Abstract: The switching element is provided in a state of being electromagnetically coupled to the cavity resonator of the high frequency oscillator; the bias voltage applying terminal is connected to one electrode of the switching element; another electrode of the switching element is electrically connected to the cavity resonator (the anode shell in FIG. 1); the metal plate having a size enough for reflecting an electric wave to be transmitted before and after the switching element in a high-frequency manner is provided at any one end of the switching element; and by applying a bias voltage to the switching element and varying that, a reactance of the switching element is changed and a resonance frequency of the cavity resonator is varied. By this method, an oscillation frequency can be varied greatly relative to a small change in a bias voltage.

Abstract: The switching element is provided in a state of being electromagnetically coupled to the cavity resonator of the high frequency oscillator; the bias voltage applying terminal is connected to one electrode of the switching element; another electrode of the switching element is electrically connected to the cavity resonator (the anode shell in FIG. 1); the metal plate having a size enough for reflecting an electric wave to be transmitted before and after the switching element in a high-frequency manner is provided at any one end of the switching element; and by applying a bias voltage to the switching element and varying that, a reactance of the switching element is changed and a resonance frequency of the cavity resonator is varied. By this method, an oscillation frequency can be varied greatly relative to a small change in a bias voltage.

Abstract: A highly-reliable electronic frequency tuning magnetron comprises an anode for forming a resonant cavity which is segmented into a plurality of spaces in an inner periphery side of a cylindrical anode shell, a cathode provided at the center of the anode shell along its cylindrical axial direction and an exhausted structure having a coaxial central conductor which is connected to the inside of the cavity of the anode shell and is coupled thereto in a high-frequency manner, wherein the coaxial central conductor is externally led through a wall of the exhausted structure via a through-hole and the through-hole is covered by a dielectric portion placed between an external conductor for constituting the coaxial central conductor and the central conductor, wherein a portion of the led coaxial central conductor is conductively connected to a switching element.

Abstract: A magnetron (2), a launcher (4) which extracts the output power of the magnetron (2), an impedance generator (5) having one terminal connected to the output terminal of the launcher (4), and a reference signal supplier (6) connected to the other terminal of the impedance generator (5) are included. The reference signal supplier (6) supplies, to the magnetron (2), a reference signal lower in electric power and stabler in frequency than the output from the magnetron (2). The oscillation frequency of the magnetron (2) is locked to the frequency of the reference signal by injection of the reference signal. The impedance generator (5) can reduce the change width of the oscillation frequency of the magnetron (2) by adjusting the load impedance of the magnetron (2). This implements a magnetron oscillator (1) which has high frequency stability and does not fluctuate the frequency even when the output power is changed.

Abstract: An optically tuned magnetron oscillator employs materials whose electrodynamic properties are altered by the absorption of light. A probe constructed from a leaky dielectric light guide coated with a photoconductive material is inserted into each of the magnetron's cavities. When light is injected into the light guide, it leaks into the coating where it is absorbed, creating free charge carriers whose presence alters the dielectric properties of the material, thereby perturbing the resonant frequency of the cavity. The frequency can be controlled by varying the amount of light injected into each of the optical probes. When no light is present, the resonant frequency of the magnetron cavity will be at one extreme of its operating band; when the light is at full intensity, the change in the properties of the probe will be maximum as will be the change in the resonant frequency.

Abstract: Improved magnetron oscillators that controllably form a plasma within each of its resonant cavities to rapidly change the resonant frequency of each cavity. The present invention also provides for frequency tuning methods for use with magnetron oscillators. The plasma is controllably formed in one or more subcells of each resonant cavity in a manner that alters the electromagnetic field within each cavity. Preferably, a magnetized collisional plasma is controlled to rapidly change the resonant frequency of each cavity. However, many types of plasmas may be used to implement the present invention. Controlling formation of the plasma within each cavity tunes the magnetron oscillator on a submillisecond time scale.

