Abstract: A microwave filter comprises at least one resonant filter element resonating at a resonant frequency and having a housing, a resonant filter cavity arranged in the housing and a resonator element arranged in the housing. At least two tuning elements are arranged on the housing of the resonant filter element and each extend into the cavity with a shaft portion, wherein the two tuning elements are movable with respect to the housing to adjust the length of the shaft portion extending into the housing and wherein the at least two tuning elements are constituted and designed such that by adjusting the length of the shaft portion of each tuning element extending into the housing a temperature drift of the resonant frequency is adjustable.

Abstract: A frequency modulation assembly includes a self-locking screw, a self-locking adjuster and an elastic member. The self-locking screw has a first external screw thread, the self-locking adjuster has a mounting hole in which an internal screw thread is formed, the self-locking screw is inserted into the mounting hole, and the first external screw thread is engaged with the internal screw thread to achieve a connection between the self-locking screw and the self-locking adjuster, one end of the self-locking screw which passes through the mounting hole is inserted into a ceramic resonance rod in the cavity filter, and the elastic member is connected with the self-locking screw and configured between the self-locking adjuster and the ceramic resonance rod. The frequency modulation assembly can decrease accumulated assembly tolerances, reduce manufacturing cost and improve assembly efficiency, further the elastic member is beneficial to adjust the accuracy of the frequency modulation effect.

Abstract: A resonator includes an inductive element and a conductive cavity surrounding the inductive element. In particular, the conductive cavity surrounds the inductive element such that a capacitance is distributed between the inductive element and the conductive cavity. By distributing a capacitance between the inductive element and the conductive cavity, a high quality-factor resonator can be achieved by the resonator with a relatively small form factor.

Abstract: A radio frequency (RF) filter includes an input port configured to receive a signal, an output port configured to output a signal, and a tuning probe configured to be movable within a tuning probe port to adjust filter characteristics. The tuning probe port is configured to receive the tuning probe therein, and a locking mechanism is configured to lock the tuning probe in the tuning probe port at a desired depth and further configured to prevent movement of the tuning probe in the tuning probe port when the locking mechanism is in a locked configuration.

Abstract: The adjustable resonator according to the invention has a casing, which is composed of walls, a lid and a bottom, a resonator cavity inside the casing and an internal conductor inside the resonator cavity, which internal conductor is in electric contact with the casing. The resonator further comprises a moveable adjustment piece, which comprises a conductive adjustment member, a conductive upper plate, and a dielectric support member. The adjustment member has a stem, which is vertical, and a cap as an expansion thereof. The adjustment member can be moved downwards so that its stem and the fixed internal conductor connected to the bottom of the resonator go within each other. The movement of the adjustment piece in the coaxial resonator first decreases the resonance frequency and then slowly increases it. Therefore the resonator provides a very wide adjustment area for the resonance frequency.

Abstract: A cavity filter defines a cavity with an opening on a top portion thereof and includes a lid to cover the opening of the cavity. A plurality of resonators are secured on a bottom portion opposite to the top portion of the cavity. The lid includes a plurality of bases extending from the lid toward the plurality of the resonators, respectively. A plurality of threaded holes penetrating the lid and one of the bases faces to the plurality of resonators, respectively. Each threaded hole includes a stopper portion extending from an inner surface of the threaded hole inward to form a step defining a hole in communication with the threaded hole. Each threaded hole corresponds to a tuning post to adjust a resonating frequency of the cavity filter.

Abstract: An RF cavity resonator that includes: a resonator chamber for containing an RF field; an RF coupling element coupled to the resonator chamber for introducing the RF field into and extracting the RF field from the resonator chamber; a tuning assembly for causing the RF field to resonate at a desired frequency, wherein at least a portion of the tuning assembly is coupled within the resonator chamber; and a heat transport element included in the tuning assembly for transporting heat from the RF cavity resonator, the heat transport element comprising a phase change material, a housing for enclosing the phase change material, means for circulating the phase change material within the housing, and an electrically conductive surface for isolating the phase change material from the RF field, wherein the phase change material undergoes a phase change during circulation within the housing.

