Abstract: An improved solid state transmitter (and elements therefor) adapted particularly well to pulsed operation at radio frequencies is disclosed. Such transmitter includes the combination of: A crystal-controlled oscillator producing a continuous wave output signal which, ultimately, determines the frequency of each transmitted pulse; a first oscillatory circuit, including a resonant cavity and at least one normally quiescent coaxial oscillator incorporating an IMPATT diode; a second oscillatory circuit, including a resonant cavity and a plurality of normally quiescent coaxial oscillators, each one of such oscillators incorporating an IMPATT diode; and an improved modulator for periodically actuating all of the IMPATT diodes in such a manner that a pulsed output of the first oscillatory circuit is produced which remains locked to the then existing continuous wave signal out of the crystal-controlled oscillator and the pulsed outputs of the coaxial oscillators in the second oscillatory circuit similarly are locked.

Abstract: An adjustable feedback in a pencil tube oscillator is provided by a pick-up element closely spaced from the center conductor of the output cavity of the oscillator with the pick-up element connected via a short length of rigid conductive wire to the cathode electrode in the input cavity. This pick-up element is a thin sheet of deformable conductive material fixed to the end of the rigid wire in a manner that permits the sheet to be easily bent toward or away from the center conductor to accommodate adjustment of the feedback coupling capacitance.

Abstract: An accumulating cavity microwave oscillator having a plurality of coaxial circuit mounted negative resistance diodes coupled to the cavity wherein the plurality of coaxial circuits may be mounted in concentric circles or in other symmetrical or non-symmetrical configurations and one or more coupling mechanism outputs may be utilized. No output is required to be located at the center of either the accumulator or the auxiliary cavity thereby allowing cavity tuners to be mounted there. The coupling coefficient in the coaxial circuits is equal to one plus the coupling coefficient of the output probes in order to present a relatively constant load to the diodes over the operating frequency range, thereby maximizing the usable operating frequency range.

Abstract: A circuit for microwave oscillators or amplifiers, yielding the maximum microwave power from negative resistance diodes feeding into one and the same waveguide section. Diodes are arranged in pairs symmetrically at the level of one and the same right section of the waveguide but outside the waveguide cavity. In the case where two diodes are used, these are screwed into clamps arranged in chambers opening into the cavity. Cylinders effect impedance matching between waveguides and diodes and are supported mechanically by a shaft which supplies the direct voltage for the circuit.

Abstract: A housing defining a first cavity forming a transmission line and a negative impedance semiconductor device terminating one end of the transmission line in a negative impedance, the housing further defining a second cavity resonant at a predetermined frequency and a means of electromagnetically coupling between the transmission line and the second cavity to couple energy therebetween, a reactive element formed between said negative impedance semiconductor device and the housing to provide a shunt susceptance to parallel resonate with the susceptance of the semiconductor device at the desired frequency and bias, and load isolator connected to the opposite end of the transmission line for transmitting RF output pulses to the RF load and for applying a DC bias thereto normally at a first level and periodically reduced to a second level for a short duration, said semiconductor device operating as a series resonant circuit with the DC bias at the first level to cause energy to be stored in the resonant cavity and

Abstract: A receiver module including a mode launcher, a band pass filter, a local oscillator and a balanced mixer for use in the frequency range 1 GHz to 1,000 GHz, wherein the components are all connected by an insular waveguide transmission line having a conductive image plane, a dielectric waveguide attached to the image plane by a thin film of plastic, the thin film being low loss in character and having a low permittivity compared with that of the dielectric waveguide, the ratio between the thickness of the thin film and the square root of the cross-sectional area of the dielectric waveguide being in the range from about 0.02 to about 1.0.

Abstract: A high power, pulsed microwave frequency converter for a microwave communications system including a phase locked loop with a voltage controlled microwave oscillator that provides at least five watts of pulsed RF output power, the components of the loop being designed to lock on the desired RF output frequency within approximately 20 nanoseconds or during the initial portion of each pulse so that the converter coherently converts two low level signals, one or both of which may be pulsed, into a higher level narrow pulse signal at the sum or difference of the frequencies of the two low level signals.

Abstract: A radio frequency oscillator having an improved varactor mounting structure and tuning slug mounting arrangement is disclosed. The varactor mounting structure includes a coaxial transmission line, one end of the center conductor thereof being capacitively coupled to the cavity of the oscillator and the other end being coupled to the varactor. The length of the center conductor is .lambda./2 where .lambda. is the nominal operating wavelength of the oscillator and hence, while disposed outside the cavity, such varactor appears, electrically, within the cavity. A feed wire for coupling a direct current control signal to the varactor is connected between the housing of the oscillator and the center conductor at a point .lambda./4 from the capacitively coupled end of the center conductor. Therefore, while such wire enables direct current to pass between the housing and the varactor, such wire is electrically isolated from the radio frequency energy in the cavity.