Abstract: A crossed-field device comprises a cathode having an electron emitting surface and an anode structure radially spaced from the cathode. The anode structure has a plurality of vanes extending in radial directions of the cathode with an interaction region defined between the electron emitting surface of the cathode and innermost radial ends of the anode vanes. First and second magnetic polepieces are respectively disposed at first and second axial ends of the cathode and have respective magnets coupled magnetically thereto. The polepieces direct magnetic flux from the respective magnets to define an axial magnetic field through the interaction region. The polepieces are electrically isolated from the anode structure. An anode modulator is adapted to provide a voltage potential between the anode structure and the cathode to define a radial electric field through the interaction region.

Abstract: An improved low power pulsed anode magnetron is provided having a cylindrical cathode centrally disposed within a plurality of radial anode vanes. An interaction region is provided between the surface of the cathode and the anode vane tips. A ratio of the anode-to-cathode space over the center-to-center distance between adjacent vane tips is within a range between 0.95 and 1.05. The cathode is joined to a magnetic polepiece assembly which channels magnetic flux to the interaction region. Both the cathode and the polepiece are mechanically adjustable from external to the magnetron to reposition the cathode and polepiece with respect to the anode vanes. The cathode surface is formed from an active nickel alloy which is cleaned by a chemical process followed by a high temperature and vacuum firing. An emissive surface is applied over the cleaned cathode surface.

Abstract: There is provided a tunable high power magnetron. An annular anode circumscribes a cathode and contains a plurality of resonating cavities. The volume of the resonating cavities determines the output frequency of the RF energy emitted by the magnetron. The volume of the cavities is varied by changing the position of movable, electrically conductive back walls.

Abstract: A semiconductor diode is connected across the cathode-to-anode path of a magnetron and through a storage capacitor and collector resistor to a supply voltage for enabling charging of the capacitor. A control pulse causes a switching transistor to conduct to discharge the capacitor through its collector-to-emitter path, an emitter resistor, and the magnetron, for causing the latter to oscillate. A feedback signal representative of the difference between the magnetron output frequency and a reference frequency is applied to a linear amplifier transistor which conducts through the emitter resistor for controlling the current flow through the switching transistor and the operating frequency of the magnetron.

Abstract: A apparatus for tuning a resonant cavity of a magnetron is provided which prevents undesired frequency fluctuation during thermal cycling or vibration. The magnetron has an axially disposed resonant cavity comprising a plurality of radially disposed anode vanes. Alternating ones of the vanes are electrically connected together by a first and a second strap, respectively. The tuning apparatus comprises a tuner shaft having a threaded outside diameter, a vertical gear having a threaded inside diameter engaging the threaded outside diameter of the tuner shaft, and a worm gear engaging the vertical gear. Rotation of the worm gear translates to axial movement of the tuner shaft. A ceramic cylinder is coupled to the tuner shaft at an end adjacent to the resonant cavity, and extends into a space defined between the first and second straps by the axial movement of the tuner shaft. Disposition of the ceramic cylinder within the space alters capacitance measurable between the straps.

Abstract: A low-torque tuning apparatus is provided for use in a magnetron having an electron emitting cathode coaxially disposed within an anode cavity. The tuning apparatus includes a tuner drive capable of reciprocating axial movement relative to the magnetron. The tuner drive has a plate forming a portion of the cavity such that periodic changes in position of the plate by movement of the tuner drive alter a resonant characteristic of the cavity. Axial movement of the tuner drive is guided by a diaphragm at a first portion of the tuner drive and a double bellows at a second portion of the tuner drive. The diaphragm and double bellows have a first spring bias which permits the axial movement while precluding radial movement of the tuner drive and tends to return the tuner drive to a generally null position relative to the magnetron. The double bellows further provides a vacuum seal between the cavity and an atmosphere external to the magnetron.

Abstract: A magnetron is tuned by a co-axial transmission line co-axial with the axis of the magnetron and a radial transmission line linking the co-axial line to a plurality of sampling points symmetrically positioned on the end of the magnetron. A fraction of the R.F. power in the magnetron passes into the transmission lines and vice versa, so by altering the resonant frequency of the transmission lines the frequency of the RF power in the magnetron can be controlled.

