Abstract: A Gaussian-beam oscillator for microwave and millimeter wave comprising a negative resistance amplifier circuit which produces and amplifies a high-frequency signal, a resonator consisting of a pair of reflecting mirrors, which consist of a spherical mirror and a planar mirror or two spherical mirrors, and a wave path which transmits the high-frequency signal between said resonator and said negative resistance amplifier circuit, one reflecting mirror of said resonator having an electromagnetic wave coupling region constituted as a circular partially transparent mirror surface region having its center on the optical axis, the other reflecting mirror having a strip element provided at the center of the optical axis and on the rear surface of said strip element having a coupling region for coupling with said wave path, said one reflecting mirror constituting said resonator and having the electromagnetic wave coupling region having a higher reflectance than the reflectance of the other reflecting mirror.

Abstract: The dielectric resonator assembly includes a housing having interior surfaces defining a resonant cavity and a dielectric resonator within the cavity. The dielectric resonator is a ceramic having a high dielectric constant and generates pulses at a desired frequency of oscillation. A pedestal supports the dielectric resonator within the resonant cavity so that it spaces the resonator apart from each of the interior surfaces of the cavity. The assembly also includes a transmission line for transmitting the pulses which pass through at least one of the interior surfaces and has an interior portion spaced apart from the remaining interior surfaces of the cavity. The interior portion of the transmission line is positioned proximate to and in magnetically coupled relationship with the dielectric resonator.

Abstract: The invention is directed to the structure of a YIG-component. The component comprises a magnetic circuit for generating an homogeneous magnetic field in an air gap of the magnetic circuit and at least one ferrite crystal (81) arranged in the air gap. The magnetic resonance frequency of the ferrite crystal (81) may be controlled dependent on the strength of the homogeneous magnetic field. The magnetic circuit is enclosed in a cavity of a housing (53, 55) arranged for mechanically relieving the magnetic circuit from external influence. The housing (53, 55) may be formed from a material selected at will. The magnetic circuit is arranged in a specifically shaped seat for accurate positioning of the air gap in the housing (53, 55). A foundation formed in the housing (53, 55) is provided for supporting a YIG-unit (75) comprising the ferrite crystal (81) with correct positioning of the ferrite crystal in the air gap.

Abstract: An RF voltage/current sensor apparatus comprising a plurality of transmission lines coupled through resistive means to voltage sense circuitry. The voltage sense circuitry utilizes transistor technology thereby reducing the use of switching relays, transformers and diodes thereby providing an apparatus operational over a frequency range from approximately two megahertz to two gigahertz.

Abstract: A frequency synthesizer, which controls the fluctuation of frequency not only of a long period but also a short period, ensures a wide frequency control range and can be realized at a low cost, can be obtained.

Abstract: A voltage controlled push-push oscillator is provided having a variable frequency output over a range of frequencies. Usually, the range of frequencies is in the microwave range. The configuration is such that the collectors of a pair of transistors are tied together, and an inductive reactance is provided across the base and collector of each of the transistors, with the emitters of the pair of transistors being each connected to opposite phases (at the fundamental frequency) of a resonator which may comprise of one or more elements, bisected to provide an output tap at which an RF null at the fundamental frequency and an anti-null at the second harmonic exists, whereby the second harmonic output frequency of the push-push oscillator is derived. Particularly when the push-push oscillator operates at microwave frequencies, the resonator element is a microstrip line, having the output tap at the centre thereof.

Abstract: A radar module includes a high-frequency signal generator comprising upper and lower parallel conductive plates, at least one dielectric rod held between the parallel conductive plates, a metal diode mount held between the parallel conductive plates, a gunn diode member mounted on a side of the diode mount, and a printed-circuit board mounted on the side of the diode mount in covering relationship to the gunn diode member and having a bias supply circuit on its surface for supplying a bias voltage to the gunn diode member. One terminal of the gunn diode member extends through a through hole defined in the printed-circuit board, is exposed in the vicinity of the surface of the diode mount, and is connected to the bias supply circuit.