Abstract: A high Q RF cavity resonator loaded with a ceramic disc, the resonator comprising an inner conductive post having a length less than a quarter wavelength. The resonance frequency of the resonator is tunable by changing a distance between a) an outer plate and b) a ceramic disc and an end cap where the ceramic disc is located between the outer plate and the end cap. The resonance frequency can be tuned when the outer plate, ceramic disc, and end cap are in contact with each other by varying a pressure between the contact surfaces of the ceramic disc, the end cap and the outer plate. Temperature compensation allows the resonator to hold a resonance frequency despite changes in temperature, and can be achieved by selecting thermal coefficients of expansion of components holding or placing the ceramic disc and end cap relative to the outer plate.

Abstract: A microstrip-based RF coil for use in an MRI apparatus constructed to perform human head imaging is provided and includes (a) a cylindrical non-magnetic core module having an outer surface and a longitudinal axis, a cylindrical bore extending through the core module along the longitudinal axis and defining an inner surface; and a plurality of conductive strip lines. The strip lines extend parallel to the longitudinal axis on the outer surface of the core module. The coil is constructed such that one or more of the conductive strips are divided into conductive microstrip segments with one or more tuning capacitors being bridged between two adjacent microstrip segmented sections of the conductive strip. The coil also include a shield support cylinder that is disposed concentrically about the core module and is spaced therefrom to receive the tuning capacitors.

Abstract: A system and method for a plunger assembly includes a tuning slug with a bore in the stem, a tuning screw rotatably disposed in the stem, and a coupling assembly to rotatably secure the tuning screw to the slug. The system and method may also include a locking assembly to secure the postion of the assembly.

Abstract: A system and method for a plunger assembly includes a tuning slug with a bore in the stem, a tuning screw rotatably disposed in the stem, and a coupling assembly to rotatably secure the tuning screw to the slug. The system and method may also include a locking assembly to secure the postion of the assembly.

Abstract: An L-C type filter module comprising at least two capacitors and at least one inductor. Each of the capacitors consists of a first elongated element made of conductive material partially fitted in a hole made in a second element made of conductive material, connected electrically to the second elements of the other capacitor(s) or possibly common to the various capacitors, at least the internal lateral surfaces defining the holes being covered with dielectric material, as are the edges of the openings of the holes or perforations and at least parts, or preferably all, of the external surfaces of the second element(s) adjoining the edges, and the coil of each inductor is carried by a support body made of dielectric material, possibly contiguous with the second element(s) or the dielectric coating at least partially covering the external face of each second element.

Abstract: A tunable resonant cavity including a cavity housing having top and bottom walls with a post disposed in said cavity extending from die bottom of the cavity toward and spaced from the top. The length of the post is adjustable to adjust the resonant frequency of the cavity. The materials forming the resonant cavity are selected to provide temperature compensation.

Abstract: A temperature-compensating tuning device is disclosed for tuning and temperature stabilizing the resonant frequency of a dielectric resonator. The tuning device comprises a tuning element in the form of a cylindrical shaft, an inner sleeve coaxially around the tuning element and mating therewith by corresponding sets of threads, and an outer sleeve coaxially around the inner sleeve, and mating therewith by corresponding sets of threads. The outer surface of the outer sleeve may also include threads for mating with threads of a dielectric resonator enclosure. Rotation of the tuning element, inner sleeve and/or outer sleeve can move the tuning element in proximity to a dielectric resonator, which provides the resonant frequency tuning effect. The tuning element, inner and outer sleeves are made of temperature expanding material to cause the tuning element to move in proximity of the dielectric resonator with temperature changes to provide temperature stability to the resonant frequency.

Abstract: An extremely small and inexpensively manufactured physics package for an atomic frequency standard can be provided with a microwave cavity having non-critical dimensions that is driven in a substantially TEM mode by a lumped LC means, the cavity resonant frequency being primarily determined by the lumped LC means. The lumped LC means can be any structure or combination of elements providing, at a selected microwave reference frequency, a resonant inductance and capacitance. Examples of such lumped LC means include, preferably, a rod or wire conductively attached to a wall of the microwave cavity as a lumped inductance and extending into the cavity to form, at its other end, a gap with an opposing cavity wall as a lumped capacitance; or a pair of rods or wires conductively attached to opposing walls and extending therefrom as a lumped inductance to form a gap therebetween as a lumped capacitance.