Abstract: The performance of a magnetron may be degraded by its output frequency changing. This degradation may be reduced by fixing a resonator element in the magnetron's output waveguide enabling temperature stabilization to be achieved and also permitting the output spectrum of the radiation to be narrowed.

Abstract: A frequency control system is provided for controlling the radio frequency of a mechanically tuned coaxial magnetron under a wide variety of environmental conditions by initially tuning the magnetron according to resident tuning data and in response to a received frequency command signal, directly measuring the frequency of the magnetron output, comparing the frequency command signal with the actual frequency of each of a series of sampled output pulses, modifying a dynamically adapting calibration function according to any differences found during the comparison, retuning the magnetron according to the modified calibration function, and repeating the process to maintain the magnetron output frequency in agreement with frequency command signals. The coefficients of the calibration function converge to an optimum set of values within a few pulses.

Abstract: A magnetron includes a cathode and vane type anode structure. The frequency of oscillation of a microwave output signal of the magnetron is tunable by means of a tuning member, which is in the form of an annular plate arranged adjacent resonant cavities of the magnetron. The frequency of oscillation is determined by the position of the tuning member relative to the resonant cavities. When it is wished to tune the magnetron output frequency a current is passed along a path defined by the tuning member. This causes axial forces to be exerted on the tuning member so that it moves. Since the current is arranged to pass through the tuning member itself, the device is particularly simple, no actuating mechanisms or drive coils, for example, being necessary.

Abstract: The present invention provides a vircator with improved efficiency. An elongated anode is aligned with an elongated cathode so as to produce an elongated virtual cathode when a direct current voltage source is electrically connected to the elongated cathode. A surface wave having a velocity near the velocity of light will be produced on the virtual cathode. Waveguide means enclosing the virtual cathode is disposed so as to propagate microwave radiation in a direction parallel to the direction of elongation of the cathode, anode and virtual cathode. The waveguide is designed to match the phase velocity of the microwave to the velocity of the virtual cathode surface wave.

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 tuning assembly (42) is disclosed for selectively oscillating the frequency of an electromagnetic field within a hermetically sealed pulsed magnetron (12), comprising a rigid, hermetically sealed housing (14), apparatus for generating the electromagnetic field therewithin (32, 34, and 36), and elements for defining a cavity (30) within the housing for establishing the frequency of the electromagnetic field. The tuning assembly (42) includes electrically conductive members (54) mounted for linear movement within the cavity (30) to oscillate the established frequency. Elements (52) disposed within the rigid housing (14) are provided for mounting the electrically conductive members (54), and are adapted for oscillatory movement at a predetermined mechanical resonant frequency to move the electrically conductive members (54) linearly.

Abstract: In a magnetron a spinner (22), rotatable on a longitudinal axis (x) has a number of evenly spaced markings formed circumferentially on an exterior surface. The markings are sensed, as the spinner rotates, by a photo sensitive transistor (PT) coupled to window (26) in the vacuum envelope of the magnetron by a fiber optic pipe (FP1). The periodicity of pulses, generated by the transistor in response to movement of markings past the window, is divided in a network (43) to generate a succession of further pulses. The further pulses are then counted in circuit (44) and the instantaneous count compared with reference frequency values stored in memory (46) to generate an output signal O/P(1) related to the instantaneous magnetron frequency.

Abstract: A bearing arrangement in a tunable magnetron, in which a sleeve-shaped body (12) is journalled on a central column (10) by means of two bearings (14, 15). The distance between the inner rings (18, 19) and outer rings (22, 23) of the bearings is determined by distance means (20, 21) which generally can be sleeve-shaped. According to the invention, at least one distance means, suitably both distance means, is temperature compensated by being composed of an odd number of partial elements (30-32; 37-39). The elements all extend in the longitudinal direction of the distance means, and each distance means includes two end elements (30, 32; 37, 39) which bear against the respective bearing part (18, 19; 22, 23) and an intermediate element (31; 38). The elements in each distance means are in such force-transmitting connection with each other that, with temperature variations, two adjacent elements impart to the distance means length variations in opposite direction.