Abstract: A high-frequency signal generator has upper and lower conductive plates parallel to each other, at least one dielectric rod held between the upper and lower conductive plates, a metal mount sandwiched between the upper and lower conductive plates, a oscillating element mounted on a side of the mount for generating a high-frequency signal, a printed-circuit board mounted on the side of the mount and including a bias supply circuit disposed on a surface thereof for supplying a bias voltage to the oscillating element to enable the oscillating element to generate a high-frequency signal, and a positional displacement preventing structure on at least one of the upper and lower conductive plates for preventing the mount from being positionally displaced with respect to the dielectric rod. The positional displacement preventing structure may comprise a groove defined in at least one of the upper and lower conductive plates, the mount being partly fitted in the groove.

Abstract: An electron beam microwave device having an evacuated interaction chamber to which are coupled a resonant cavity which has an opening between the resonant cavity and the evacuated interaction chamber and an electron gun which causes a narrow beam of electrons to traverse the evacuated interaction chamber. The device also contains a mechanism for feeding back a microwave electromagnetic field from the resonant cavity to the evacuated interaction chamber in such a way as to modulate the direction of propagation of the electron beam, thereby further amplifying the microwave electromagnetic field. Furthermore, provision is made for coupling the electromagnetic field out of the electron beam microwave device.

Abstract: In a voltage controlled oscillator, a dielectric resonator is mounted on a circuit board and a metal case is mounted on the circuit board to shield the dielectric resonator. The dielectric resonator comprises a C-shaped first electrode which is provided in a dielectric body, second and third electrodes which are arranged on upper and lower sides of the first electrode, a signal connecting pattern which is extended from the first electrode toward a side surface of the dielectric body, and earth connecting patterns which are extended from the first, second and third electrodes toward the side surface of the dielectric body, to provide predetermined impedance between the earth connecting pattern and the signal connecting pattern. The dielectric resonator is arranged with the second and third electrodes in parallel with a major surface of the circuit board, and the second electrode is upwardly exposed.

Abstract: A shielded microstrip assembly (100)includes a substrate 102 having a first ground plane surface (106) and a second surface (206) which includes a transmission line (216). A plurality of solder balls (104) provide electrical interconnection for the ground plane and for the terminals (210) and (212) of transmission line (216). The microstrip assembly (100) is then inverted and attached using solder balls (104) to a carrier (302). The inverted microstrip assembly (100) of the present invention provides for improved shielding, while maintaining the high Q and other advantages associated with a microstrip.

Abstract: A dielectric resonator device includes an enclosure having a bottom wall, a pedestal made of quartz seated inside the enclosure on the bottom wall, a dielectric resonator element seated on the pedestal, a bracket made of quartz for holding the dielectric resonator down on the pedestal and a clamping disc and screws for securing the bracket to the bottom wall.

Abstract: A microwave oscillator circuit is provided for decreasing the number of passive elements such as inductance, etc. in microwave oscillators and frequency doublers. A microwave oscillator circuit is connected to a resonator circuit generating a signal at a frequency f, and produces at its output a signal of frequency nf, and comprises a first field effect transistor having a gate connected to the resonator circuit, a second field effect transistor whose source/drain path is connected in series with the source/drain path of the first field effect transistor and a connecting circuit for coupling either the gate or source of the first field effect transistor to the gate of the second field effect transistor. A signal of frequency nf is output at a node corresponding to a connection point between the source of the first field effect transistor and the drain of the second field effect transistor.

Abstract: A thermally compensating microwave cavity is provided. An active device that generates microwaves is disposed within this microwave cavity such that microwaves are emitted within the cavity. A first portion of these microwaves travels in one direction from the active device and forms a broad bandwidth signal. A section portion of the microwaves travels toward a reflecting member and is reflected. Once reflected, this second portion combines with and compensates the first portion. A temperature dependent bellows is utilized to displace the active device and the reflecting member relative to one another. Accordingly, as the signal emitted by the active device changes with temperature, the reflecting member is displaced by the bellows to properly reflect the second portion of the microwaves such that it combines with and properly compensates the signal.