Abstract: A tuner for radio frequency coaxial cable transmission lines is provided. It requires only one micrometer adjusting screw since the capacitor electrode that mates with the central conductor of the coaxial line is not only curved to give a large area in proximity to the central conductor but is rectangular and much longer than the diameter of the micrometer screw.

Abstract: There is disclosed a radio frequency device having a housing, a cover disposed atop the housing, and a rod. A fastener such as a nut is attached to the rod and engages the cover. When the fastener is rotated, the cover moves with respect to the housing, thereby changing the volume of the cavity defined by the housing. In this fashion, the device may be tuned to different frequencies. In alternative embodiments, the rod is internally threaded and receives a screw that engages the cover. When the screw is rotated, the volume of the cavity is changed and the device may be tuned.

Abstract: A band-stop filter comprises a plurality of resonator units each comprised of an end-shorted coaxial resonator and a variable condenser connected in series therewith, a printed circuit board combining said resonator units in a multistage having thru-holes adjacent a bushing which isolates the inner conductor of the end-shorted coaxial resonator from the printed circuit board. A thru-hole conductor is provided in the thru-hole, and an adjusting screw having a radius is a little larger than the thru-hole. The adjusting screw can have both the proper torque and the electrical connection. The inner conductor surface of the resonator operates electrically as a stator and the adjusting screw operates as a rotor.

Abstract: A coaxial resonance cavity of either the fingered or unfingered variety having a metal heat conducting barbell shaped structure inside the movable tuning plunger to conduct heat from the inner surface of the movable plunger to the inner surface of the fixed stub or directly to the shield to provide for a heat conductive path to the shield to carry heat away from the inner plunger. The barbell is an integral structure machined from stock aluminum, but resembles three right circular cylinders butting end to circular end. The upper cylinder has a diameter appropriate to maintain tight contact with the stub. The lower cylinder has a smaller diameter, appropriate to maintain contact with the movable plunger.

Abstract: A quarter-wave distributed-constant dielectric filter or resonator having a ceramic body which typically is composed principally of barium titanate. The ceramic filter body has one or more resonance holes extending therethrough. A conductive covering of silver or the like on the filter body has a portion formed on the surface defining each resonance hole. Mounted in each resonance hole is a prefabricated capacitor having a first terminal extending from within the resonance hole. The second terminal is electrically coupled to the conductive covering on the surface of the resonance hole. The capacitance of the capacitor or capacitors can be known before they are mounted to the filter body, so that the filter is readily manufacturable to exact electrical characteristics desired.

Abstract: The microwave frequency characteristics of a cavity having a center conducting element and conducting cavity are modified by changing the length of the center conducting element. The resonating structure is comprised of a coaxial member providing the principal resonating surfaces. One end of the coaxial member is coupled to a wall of the cavity surrounding the center conducting member with provision for access to the interior of the center conducting member from a position exterior to the cavity. The second end of the center conducting element is free. In addition, the second end of the resonating element has threads fabricated on an interior surface and a self-locking insert positioned in the threaded portion. A threaded rod is inserted through the self-locking insert and extends beyond the center conducting element into the cavity.

Abstract: A tunable resonant cavity filter structure is disclosed which includes an enhanced ground return internal to the cavity which effectively eliminates generation of deterioration wide band noise and optimizes unloaded Q as well as rending resonant frequency stable with vibration. In its preferred form, the enhanced ground return is in the form of a ground return clip with reliant radial projections that mate with the threads of the threadable tuning element used to determine final operating frequency. The radial projections are deflected in cantilever fashion so as to generate sufficient pressure to break thru any oxides in the tuning element threads and ensure metal-to-metal contact.

Abstract: The disclosure is directed to a dielectric material coaxial resonator provided with an improved resonance frequency adjusting mechanism which is arranged to eliminate deviations of the resonance frequency after adjustment for adjusting the resonance frequency.