Abstract: An arrangement for transmission of a predetermined fixed frequency by means of a tunable high frequency transmitter tube, such as a magnetron, the tuning of which can be varied periodically by means of a rotatable tuning body driven by a motor. The arrangement comprises a locking hook (22) which is pivotably mounted on a part connected to the rotatable tuning body and cooperates with a stationary locking disc (11), having a locking notch (14) with a stop surface (15). The locking hook (22) cooperates with spring means (28, 30) urging the active end of the locking hook towards the stationary locking disc (11). The locking hook (22) has furthermore a counterweight (35) situated at the opposite side of its rotation axis (23) as compared with the active end.

Abstract: A rotatable tuning body is driven by a positioning motor such as a stepper motor, for varying the tuning frequency of a magnetron. The motor rotor is situated within the evacuated space of the magnetron and is integrated with the tuning body. The motor stator is fixed to the magnetron envelope, and preferably forms part of the vacuum-tight envelope.

Abstract: A resonant-cavity type electronic tube having mechanically-operable tuning vanes associated with its resonant-cavity structure and disposed within an evacuable envelope. A support member is provided within the envelope for adjusting the tuning vanes relative to the resonant-cavity structure, so as to tune the frequency of resonance of the structure step-wise in accordance with a predetermined program. The tuning is carried out with a step motor, having a stator and armature with the envelope having a portion extending between the stator and armature for enclosing the armature within the evacuable space containing the tuning vanes and the resonant cavity structure. The armature is coupled to the tuning vanes for altering the position thereof relative to the resonant-cavity structure in fixed relation to the displacement of the armature relative to the stator. Electrical signals are coupled to the stator for establishing a programmable series of displacements of the armature relative to the stator.

Abstract: A tunable, coaxial-vacuum magnetron is shown having a cathode surrounded by an anode within a surrounding evacuated anode cavity. Located between the cathode-anode interaction space and an output from the anode cavity is a tuning mechanism which includes a single symmetrical ceramic tuning rod that is adjusted along its axis into and out of the anode cavity. The adjustment mechanism includes a tuning nut rotatably mounted in a tuning housing which turns to move a threaded shaft along the axis thereof. Separating the threaded shaft from the anode cavity is a bellows attached to the tuning housing and to which is attached the symmetrical tuning rod for sealing the vacuum cavity.

Abstract: A frequency agile magnetron employs an altitude compensation vacuum envelope external to the vacuum envelope of the magnetron. The tuning assembly of the magnetron includes a tuning plunger coupled through a first bellows assembly to one end of a tuning shaft. The tuning shaft is coupled at its opposite end through a second bellows assembly to the compensation vacuum envelope. When the two bellows assemblies are identical, atmospheric forces acting upon the tuning shaft are balanced at any altitude. Translation of the tuning assembly is provided by an actuator such as a linear motor coupled to the tuning shaft. Improved transfer of heat from the resonant cavity is provided.

Abstract: A co-axial magnetron is provided with a cavity whose resonant frequency can be very rapidly altered in a cyclic manner so that the microwave output frequency of the magnetron can be chosen to lie within the available frequency band of the cavity. The cylindrical walls of the co-axial resonant cavity are constituted by or coupled to the inner surfaces of one or more tuning forks which are maintained in vibration by externally mounted electro-magnetic transducers. As the tines of the tuning forks vibrate, the effect is to cyclically increase and decrease the effective diameter of the cavity, thereby changing its resonant frequency. An adjustable end plate can be provided for the cavity so that fine tuning or slow rate tuning can be provided in addition to the frequency agility provided by the tuning fork.