Abstract: An array of unit oscillators interconnected with one another in that the transistors of the oscillators are connected to common lines. Separate lines in proximity provide coupling capacitance for feedback to sustain the oscillation of the unit oscillators. The separate lines also form a grid which results in an antenna for emanation of the oscillators, radiation The array can effectively function at extremely high frequencies (i.e., greater than 30 GHz). The array is specially designed to accommodate monolithic implementation.

Abstract: A remote temperature sensor includes a microwave oscillator which generates n output signal having a frequency which is proportional to the temperature of the environment in which it is located. The oscillator includes a relatively high transition temperature superconducting (HTSC) ring coupled to a transistor in a plurality of microstrip line oscillator configurations including those of a reaction oscillator, a transmission oscillator, a reflection oscillator and a parallel feedback oscillator. The superconducting ring operates below its transition temperature and in so doing, acts as a high Q resonator whose resonant frequency is proportional to temperature.

Abstract: A hyperfrequency generator comprising a source element (5) of negative resistance adjacent to a cylindrical resonant cavity (2) closed at opposite ends by two transversal closure plates (4, 7) for the purpose of tuning over a frequency band. The source element (5) is installed directly in the resonant cavity (2) such that there is a direct coupling between the source element (5) and the resonant cavity (2). One of the closure plates (7) is movable toward and away from the other for rough tuning.

Abstract: An arrangement for coupling microwave energy with a reaction chamber, including electrically stable tuning and being, within limits, tolerant against changes in critical dimensions and power fluctuations. A coaxial line between a hollow waveguide and the reaction chamber is of such a structure that it forms, at least together with the reaction chamber, a loss resonator for the microwave frequency employed. The coaxial line can comprise an absorber or, alternatively, can be made of a poorly conductive material. There is also the possibility of downgrading the quality of the resonator by leaving an annular gap between a metal plate and an outer conductor section.

Abstract: In addition to a first opening (11) forming a primary output from a waveguide cavity (10) of a microwave oscillator, a coupling aperture (12) in a reflective wall (32) provides a secondary output which does not degrade the performance or tuning characteristics of the source. Less than -20 dB of the source power may be coupled out via the aperture (12) and is used in a feed-back loop (12,21,23,24,36) with an harmonic mixer (21) and frequency discriminator (24) to stabilize the source. The mixer comprises a further waveguide section (15) separated from the source cavity (10) by the reflective wall (32). An advantageous mixer assembly comprises a circuit substrate which is mounted across the further waveguide cavity (15) and which carries an inductive probe by which the signal from the coupling aperture (12) is fed to an antiparallel pair of mixer diodes on the substrate. The whole assembly may be bolted together through holes (34).

Abstract: A power coupler that is held in place at two different points along its length to substantially eliminate any movement thereof due to vibration of the environment. One of these holding means comprises a piece of dielectric which snugly encloses the coupler to prevent side-to-side movement while still allowing a vertical adjustment of the coupler element through the holding means. A constant impedance equal to that of an electrically connected circuit is maintained along a portion of the coupler by varying passageway opening sizes. The electrical connection to the circuit, which has a threaded terminal comprising a part of the adjustment means and the other holding means eliminates connector insertion loss and signal reflections inherent in prior art signal interfaces between the coupler and an electrical signal receiving circuit.

Abstract: The oscillating apparatus according to this invention includes a pulse doped FET 1, and a series feedback capacitor 2 connected to the source of the pulse doped FET 1. The pulse doped FET is a FET formed on a pulse doped epitaxial layer including a channel layer 23 with a high carrier density, and a cap layer 24 with a low carrier density formed on the channel layer 23. The series feedback capacitor 2 is a variable capacitor whose capacitance value increases when a gate bias voltage of the pulse doped FET 1 is changed to increase a drain current of the pulse doped FET 1. Consequently it is possible to reduce phase noises by controlling only the gate bias with an oscillation frequency set at a required value. As a result, the merits of the MMIC can be sufficiently utilized without the necessity of externally adding a dielectric resonator.