Abstract: A waveguide bandpass filter having multiple waveguide sections including alternating ridge waveguide sections and evanescent waveguide sections. The ridge waveguide sections define a resonant cavity and the evanescent waveguide sections reactively load the resonant cavity thus intercoupling the ridge waveguide sections so as to provide a low loss filter having high attenuation, not only at adjacent stop band frequencies, but also at harmonics of the pass band.

Abstract: An h.f. electrical network consists of a transmission line device in the form of a closed cavity having two end plates between which extend four quarter wave resonators positioned symmetrically about an axis passing through both end plates. The device is provided with four ports connected to two pairs of transmission line loops each of which couple equally into two adjacent resonators. The device exhibits frequency selective properties and can be used to couple two carrier frequencies into a common antenna while maintaining electrical isolation between the two signal sources.

Abstract: A coaxial dielectric resonator for VHF and/or UHF band comprising a generally cylindrical dielectric having inner surface and outer surface. The inner and outer surfaces of the dielectric are respectively covered by outer and inner conductors and these conductors are connected at one end of the dielectric. An adjusting screw for adjusting resonance frequency is provided at the other end of the dielectric which is covered by a lid while holding a gap between the adjusting screw and the lid. A microwave filter using a plurality of the coaxial dielectric resonator is further described.

Abstract: A dielectric resonator employing TM.sub.010 mode or its variation mode, and including a cavity resonator and a columnar inner dielectric member accommodated within the cavity resonator a region being formed at an end face of the inner dielectric member so as not to contact the cavity resonator, and a resonant frequency adjusting member being adapted to be movable toward or away from the region, thus adjusting the resonant frequency through variation of a capacitance value in a path passing through the columnar dielectric member, the resonant frequency adjusting member, and the cavity resonator.

Abstract: The microwave resonator includes an enclosed resonator housing and a hollow central conductor having one end fastened to a bottom of the resonator housing and extending toward a top wall of the resonator housing. The other end of the central conductors is spaced from the top wall and includes an adjustable bellows assembly disposed coaxial of a longitudinal axis of the central conductor. A non-rotating, axially movable drive shaft is disposed coaxial of the axis of the central conductor within the central conductor. One end of the drive shaft is fastened to the bellows assembly and the other end of the drive shaft is coupled to a drive means disposed in the bottom wall to cause axial movement of the drive shaft to adjust the axial length of the bellows assembly and, hence, the axial length of the central conductor to adjust the resonant frequency of the microwave resonator.

Abstract: Apparatus for frequency tuning a waveguide cavity comprises a retainer ring and a knob that are threaded onto a plunger in a spaced apart relationship, with the plunger extending into the cavity. Means is provided for preventing rotation of the plunger and for securely rotatably mounting the knob on the cavity. Set screws in threaded holes extending through the knob protrude into blind holes in the ring for mechanically coupling them together. Lightly threading the screws into the blind holes reduces backlash in the threads so that rotation of the knob, and thus the ring, causes smooth and even movement of the plunger in the cavity. Tightening the screws firmly in the blind holes binds the threads on the knob, ring and plunger for preventing further rotation of the knob and movement of the plunger.

Abstract: The invention is a microphonics suppression means for a high frequency resonant cavity. The resonant cavity is used in a RF oscillator to generate UHF/VHF frequencies. The resonant cavity comprises an outer wall portion, a center conductor portion, a tuning slug and a plurality of coupling probes. The coupling probes, tuning slug and center conductor are held in a fixed relationship by a microphonics suppression means made of a low dielectric material which fits over and around the center conductor and encapsulates the coupling probes and collars the tuning slug. The microphonics suppression means reduces the effect of microphonics on the output signal of the RF oscillator, thus allowing a clean output signal suitable for high power applications.

Abstract: There is provided a resonator comprising principally a hollow metal finger integral with the wall of a guide or a cavity. A metal plunger, coated with a fine dielectric layer, of fairly low permittivity, is able to slide inside the hollow metal finger to cause the tuning frequency of the cavity or the susceptance coupled to the guide to be varied. This layer may be formed from Teflon.

