected power and makes a "best effort" attempt to tune the resonant frequency of the cavity to the transmitter frequency, using the motor to rotate the tuning rod.

Abstract: An apparatus that utilizes a solid, dielectric-filled waveguide filter in a microstrip circuit is dislosed. The microstrip circuit couples directly into and out from the waveguide filter through slot openings in waveguide filter walls without penetrating the interior of the waveguide. Adjustment of the coupling is accomplished through varying the length of the slot. Resonant frequency tuning of the filter is accomplished using additional slots, or by removing metallic plating from metallized cavities which extend into the waveguide core from a central region of a waveguide broad wall.

Abstract: A cavity resonator coupling type power distributor/power combiner can be used as a distributing amplifier or a combining unit. A first cavity resonator, having a single coupling terminal, and a second cavity resonator having a plurality of coupling terminals, are coupled by a coupling window or a coupling rod. As a result, a wide bandwidth of microwave electric power can be distributed or combined.

Abstract: A triple mode dielectric loaded bandpass filter has at least one cavity resonating in three independent orthogonal modes. A triple mode cavity can be mounted adjacent to either single, dual or triple mode cavities. Inter-cavity coupling is achieved through the iris having two separate apertures that together form a T-shape. The cavities can be planar mounted. The filter is designed for use in the satellite communication industry and results in substantial savings in weight and size when compared to previous filters.

Abstract: A resonant cavity device--particularly a magnetron oscillator--has a separate resonator coupled to a resonant cavity of the device. The separate resonator consists of a resonant transmission line within which are two multipactor discharge arrangements, one being positioned at a distance along a resonant transmission line which is approximately 3.lambda./4 from the end of the transmission line adjacent the cathode and the other of which is positioned at a distance along the resonant transmission line which is .lambda./4 from the same end of the transmission line. By controlling the multipactor discharges of the multipactor discharge devices appropriately three different frequencies of operation are available.

Abstract: A dual mode filter has a hollow cylindrical longitudinal outer body which is divided by transversely extending disk-like separation walls into a plurality of internal cavities. At least one coupling opening in each separation wall permits coupling of energy from one cavity to another. Said coupling opening being preferably an arcuate opening, in each separation wall, which extends along a constant radius at the outer periphery of the separation wall and over a limited angular span. When the openings are two, they are spaced 180.degree. apart, i.e. opposite one another. Adjacent separation walls are rotatably displaced 90.degree. with respect to each other so that their respective coupling opening(s) is (are) misaligned by 90.degree.. One respective adjustment screw is provided for each separation wall which penetrates through a hole in the outer body into one of the coupling openings in the given separation wall.

Abstract: A standing-wave accelerator including a plurality of accelerating cavities arranged along the axis direction of the accelerator; a plurality of coupling cavities provided between the two-adjacent accelerating cavities; at least one of the coupling cavities is provided with a detuning device for detuning the coupling cavity; and the detuning device is provided to be inserted from a first wall of the coupling cavity to extend until it comes into contact with a second wall thereof, spacedly passed between a pair of inwardly projecting posts.

Abstract: Transmitter combining apparatus includes up to five RF filters (100) coupled to a microstrip combiner (300) for combining up to five input signals for application to a common antenna. The RF filter (100) includes a ceramic resonator (116) sandwiched between first and second compensating discs (114 and 120) and first and second shield plates (142 and 148) for temperature compensation, low loss mounting and heat sinking of the ceramic resonator (116). Good thermal contact between the ceramic resonator (116), discs (114 and 120) and shield plates (142 and 148) is produced by a compressive force exerted by springs (144-147) of shield plate (142) when the top cover (112) is attached to the aluminum housing (124). The resonant frequency of the RF filter is tuned by means of an aluminum tuning shaft (102) and ceramic tuning core (118) which are positioned by brass bushing (133) in top cover (112).

Abstract: An odd order bandpass filter has at least one cavity resonating at its resonant frequency in three independent orthogonal modes. The filter has at least one feedback coupling that is made to resonate and change sign at a center frequency. When the filter has two cavities, one being a triple cavity and the other being a dual mode cavity, the filter can be operated to achieve an elliptic function response. Also, the filter of the present invention can achieve a weight and volume reduction when compared to six-pole dual mode filters.

Abstract: A transmitter combiner includes a plurality of adjacent square prism filters, each of which shares at least one square wall with another of filters. Tuning of the individual square prism filters is accomplished by adjusting the position of tuning rods located in the high electric field region of each cavity. Tuning of each filter is achieved by rotating a control rod perpendicular to and extending through a rectangular end wall to pivot the tuning rod in that filter. In one embodiment of the invention, the control rod extends through a conductive tube attached along a square wall of the filter and perpendicular to the rectangular wall. In another embodiment of the invention, the control rod extends from the center of the rectangular wall and supports the tuning element near the center of the cavity. Temperature compensation is accomplished by variation in the length of the control rod as a function of temperature to compensate for changes in the dimensions of the cavity with the temperature thereof.