Abstract: A resonator (50) is connected in circuit with a negative resistance element (Q3,Q4) for producing oscillation at a resonant frequency of the resonator (50). A digital phase shifter (58) is incorporated into the resonant frequency in accordance with an applied digital signal. The resonator (50) can be connected in series with the negative resistance element (Q3), in which case the phase shifter (58) is connected as either a short-circuit or an open-circuit transmission line. Alternatively, the resonator (50) can be connected in parallel with the negative resistance element (Q4) in a feedback loop. An analog phase shifter (84) can also be provided in the resonator (50') for continuously variably setting the resonant frequency over the tuning increments of the digital phase shifter (58).

Abstract: There is disclosed a device for fabricating an oscillating apparatus by mounting a dielectric resonator on a substrate having a previously-mounted oscillating unit and a previously-provided microstrip line connected to the oscillating unit for supplying oscillation outputs. The device includes a support element for supporting the dielectric resonator, a positioning mechanism for moving the dielectric resonator to a position with respect to the substrate, a monitoring element for monitoring an oscillation output from the oscillating unit and a control element for controlling a drive element of the positioning mechanism in accordance with an output from the monitoring means.

Abstract: A dielectric resonator oscillator having a resonant structure connected to an amplifier the output of which is fed back to the input of the resonant structure. The resonant structure includes a metal cavity in which a dielectric disk is centrally mounted by a low-loss dielectric post. A pair of microstrip transmission lines extend into the cavity to provide energy outputs and inputs. Dielectric and conductive tuning screws are mounted on the cavity walls. Electrical tuning is provided via a varactor diode whose bias is adjustable. The diode may be connected in series or parallel with the microstrip transmission line.

Abstract: A voltage controlled oscillator having a resonator wherein a substrate is made up of a plurality of dielectric layers; an inductor functioning conductive film and grounding electrode films are each formed at a boundary surface of one of the dielectric layers; the earth electrode films are arranged, in the direction in which the dielectric layers are laminated, at both sides of the conductor functioning conductive film; the inductor functioning conductive film and the grounding electrode films constitute the resonator; and electric lands are formed on the surface of the substrate so that other components of the oscillator are mounted on the surface of the substrate.

Abstract: A microwave oscillator includes a metal housing which defines a cavity in which microwave radiation is produced by an internally mounted Gunn diode or the like. A tuning member projects into the microwave cavity through a hole formed in a wall of the oscillator housing. Depending on the length of its projection into the cavity, the tuning member controls the frequency of the microwave energy produced by the oscillator. The tuning member is supported on the cavity housing by a mounting member made from a material having a relatively high coefficient of thermal expansion. Particularly preferred materials include polymers such as polyethylene and polypropylene. Preferably, a microwave filter or choke is provided to reduce the leakage of microwave energy from the cavity through the hole in the oscillator housing. Such a choke comprises a pair of capacitors separated by an inductor.

Abstract: A conducting plane resonator (10) is used to stabilize an oscillating means (12) typically operating at microwave frequencies. The conducting plane resonator (10) is in proximity to the oscillating means (12) and is magnetically coupled thereto. In a first implementation, the conducting plane resonator (10) is magnetically coupled to an input conductor (16) of the oscillating means (12). In a second implementation, the conducting plane resonator (10) is magnetically coupled to an output conductor (18), which is coupled to the oscillating means (12). In a third implementation, the conducting plane resonator (10) is magnetically coupled to both the input conductor (16) and the output conductor (18). The conducting plane resonator (10) preferably comprises a thin, substantially planar conducting plane and is dimensioned such that it is resonant at the desired operating frequency. The conducting plane resonator (10) is preferably fabricated of a superconductor material to achieve high-Q performance.

Abstract: YIG oscillator apparatus comprises both an FET-based YIG oscillator circuit and a bipolar transistor-based YIG oscillator circuit inside a single magnetic structure. Both YIG spheres are disposed in the single air gap of the magnetic structure, which is defined by a pole piece which is tapered to an elongated pole surface which is only slightly larger than necessary to cover both YIG spheres. A band reject filter is included inside the housing for rejecting second harmonics of desired oscillation frequencies only.

