Abstract: An improved method and system for generating quadrature phase shift keying signals for use in data transmission is provided. A pair of oscillators are slaved to the transmit frequency and produce two quadrature signal components with the same frequency but 90 degrees out of phase. The two signal components are carried to separate bi-phase switches by mirrored waveguides. Each bi-phase switch has a reflective waveguide coupler which directs the received signal into a waveguide terminated by a hard short and has a controllable shorting plane spaced approximately one-quarter wavelength from the termination point. The shorting planes are controlled by the output data signals and each introduces a 180 degree phase shift in the respective signal component when activated. The reflective couplers direct the selectively phase shifted signal components to an in-phase combiner, where they are combined to produce the quadrature phase shift keyed output signal.

Abstract: In a thick multilayered wiring board, a coaxial signal wiring pattern is surrounded by upper and lower horizontal grounded conductive layers and vertical grounded conductive layers and the vertical conductive layers of conductive layers which surround the coaxial signal wiring pattern are formed in a photosensitive dielectric layer by a photolithography, whereby matching of characteristic impedance of the pattern is improved and thus crosstalk is reduced.

Abstract: A four-diode bridge is positioned within the cavity of a Gunn diode oscillator. A subharmonic signal is applied to the diode bridge and the diode bridge couples an odd harmonic of the injected signal into the cavity. The cavity is thus caused to resonate at the odd harmonic of the injected signal. The injected signal can be changed using a frequency synthesizer in order to provide a microwave oscillator with multiple-channel operation. The diode bridge provides a feedback signal indicative of the phase of cavity oscillation. The feedback signal is applied to a varactor which pretunes the Gunn diode oscillator and thereby provides phase-locked control.

Abstract: A composite diode module is provided having an impedance matching member integrally formed within the module. The module includes a base member, a heat sink holder member having an aperture, a gold plated diamond heat sink which is disposed in the aforementioned aperture, and an encapsulant holder member having a second aperture. IMPATT diodes are disposed in dielectric spacers bonded to one end of the heat sink in alignment with the second aperture. A bias pin member is then bonded on the second end of the IMPATT and an encapsulant having selected electrical properties is provided in the second pair of apertures to secure the diode and to provide the diode module with a predetermined impedance characteristic. In a preferred embodiment, the module includes a pair of IMPATT diodes. With this arrangement, the module may be used in power combiners.

Abstract: An IMPATT diode mounted in a double-tuned resonant cavity to exhibit stability by suppressing subharmonic frequencies is disclosed. A foreshortened quarter wavelength section is connected to the diode to form an equivalent parallel resonant circuit at one end thereof. At the other end of the quarter wavelength section is an odd-quarter wavelength tuning slug which provides a section which exhibits a second, series equivalent resonant circuit. To provide increased stability at subharmonic frequencies, a half-wavelength tuning slug is disposed adjacent to the odd-quarter wavelength section. The half wave tuning slug is virtually transparent at the operating frequency, but is a quarter-wavelength at the first subharmonic, and thus exhibits a high resistance at the subharmonic frequency.

Abstract: A solid state microwave power combiner is disclosed having a central combining cavity with a plurality of coaxial oscillator circuits disposed about and coupled to the cavity. The oscillator circuits are oriented such that their longitudinal axes are parallel with the central axis of the combining cavity. They alternate in configuration about the cavity such that adjacent oscillator circuits have their power generating diodes located on opposite sides of the cavity. In one embodiment, the coaxial lines used in the oscillator circuits have two parts of different sizes. The oscillator circuits are oriented about the cavity so that the smaller sized coaxial line part of one is adjacent the larger sized coaxial line part of the next. Both rectangular and circular combining cavities are disclosed.

Abstract: A plurality of negative resistance devices is spaced below a cylindrical center conductor of a single coaxial cavity. Each negative resistance device has a bias device connected to it by a bias wire. Extending radially through the outer wall of the coaxial cavity is a coax cable with an RF coupling probe. A tuning screw is place axially through the interior of the center conductor for tuning the frequency of the power combiner.

Abstract: A microwave oscillator suitable for millimeter wavelengths comprises a Gunn diode (3) coupled to a waveguide (1) by a resonant-cap structure (5,6). The diode (3) generates microwave energy both at a fundamental frequency f.sub.o which is below the cut-off frequency of the waveguide (1) and at a second harmonic frequency 2f.sub.o above cut-off. To control the generation of microwave energy at 2f.sub.o, energy at f.sub.o is coupled into the waveguide (1) from an adjacent further waveguide (9) above its cut-off, by means of an electric probe (8) extending close to the cap (5). The probe (8) may couple in a locking signal at or close to the free-running value of f.sub.o from another oscillator having better noise performance and electronic tuning, thereby locking 2f.sub.o to twice the frequency of the locking signal, or alternatively may couple to a varactor-tuned cavity resonant at f.sub.o.