Abstract: A dielectric-resonator-stabilized, Gallium-Arsenide-FET, negative resistance oscillator operating in the microwave region incorporating an improved form of dielectric resonator whose resonant frequency is tuned by the addition or removal of metal from the surface of a dielectric tuning plate in the resonator, and a method for tuning the oscillator to the desired frequency range with the resonator in place by use of a laser-trimming device are disclosed.

Abstract: A steerable microwave antenna array having directional characteristics, which includes at least two antenna elements spaced from one another by a predetermined distance, each antenna element defining a controllable directional radiation pattern of a selectable intensity, and having an axis of maximum radiation intensity, and wherein the directional characteristics are derived from the super-position of the radiation patterns, the axes subtending a predetermined angle therebetween, the wherein the improvement provides for feed means connected to each antenna element, each including a photo-conductive element for a selected frequency in the microwave region, so that, upon the photoelectric elements being impinged with a selected intensity of light, the directional characteristics are changed in dependence of at least the difference in the intensity of light impinging on the photo-conductive elements, respectively.

Abstract: A microwave antenna feed network dispenses with the conventional phase shifters. Instead, the required phase relationships between the different individual antenna components is achieved by means of a new device, known as a phase slope equalizer, placed in each feed line. This device is formed of a section of waveguide containing one or more resonant circuit elements. Each element comprises, for example, a pair of spaced inductive posts and capacitive tuning screw, or an inductive iris and a capacitive tuning screw, or a resonant slot. The phase slope equalizer exhibits a substantially constant slope phase shift/frequency response curve extending from a positive phase shift through zero phase shift at midband to a negative phase shift. The device is simpler and smaller than the conventional phase shifter and fewer are required thereby reducing costs.

Abstract: An improved loop coupled YIG resonator has a coupling loop of three sections, a loop section partially encircling a YIG resonator, and two straight end sections. The end sections together with a ground plane enclosing one end of the resonator cavity form a transmission line, the characteristic impedance of which is determined by the distance of the end section above the ground plane. The characteristic impedance is chosen to match the transmission line input to which the coupling loop is connected.

Abstract: An apparatus for changing the phase of a microwave signal comprising:a sample that exhibits the magneto-electric effect;a metal enclosure loaded with said sample; a voltage source; a feed electrode and a ground electrode attached to said sample and to said voltage source so that a voltage difference is created across said sample by said voltage source, said feed electrode connecting said voltage source and said sample by passing through said; a coupling slot in said enclosure that enables microwaves to enter into said enclosure and leave said enclosure after the microwave has been phase shifted and a means for producing a magnetic field inside the metal enclosure.

Abstract: A capacitor arrangement which is especially suited for use in an electronically tunable narrow band tuned cavity filter includes two capacitor plate portions which are juxtaposed one another to form a capacitor. One of the capacitor plate portions may be provided with a recess and with an internally threaded bore which opens into the recess, and an externally threaded trimmer slug may be received in the bore and extend to a greater or lesser degree into the recess and thus to contribute to a greater or lesser degree to the total capacitance of the capacitor. A dielectric spacer may be interposed between the capacitor plate portions to determine the size of the gap therebetween and to maintain the gap size constant.

Abstract: Two collocated, weakly coupled probes, on loop and one dipole, detect the magnetic and electric fields inside a maser cavity. Signals from the probes are compared in phase, and the signal output from the phase detector is applied to a varactor, the reactance of which is coupled into the cavity by a microwave coupler. Alternatively, the varactor may be placed inside the cavity. Any deviation of phase from 90.degree. as detected by the phase detector will then produce an error signal that will change the reactance coupled into the resonant cavity to change its reactance, and thus correct its resonance frequency. An alternative to using two probes is to use a single disk probe oriented to detect both the magnetic and electric fields, and thus provide the error signal directly.

Abstract: An insertion filter is described for existing waveguide without modification. The filter includes a resilient bifurcated dielectric member (11) which conforms to the internal geometry of the waveguide (21). The dielectric member secures the position of a dielectric resonator (15) and a tuning screw (17) and retains their relative positions. A stud (18) is mounted on one of the bifurcations of the dielectric member to compensate electrically for the presence of the member in the waveguide while the dielectric resonator attenuates waveguide energy in a prescribed frequency band.

Abstract: A ceramic resonator element having high Q, high dielectric constant, and a low temperature coefficient of resonant frequency is enclosed within a cavity to form a composite microwave resonator having reduced dimensions and weight as compared to a simple cavity resonator. A pair of tuning screws extend into the cavity along orthogonal axes to tune the structure to resonance along these axes at frequencies near the fundamental resonance of the ceramic element. Several such cavities can be formed in a short length of waveguide by the use of transverse partitions at spaced intervals and coupling between cavities can be accomplished by using simple slot, cross or circular irises. In each cavity, a mode-perturbing screw is positioned along an axis 45.degree. from each of the orthogonal tuning screws, such that resonance along either of the orthogonal axes is coupled to excite resonance also along the other.