Abstract: An embodiment of the present invention is a voltage controlled oscillator (VCO) comprised of a differential pair of transistors that have respective positive feedback paths with phase-lead networks cross-coupled. Each positive feedback path on each side has two different phase-lead branches. The two phase-lead branches have the same phase differences on each side of the differential pair, in order to maintain a symmetry that improves common-mode noise rejection on a voltage control differential input. Current-steering is used to control the mixture of currents that arrive at the bases of the differential transistor pair from the respective two different phase-lead branches, and thereby changing the frequency of the VCO.

Abstract: A source for generating energy in the microwave region to a load comprising a transmission line, a semiconductor switch connected between said transmission and said load, said switch being operable, in its open state, to sustain a voltage corresponding to the average maximum electric field physically sustainable by the switch and, in its closed state, to sustain the maximum current density J equal to Wd.sub.3, where W is the width of the switch and d.sub.3 its thickness to thereby supply maximum power to the load and maximum switching speed.

Abstract: In a plasma generator for high-frequency supply of an induction coil containing a plasma of an aerosol with a substance to be analyzed, quarter-wave conductors of a quarter-wave resonant system are incorporated in the apparatus after having been divided and folded, which provides a significant saving in space. Added to the conductors are electric auxiliary circuitry for balancing the resonant system and for matching the frequency to a filled induction coil. The conduction coil is capable of up and down movement in a disturbance-free manner, the coil always being maintained at zero potential.

Abstract: In an oscillator employing a triplate type stripline, earth (ground) electrodes are formed only on an opposite pair of side surfaces of a substrate in which the stripline is embedded. An oscillation circuit mounted on the substrate is covered with a shielding case and the remaining side surfaces of the substrate, which are provided with no earth electrodes, are covered with shielding plates which are provided on the shielding case. Connecting portions of the shielding case are electrically connected with the earth electrodes by soldering. Thus, the stripline is electromagnetically shielded in a simple manner so that it is possible to easily manufacture an oscillator employing a stripline at a low cost.

Abstract: A low-noise oscillator has a resonant circuit for generating a signal at a desired frequency. A linear amplifier and a limiter are electrically connected to the resonant circuit at first, second and third locations. A buffer amplifier is electrically connected to the resonant circuit at a fourth location and applies the signal generated by the resonant circuit to a load. The first, second, third and fourth locations are selected to minimize the impedance from those locations to ground at 1/f frequencies.

Abstract: Structure for use in forming a resonant circuit eliminates a support block for the installation of a dielectric resonator, by providing a satisfactory way to directly install the dielectric resonator on a microwave circuit board having a microstrip line. The dielectric resonator is directly fixed on the microwave circuit board in such a manner that mutually opposing planar surfaces thereof do not face one planar surface of the microwave circuit board, and an axial line passing normally through these planar surfaces intersects a normal plane projected from the microstrip line. As a result, production costs can be reduced and simplified work processes can be used to fabricate the structure. Further, an electrode film may be formed on a flat part of the outer periphery of the dielectric resonator, and such a dielectric resonator is fixed on the microwave circuit board with the flat part on which said electrode film is formed, facing upwards.

Abstract: A monolithic microwave IC oscillator includes a feedback amplifier having a field effect transistor and a varactor diode. The varactor diode has a junction capacitance that varies according to the bias voltage applied to said diode and capacitively couples the amplifier to an external load. Any variation of the capacitance of the load-coupling capacitor caused by design errors or by variations in the manufacturing process can be easily corrected when the device is used. As a consequence, the oscillator can always be operated with good oscillaitng characteristics without hindering integration of individual components and without increasing costs.

Abstract: A voltage-controlled oscillator using planar microstrip technology and primarily for the 37 to 39.5 GHz frequency band comprises a strip-line resonator, a negative resistance device mounted adjacent the center of the resonator, respective variable capacitance devices mounted adjacent the ends of the resonator, a high impedance coupling the resonator to an output path, and bias signals are applied to the negative resistance device and said variable capacitance devices.