Abstract: A transmission line cavity comprises an outer conductor and a center conductor. The cavity is in combination with a source, such as a power tube, for establishing electromagnetic waves within the cavity. The impedance of the center conductor may be changed, for example by changing the series inductance, to vary the resonant frequency of the cavity.

Abstract: A dominant TEM mode and a pair of spatially orthogonal TE.sub.11 modes suitably excited at the input ports of a coaxial waveguide commutator portion of a coaxial waveguide commutation feed network are employed to generate a commutatable low-sidelobe amplitude distribution at symmetrically disposed peripheral output ports of the coaxial waveguide commutator. The resulting low-sidelobe amplitude distribution can be used to feed radiating elements of an associated circular phased array antenna. The coaxial waveguide commutator is configured, inter alia, with a linearly tapered inner conductor surrounded by a uniform tube outer conductor to achieve a smoother TEM-dominant mode characteristic impedance transition from the input port plane to the output port plane thereof. Employment of this feed geometry, in conjunction with balanced four-port feeding of the coaxial waveguide commutator which inhibits the higher order TE modes, increases the bandwidth capability while maintaining low insertion loss.

Abstract: A band-reject filter comprises a resonator with an adjustable resonator rod which is mounted in proximity to a co-axial assembly. The coupling rod passes thru the inner conductor of the co-axial assembly and extends into the resonator. At the end of the rod inside the resonator there is a coupling disc. Means are provided to adjust the distance between the resonator rod and the disc. The frequency rejected by the filter can be adjusted by either adjusting the length of the resonator rod or by adjusting the distance between the disc and the resonator rod.

Abstract: A coaxial resonator comprising an outer conductor with closed and open ends, an inner conductor concentrically disposed in the outer conductor to establish a short circuit at the closed end and an open circuit at the open end, and a dielectric member mounted in the open circuit between the outer and inner conductors. An electrode is connected to the open circuit end of the inner conductor with a spacing from the dielectric member. A conductive plate, having a smaller surface area than that of the electrode but larger than the transverse cross-sectional area of the inner conductor, is provided between the dielectric member and the electrode. The dimensions of the conductive plate is appropriately chosen to accommodate frequency variations which might occur as a result of a connection with an external circuit.

Abstract: An RF tank circuit for a transmitter power amplifier stage including a half-wave length "folded" coaxial transmission line as an anode tuning device. The tank circuit has a grounded outer conductor and an ungrounded inner conductor, the latter to be operated at a high RF potential. The outer conductor is connected electrically to a third conductor which is adjustably extensible into the ungrounded inner conductor, hence, suggesting a folded effect for the outer conductor and the third conductor in combination. The third conductor has a bellows which can be expanded or contracted by drive means disposed exteriorly of the cavity, thereby to fine-tune the cavity to a selected frequency. The third conductor has mounting means which permit its extension into the inner conductor to be variable, thus allowing for coarse adjustment of the bandwidth, prior to the fine-tuning accomplished by suitable bellows-drive controls.

Abstract: A device to suppress the generation of second harmonic frequencies in a power amplifier tank circuit such as may be used in a radio frequency transmitter. The present invention employs a device connected between the outer conductor (which is normally at ground potential) and the inner conductor. Specifically, the device utilizes a metal strap, such as a copper strap, which is connected to the inside surface of the outer conductor in an electrically conductive manner and which is also connected to a capacitor disk movably mounted with respect to the inner conductor. The capacitor disk is mounted to an insulating arm or rod and may be projected back and forth within the space between the outer and inner conductors, thereby adjusting the impedance of the device. By sliding the rod toward the inner conductor, the loop formed by the copper strap becomes more straightened thereby changing the inductance of the circuit.

Abstract: A resonant cavity of a microwave generator, such as a magnetron oscillator, is provided with a tuning piston which is rectilinearly displaceable between two terminal positions, corresponding to respective limiting frequencies, by means of a rotating crankshaft whose eccentric portion constitutes the inner race of a ball or roller bearing. The outer race of that bearing rolls, directly or through the intermediary of a captive spherical or cylindrical coupling member, on a transverse face of the tuning piston held in contact therewith by spring pressure.