Abstract: An improvement in a prior art microwave diode coaxial oscillator circuit comprising an unloaded fundamental frequency cavity for prevention of energy loss in the matching termination at the resonant frequency of the circuit and a second harmonic resonant cavity for controlling second harmonic loading of the diode and for reducing noise in the output signal.

Abstract: A microwave oscillator using a transit-time transistor structure with a space charge zone, is provided. The negative resistance introduced by the transit-time in the space charge zone is utilized in a circuit connected with emitter and collector, the base being direct-biased and not passing the high frequency. To avoid a short-circuiting by the parasitic base-collector capacitance, a transmission line is connected in parallel across the base and collector terminals. The input impedance of this line is adjusted by short-circuiting this line at a distance close to a quarter of wavelength, thus creating an input inductance able to compensate the effect of the base-collector capacitance.

Abstract: The dual cavity oscillator includes a pair of electromagnetically coupled resonators and a limited space charge accumulation (LSA) device disposed in one of the resonators. The resonators form a parallel resonance circuit at a first frequency and the LSA device and the pair of resonators form a series resonance circuit when the oscillator is operated at a second frequency which is generally within a few percent below the first frequency.

Abstract: A Transverse Electromagnetic Field (TEM) transmission line or lines with a negative impedance semiconductor device at one end and a lossy radio frequency (RF) load impedance at the other end, a TEM resonant transmission line with output power coupled therefrom, and an opening for coupling energy from the TEM transmission line or lines to the TEM resonant transmission line at the desired frequency with the Q of the oscillator being determined by the amount of coupling provided.

Abstract: A temperature compensated cavity oscillator comprising a resonant coaxial cavity of which the outer conductor is constructed of dissimilar materials. The end walls and adjacent portion of the outer conductor of the coaxial cavity are made of a first conductive material having a first temperature coefficient of expansion. Interposed between the first conductive material of the outer conductor, the middle portion of the outer conductor is made from a second conductive material having a second temperature coefficient of expansion. A tuning rod is displaced through the middle portion of the cavity and capacitively coupled to a center coaxial conductor to provide mechanical tuning of the oscillation frequency and for varying the frequency of the cavity with temperature such that the temperature characteristics of the oscillating element are compensated to produce a substantially stable oscillating frequency.

Abstract: A microwave oscillation device of the invention comprises a cut-off waveguide having a cut-off characteristic with respect to a frequency used. At one end of this cut-off waveguide is provided a coaxial line member, at one end of which is provided a microwave absorber and at the other end of which is disposed an oscillation element. Within said cut-off waveguide is disposed a dielectric resonator so as to be electromagnetically coupled to the oscillation element of the coaxial line member in terms of lumped constant and to an output waveguide provided at the other end of the cut-off waveguide in terms of distributed constant.

Abstract: A microwave power generator comprises a cavity resonator and at least two oscillators built using transmission lines and negative resistance diodes, magnetically coupled to the resonator. At least one additional oscillator is added and electrically coupled to the resonator at a point where the electric field is at a maximum, increasing the volumetric power delivered by the generator, by 50%.

Abstract: A two-inductor varactor tunable solid-state microwave oscillator comprising a series tunable circuit wherein one inductor is serially connected with a negative resistance active element, an impedance load, and a varactor. The circuit is tuned by changing the reactance of the circuit by varying electrically the capacitance of the varactor. The second inductor is connected in parallel with the varactor to increase the range of reactance change of the series circuit effected by the variation in capacitance of the varactor to provide thereby for a wider frequency tuning range.

Abstract: Two embodiments are disclosed of a system for the fast tuning of high power amplifier circuits. In one embodiment a strip line resonating circuit is selectively tuned by the actuation of selected ones of a plurality of PIN diodes which interconnect a relatively high impedance of strip line circuit with a strip line circuit having a lower characteristic impedance. In the second embodiment a coaxial cavity is terminated in an output transmission line. The cavity and the output transmission line are separated by an array of shorting stubs, each of which is selectively energizable by a suitably located PIN diode.

Abstract: Novel apparatus is provided which permits the combination of the peak pulse power from a pair of avalanche diode oscillators, each diode driving a respective one of two symmetrically suspended airstrip transmission lines which are coupled to a common output connector.

Abstract: Novel apparatus is provided which permits the additive combination of the peak pulse power from multiple avalanche diodes operating in the IMPATT mode without spurious signal generation and includes the use of radially disposed combinations of avalanche diodes and coaxial transmission line resonators feeding a common signal output coupler.

Abstract: Disclosed is a microwave power accumulator including a plurality of coaxial oscillator circuits, each tightly coupled to a single common output combining resonant cavity. Each of the coaxial circuits includes a negative resistance diode at one end and a lossy terminating (microwave absorbing) material at the other end which absorbs and suppresses resonant modes within each coaxial circuit. This feature enables the cavity resonance of the common output combining cavity to dominate all of the individual coaxial circuits spaced therearound. The spacing of these coaxial circuit modules around a common cylindrical output combining cavity permits a high packing density and good individual heat sinking for the accumulator.