Abstract: An oscillator includes an amplifier having an input and an output and a feedback circuit disposed between the input and the output of the amplifier. The feedback circuit includes a plurality of resonators and a pair of switches. Each switch includes a first port and multiple connectable ports, the multiple connectable ports of each switch connected to a corresponding one of the plurality of resonators. The feedback circuit further includes a voltage-controlled phase shifter disposed in series with the switches. The oscillator further includes a discriminator circuit, responsive to signals from the feedback circuit, for providing a control signal to the voltage-controlled phase shifter for degenerating low frequency noise within the oscillator. With such an arrangement, high Q low noise resonators can be switched in and out of the circuit thus providing improved phase noise performance at high power levels with the desirable frequency agility required for a microwave oscillator.

Abstract: A Q enhanced dielectric resonator circuit includes a metal enclosure having interior walls defining a chamber. Secured to at least two interior walls is a dielectric substrate. Flatly mounted to at least one side of the dielectric substrate is a substrate stripline. A dielectric resonator is secured to the dielectric substrate at a selected distance from the substrate stripline. The dielectric substrate is positioned a sufficient distance from a ground plane such that the magnetic field lines of the dielectric resonator do not significantly interact with the ground plane. The dielectric resonator is also positioned such that there is substantial coupling of the magnetic field lines of the dielectric resonator with the magnetic field lines of the substrate stripline.

Abstract: A broadband, varactor-tuned shorted coax resonator is provided with a single point coupling port that facilitates coupling of discrete circuitry to the distributed resonator to form an oscillator. The coupling port is defined by adding a second shorted coax line across the end of the first. The outer conductors of the two lines are interconnected. The inner conductors of the two lines are serially coupled and define a coupling gap, either along their length or at their ends, across which discrete circuitry can be connected. In a preferred form of the invention, the discrete circuitry is positioned in a region within the periphery of one of the inner conductors in order to provide an electromagnetic shield for the circuitry.

Abstract: A W-band waveguide variable controlled oscillator incorporating a capacitively coupled Gunn diode and varactor diode arranged in such a manner that adverse environmental conditions do not deleteriously effect the stability of the output of the oscillator. The Gunn diode is electrically connected to a waveguide chamber within the oscillator and includes a resonator electrically connected to its end cap. The resonator is electrically connected to a DC bias source by means of a DC bias filter and a wire inductor. Opposite and above the Gunn diode is a varactor assembly including a varactor diode, which is also electrically connected to a DC bias source through a DC bias filter. A variable coupling spacer within the varactor assembly adjusts the distance between the varactor diode and the Gunn diode such that the capacitive coupling between the two can be adjusted. In addition, an adjustable back-short is incorporated within the waveguide channel to adjust the power output of the oscillator.

Abstract: A low-noise cryogenic oscillator has a resonant circuit formed of superconducting material for generating a signal at a desired frequency. A linear amplifier and a limiter are electrically connected to the resonant circuit at first, second and third locations. A buffer amplifier is electrically connected to the resonant circuit at a fourth location and applies the signal generated by the resonant circuit to a load. The first, second, third and fourth locations are selected to minimize the impedance from those locations to ground at 1/f frequencies. The resonant circuit, the linear amplifier, the limiter and the buffer amplifier are all maintained at a temperature below the critical temperature of the superconducting material.

Abstract: YIG oscillator apparatus comprises both an FET-based YIG oscillator circuit and a bipolar transistor-based YIG oscillator circuit inside a single magnetic structure. Both YIG spheres are disposed in the single air gap of the magnetic structure, which is defined by a pole piece which is tapered to an elongated pole surface which is only slightly larger than necessary to cover both YIG spheres.

Abstract: A source for generating microwaves using sequential switching of cascaded TEM transmission lines of arbitrary lengths charged to arbitrary voltages where the delay between any two switches is equal to or greater than the temporal length of the transmission line separating them, the first switch activated being the one closest to the load. The source uses an optimized transmission line and switch geometry which yields the highest possible power flow. Various folded configurations of the source which provides added compactness and simplified energizing are also disclosed.