Abstract: A frequency band filter includes a plurality of coupled elementary resonator cavities defined by pistons disposed within a coaxial line. The position of the pistons along the line is adjustable thereby providing selectable tuning.

Abstract: A high frequency miniaturized dielectric resonator is disclosed. The resonator includes an elongated dielectric member axially hollow at least in part of its cross section. A conductor surrounds the dielectric member, and a metal rod is inserted into the hollowed part of the dielectric member and coupled to the conductor. This structure supports resonance in a hybrid mode including the TEM mode and the TE.sub.10g mode (g being a positive number).

Abstract: A resonant cavity of a microwave generator, such as a magnetron oscillator, is provided with a tuning piston which is displaceable between two terminal positions, corresponding to respective limiting frequencies, by means of a rotating crank-shaft whose eccentric portion is hugged by a nonrotatable follower ring suspended between two flexible wires or blades extending generally radially outward from diametrically opposite points of the ring. A yoke spacedly surrounding the ring is provided with two oppositely extending tubular arms in which the wires or blades are received with clearance while being fastened to the ends of these arms remote from the yoke; the tuning piston is rigidly connected with one of the two arms.

Abstract: A resonant cavity of a microwave generator, such as a magnetron oscillator, is provided with a tuning piston which is displaceable between two terminal positions, corresponding to respective limiting frequencies f.sub.1 and f.sub.2, by means of a rotating crankshaft to which the piston is coupled by a linkage including a pitman with a substantially linearly guided extremity remote from the crankshaft axis. The length p of the pitman, measured between the pivotal axes of its extremities, is related to the eccentricity e of the crankshaft by the expression ##EQU1## where q is the length of the stroke of the linearly guided extremity between its extended dead-center position and an intermediate position in which the operating frequency of the generator has its mean value (f.sub.1 +f.sub.2)/2. With this dimensioning, the frequency varies as a sinusoidal function of the crankshaft angle and is therefore proportional to the output voltage of an angle sensor coupled with the crankshaft.

Abstract: A coaxial resonator is provided having an outer conductor with top and bottom closures and a substantially central opening through the top closure through which a tubular member forming a center conductor extends. The center conductor also comprises a plunger which is moveable within the tubular member such that the electrical length of the center conductor can be varied to effect tuning of the resonator.The tubular member and the plunger are spaced apart in slidable relationship one with the other and as the bottom end of the tubular member represents essentially a short circuit, at that point there is no physical electrical contact provided between the tubular member and the plunger, thus overcoming several disadvantages of prior art resonators which utilized "finger" electrical contact at that point.

Abstract: The coil form for a helical resonator is comprised of two sections connected by a flexible joint. The coil form/winding assembly is positioned within a cavity such that the ends of the coil forms are affixed to the cavity walls. A tuning screw threads into the cavity wall in tuning relation to the coil.The resulting resonator structure maintains a low frequency drift characteristic over a wide temperature range due to the fixed tuning screw to coil spacing. Strain to the structure due to thermal stress is relieved by the flexible joint.

Abstract: Coaxial, one-quarter wavelength resonant primary and secondary resonators are employed in conjunction with a tetrode tube to provide, for example, 55 Kw (kilowatts) of output power for VHF, high-band television broadcasting. Coupling between the two resonators is accomplished by connecting an inductance between the center conductors of the resonators. The effective inductance of this connection is varied (and thus the coupling of the resonator circuits is also varied) by the addition of a variable capacitor in series with the inductive connection.

Abstract: Cavity resonators, preferably thermocompensated, with a straight-line frequency tuning, tuning elements of which move along a straight-line forced trajectory, and microwave circuits that contain such cavity resonators. At least one tuning element is connected to the cavity, made up of structural elements that are displaceable along a forced trajectory when the elements are in a forced coupling with a straight guide path formed on the structural element. The latter can be swung around an axis which is perpendicular to the direction of movement of the tuning element, the latter being provided with a roller that bears against the guide path. The cavity resonators are furthermore provided with frequency-linear adjusting members that can be displaced along the straight forced trajectory on the latter, also provided with a roller which bears against the guide path that is in a forced coupling with the structural element.