Abstract: Coherent microwave radiation is generated in and transmitted through a waveguide/drift tube by means of an injected relativistic electron beam the parameters of which, in combination with the waveguide/drift tube geometry and dimensions effect a virtual cathode oscillation condition within the waveguide/drift tube. Tuning of the device is accomplished by manipulation of the relativistic electron beam parameters and/or waveguide/drift tube physical dimensions.

Abstract: A tuning assembly is disclosed for selectively oscillating the frequency of an electromagnetic field within a hermetically sealed device, which device includes a rigid, hermetically sealed housing, apparatus for generating the electromagnetic field therewithin, and elements for defining a cavity within the housing for establishing the frequency of the electromagnetic field. The tuning assembly includes electrically conductive members mounted for linear movement within the cavity to selectively vary the volume of the cavity to oscillate the established frequency. Elements disposed within the rigid housing are provided for mounting the electrically conductive members, and are adapted for oscillatory movement at a pre-determined mechanical resonant frequency to move the electrically conductive members in the described linear manner. Finally, a power source is provided exterior to the rigid housing and is magnetically coupled to the mounting elements for exciting the mounting elements.

Abstract: Two variable-frequency microwave generators, i.e. a coaxial magnetron producing outgoing waves and a voltage-controlled oscillator emitting a heterodyning signal for incoming waves of a radar transceiver, are continuously tuned by a pilot signal modifying their operating frequencies with a predetermined constant separation. To maintain this correlation, the tuning circuit of at least one microwave generator responds to the pilot signal through the intermediary of a read-only memory which, on being directly or indirectly addressed by that signal, emits stored setting instructions for the respective generator.

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 co-axial magnetron in which the microwave output frequency can be rapidly altered within a particular frequency band. A movable tuning plate is coupled to a mechanical tuning fork which is set into vibration by an alternating voltage applied to a solenoid.

Abstract: A multipactor discharge tuned resonant cavity device, e.g. a magnetron, is irradiated with X-rays in order to assist the starting of the multipactor discharge. The X-rays are produced by electrons striking the surface of the magnetron anode.

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 circuit for the modulation of the frequency of radiation produced by a magnetron includes a directional coupler connected to the output port of the magnetron, a circulator coupled between the output port and a load, and a phase shifter connected between the directional coupler and the circulator.

Abstract: In a vane type magnetron oscillator a resonant co-axial transmission line breaks through the wall of the anode block to couple to two adjacent cavities on either side of a vane. Positioned at a point at which a high radio frequency voltage appears in operation approximately an odd multiple of a quarter wavelength (preferably 3.lambda./4) from the end of the transmission line adjacent the cavities is a multipactor discharge arrangement. This latter consists of two co-axial cylinders one connected to the inner conductor and the other to the outer conductor of said transmission line. The transmission line extends beyond the multipactor discharge arrangement to a total length approximately half wavelength or a multiple thereof and is short circuited at its end.

Abstract: A multipactor discharge tuned resonant cavity device, e.g. a magnetron, is arranged with two multipactor discharge electrodes so that in a discharge condition a net current flows from one electrode to the other. The net current is used to create a self-bias voltage on one of the electrodes which affects the operating frequency of the device.

Abstract: Cavity resonator electronic tubes, in particular magnetrons, with an electronic tuning system. The tuning systems in accordance with the invention consist of multipactor elements arranged directly within the resonant volumes of the tube cavities. Frequency tuning can be effected either by switching between two predetermined frequencies or by continuous change of the frequency.

Abstract: A magnetron adapted for operation with an ungrounded power supply, has mounted thereon and tightly coupled thereto an external cavity resonator having coaxial first and second openings in opposite walls thereof. The magnetron has coaxial output connection members including a hollow outer connection member communicating with the interior of the cavity resonator through the first opening, and an internal connection member extending entirely through and beyond the resonator via the first and second openings. The cavity resonator is galvanically insulated from the magnetron by teflon insulation which provides capacitive coupling therebetween. The cavity is coupled to a load which may be grounded. The cavity resonator is formed from a closed section of wave guide, two embodiments of which are disclosed.