Abstract: In a method of fabrication of a module formed by a semiconductor diode which oscillates in millimeter waves and by a variable-capacitance diode, the oscillating diode is mounted on a pedestal at the center of a support base. A ring of fused silica for supporting a metallic disk of predetermined diameter serves to form a radial space between two metallic surfaces with a view to readily obtaining oscillation in a predetermined frequency band. A similar ring is welded at one end to the opposite face of the disk and at the other end to another metallic base fitted with a central variable-capacitance diode. Flexible connections bonded to the diodes are clamped between the rings and the disk. The module may be incorporated in a tunable oscillator.

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: A wideband VCO including a coaxial cavity with a negative impedance semiconductor diode and a tuning varactor mounted in a center conductor thereof. A variable bias circuit connected to the tuning varactor for tuning the VCO through a predetermined range. An output probe including a coupling varactor in contact with the center conductor. The variable bias circuit is coupled to the coupling varactor to alter the output coupling capacity as the frequency of the oscillator changes so that the output power remains substantially constant.

Abstract: An improved combiner of microwave power out of a plurality of coaxial diode oscillators is shown to be made up of a circular cylindrical cavity dimensioned to operate in the TM.sub.020 mode at a selected microwave frequency, with such oscillators being disposed about the periphery of both end planes of such cavity and each individual one of such oscillators being reentrant at an angle of 180.degree. so as to double the number of such oscillators as compared with the number of straight coaxial diode oscillators that may be disposed about the periphery of such cavity.

Abstract: A power combiner using a circularly cylindrical cavity, dimensioned to support the TM.sub.020 mode, to combine the power from coaxial diode oscillators is shown to comprise: (a) a first plurality of such oscillators disposed about the periphery of such cavity; (b) a second plurality of such oscillators disposed in coincidence with the first spatial null in the electric field in such cavity; and (c) a plurality, similar in number to the second plurality of such oscillators, of electrically conductive bridges interposed between the top and bottom walls of the cavity in-between the center conductors of the coaxial diode oscillators in the second plurlaity of such oscillators.

Abstract: A time-delay triggered TRAPATT oscillator in which the delay line impedance progressively increases from the diode end to a trigger element. Thus, all reflections except those from the trigger element are negative-going and help to reduce the rise in diode voltage between trigger pulses.

Abstract: An efficient higher order mode resonant combiner in which a higher order mode accumulator cavity is adjusted to have the real part of its input characteristic impedance to be so minimized as to be less than the characteristic impedance Z.sub.o of the input circuit. When an active device is matched to this low, minimized value of cavity input impedance a mismatch results between the active device power source and the input to the combiner at undesired higher order modal frequencies. This resultant mismatch at undesired modal resonances obviates the need for mode suppression devices within the cavity which devices as taught in the prior art had detrimental effect of the efficiency of the combiner.

Abstract: A microwave oscillator/amplifier includes a plurality of TEM transmission lines each with a negative resistance device at one end and a lossy, matched termination at the other end. A resonant cavity is coupled to each TEM line so as to induce a parallel resonance on the lines at the region of coupling. Structural means are provided for maintaining the characteristic impedance of the TEM lines uniform along the length of said lines. Fabrication of a device in which the TEM line characteristic impedance was uniformly maintained along the line length at five times the optimum negative resistance of said negative resistance device is noted. Suggested levels of characteristic impedance are relatively low compared to prior art devices, none of which are known to attempt maintenance of characteristic impedance uniform along the length of the TEM transmission line.

Abstract: A coaxial cavity resonator comprising an outer conductor and an inner conductor coaxially disposed in the outer conductor with one end of the inner conductor being connected to an end wall of the outer conductor to establish a short-circuit relationship and the other end of the inner conductor being spaced from the other end wall of the outer conductor to establish an open-circuit relationship. An intermediate hollow conductor is disposed coaxially with the inner and outer conductors and encircles a portion of the axial dimension of the inner conductor. The intermediate conductor has a closed end which is connected with the open-circuit end of the inner conductor.

Abstract: A microwave combiner assembly is described incorporating a coaxial transmission line having a plurality of diodes exhibiting negative resistance at high frequency mounted between the center conductor and the outer conductor of the transmission line. Each diode is mounted on a segment forming a portion of the center conductor which are separated by slots containing lossy dielectric. A signal is capacitively coupled from each diode by capacitively coupling each segment to a common center conductor. Each diode is biased by coupling a bias voltage to each segment. The microwave combiner overcomes the problem of mechanically assembling a plurality of diodes in an oscillator or amplifier while attenuating anti-phase currents in the diodes indicative of undesired oscillator modes.

Abstract: A microwave power combiner is shown to consist of a plurality of coaxial diode oscillators disposed on the periphery of a circularly cylindrical cavity operating in the TM.sub.020 mode, such cavity containing mode suppressor means to prevent any mode other than the TM.sub.020 from operating.