Abstract: A miniature microstrip/cavity oscillator which is mechanically tunable over a wide range of microwave frequencies and maintains high frequency stability over changes in temperature. The oscillator consists of a RF (resonant frequency) determining element, a microstrip circuit board means, and a capacitive coupling probe coupling the microstrip circuit board means to the RF determining element. The RF determining element is constructed of various materials with different coefficients of linear expansion to eliminate expansion and contraction effects due to temperature changes.

Abstract: The microwave oscillation circuit provides a transistor having the collector electrode grounded, the base electrode connected to a resonator circuit determining the oscillation frequency, and the emitter electrode connected to an output open stub. An output transmission line is placed parallel to the output open stub for the output power supplied from the output open stub to be output via an end of the output transmission line to a buffer amplifier. A resistor having an impedance equal to a characteristic impedance of the output transmission line connects a stub circuit to an open end of the output transmission line. The stub circuit exhibits an infinite impedance at the oscillation frequency. At the oscillation frequency, the resistor floats due to the infinite impedance of the stub circuit so that all the oscillation power supplied from the output open stub is output to the buffer amplifier, without being consumed by the resistor.

Abstract: An oscillator operational in the millimeter wave and microwave range, including frequencies greater than 60 GHz, is provided with reduced phase noise by enhancing Q of the resonant circuitry by reactively terminating fundamental frequency oscillation and increasing stored fundamental frequency energy in the resonant circuitry. A two frequency system is provided with constructive reflection of energy at fundamental frequency back to the resonant circuitry, and with isolation of fundamental frequency energy from the output load. Energy to the output load is obtained from the in-situ generated second harmonic of the active element. Phase noise is reduced by enhancing Q by more than an order of magnitude.

Abstract: Apparatus for allowing low noise and fast frequency switching of a ferri-resonant oscillator, such as YIG, that uses a coil to control output signal frequency by current level. The apparatus positions an active filter in parallel with the oscillator coil, which can be set to one of two impedance levels. A low impedance level provides low pass filtering of the current to the oscillator coil for low noise operation. A second high impedance level allows fast settling of transients during frequency changes. Once current levels have stabilized, the active filter can then be switched to low impedance mode without creating a significant transient. This facilitates fast frequency switching.

Abstract: An oscillator comprises a resonator for providing an oscillation frequency for the oscillator, an active network, coupled to the resonator, for driving the resonator, and a split-ring resonator coupled to the main resonator and used to provide amplitude and phase balanced outputs. The split-ring resonator has at least a first edge, which is coupled to the resonator, and a second edge. The second edge has a gap therein, and a first terminal located at one side of the gap, and a second terminal symmetrically located at the other side of the gap.

Abstract: An oscillator providing predictable oscillator modulation sensitivity includes an amplifier and a feedback circuit disposed about the amplifier. The feedback circuit includes a resonator having a first port and a second port and a voltage-controlled phase shifter having an input port, an output port and a control port, the input port of the voltage-controlled phase shifter connected to the output port of the amplifier and the output port of the voltage-controlled phase shifter coupled to a port of the resonator. The oscillator further includes a circuit, responsive to signals from the output of the voltage-controlled phase shifter and the first port of the resonator, to provide a control signal to the control port of the voltage-controlled phase shifter for degenerating low frequency FM noise arising within the amplifier.

Abstract: Flicker (1/f) noise is suppressed in an oscillator by reducing oscillator voltage-frequency pushing to zero. A varactor (56) is incorporated in the resonator circuit and is biased with a tuning voltage setting the varactor to a capacitance value providing the zero oscillator pushing at a given frequency. A common bias connection (62) is provided between the varactor and the active element (64) such that a random perturbation voltage change across the active element also causes a change in voltage across the varactor, to compensate a change in oscillator frequency otherwise caused thereby. The varactor capacitance versus voltage characteristic is shaped such that a change in active element voltage provides a change in varactor voltage, and the combination of these voltage changes results in a zero change in oscillator frequency. The tuning slope of the oscillator provided by the varactor is opposite the tuning slope of the oscillator resulting from a change in active element voltage.