Abstract: A two-stage RF amplifier comprising first and second transistors arranged in cascode. An input stage includes a common source transistor having a gate terminal responsive to an input signal and an output stage includes a common gate transistor having a source terminal operatively connected to the drain terminal of the common source transistor. A shunt feedback network is arranged between a drain terminal of the common gate transistor and the gate terminal of the common source transistor. A source feedback network is arranged between the source terminal of the common source transistor and a reference potential. A common gate feedback network is arranged between the drain terminal of the common gate transistor and a gate terminal of the common gate transistor. And a termination feedback network is arranged in series between the reference potential and the gate terminal of the common gate transistor.

Abstract: A dual polarization antenna for transmitting/receiving polarized radio frequency signals includes a reflector plate that reflects the polarized radio frequency signals and one or more dipole assemblies. Each dipole assembly has two cross bow tie dipoles having radiating arms for transmitting/receiving the polarized radio frequency energy signals at two polarizations, and having U-shaped air-filled transmission feedlines for supporting respective radiating arms and providing the radio frequency signals between the reflector plate and the respective radiating arms. Each U-shaped air-filled transmission feedline includes two legs and respective feed rods arranged in respective legs. Each leg has a rectangular shape with three sides for isolating undesirable radio frequency energy. The radiating arms are triangularly-shaped and have notches dimensioned for minimizing radiation pattern distortion due to undesirable radio frequency coupling between the two cross bow tie dipoles.

Abstract: A composite structure including stacked layers of dielectric material hav a center conductor in the form of a cylindrical via which is surrounded by an annular dielectric region and an outer ground plane comprised of contiguous pairs of generally circular ground plane segments where each pair of ground plane segments are separated by a pair of spaces or gaps therebetween and wherein the gaps of adjoining layers are mutually oriented by a predetermined angle of rotation, preferably 90.degree..

Abstract: A composite structure including stacked layers of dielectric material hav a center conductor in the form of a cylindrical via which is surrounded by an annular dielectric region and an outer ground plane comprised of contiguous pairs of generally circular ground plane segments where each pair of ground plane segments are separated by a pair of spaces or gaps therebetween and wherein the gaps of adjoining layers are mutually oriented by a predetermined angle of rotation, preferably 90.degree..

Abstract: An optically controlled MESFET semiconductor oscillator assembly having a MESFET semiconductor which, when voltage biased by a pulsed dc voltage, oscillates at a free running frequency; an optical signal delivery system, such as a light intensity modulator connected to optical fibers; and other oscillator circuitry including a pulse generator. In operation, the pulsed free running oscillation of the MESFET semiconductor can be injection locked to the intensity modulated optical signal delivered via the optical signal delivery system.

Abstract: A dual-gate self-oscillating mixer FET that is injection-locked from a remote LO frequency source. The dual-gate FET having a feedback circuit connected between the first gate port and the drain port that is tuned so that the FET can oscillate within a frequency range including a predetermined LO frequency. The FET having a remote synchronization circuit electrically connected to the FET first gate port to inject the predetermined LO frequency therein and lock the FET oscillation to that LO. Accordingly, the dual-gate FET mixes RF energy input to the second gate port with the locked LO injected in the first gate port and outputs the desired intermediate frequency through the drain port.

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 coupling of optical signals to the active region of a FET having a wide source to drain spacing via an optical fiber and material having an index of refraction matching that of the fiber or the FET so as to increase the locking range when the FET is part of an oscillator circuit or to increase the change in the electrical gain of the FET caused by a change in the optical energy if the FET is an amplifier.

Abstract: An optically controlled oscillator circuit having an oscillator field eff transistor (FET) and having a separate light sensing quench FET. The optically controlled oscillator circuit includes, a light source, a control connected to the light source, an optic fiber having an end coupled to the light source, a quench field effect transistor (FET) coupled to a second end of the optic fiber, an oscillator FET, each FET being a GaAs multi-finger FET having drains and sources and gates, and a circuit connected in series circuit through the drains and sources of the quench FET and oscillator FET across a source of positive voltage.

Abstract: A fundamental or subharmonic optically injection locked oscillator is coupled to a phase locked loop circuit. The injection locked oscillator has two single stage HEMT amplifiers with parallel feedback from the drain of a second transistor to a gate of a first transistor. A feedback resonant network controls the oscillator frequency. A microwave/millimeter wave source modulates a laser diode and the signal from the laser diode is then transmitted via an optical fiber to a PIN photodetector diode. The signal from the photodetector diode is injected into the oscillator at an nth subharmonic of the oscillator frequency. The feedback network may consist of a microstrip gap resonator with two tuning varactors at the ends of the resonator. The phase locked loop includes a balanced mixer used as a phase detector to compare the nth harmonic of the signal from the photodetector diode to the sampled output of the oscillator.

Abstract: A needle scaling device for environmentally safe removal of material such as lead paint or the like, from difficult to clean surfaces, such as bridges. The needle scaling device includes a plurality of reciprocably movable needles which strike the surface being treated, to chip away the paint. A cowling is disposed about the distal end of the device to enshroud the needles. The cowling has an annular array of bristles disposed on its distal end, to provide a flexible shroud and hence a containment plenum around the needles.

Abstract: An optically controlled resonant tunnel diode oscillator assembly having a esonant tunnel diode (RTD) which, when voltage biased, oscillates at a free running frequency; an optical signal delivery system, such as a light intensity modulator connected to optical fibers; and other oscillator circuitry which one skilled in the art could readily adapt to the concepts of the present invention. In operation, the free running oscillation of the RTD can be frequency modulated or can be intensity locked to the intensity modulated optical signal delivered via the optical signal delivery system.

Abstract: An optical controlled attenuator circuit for controlling a microwave varie attenuator. The optical controlled attenuator circuit includes, a light source, a control connected to the light source, an optic fiber having an end coupled to the light source, a field effect transistor coupled to a second end of the optic fiber, a first inverting amplifier coupled to the field effect transistor, a second non-inverting amplifier coupled to the first amplifier means, a third non-inverting amplifier coupled to the second amplifier, a fourth inverting amplifier means also coupled to the second amplifier, and a microwave variable attenuator having first and second inputs respectively coupled to the fourth inverting amplifier and to the third non-inverting amplifier means and having an RF input and an RF output.

Abstract: An optically injection locked resonant tunnel diode oscillator assembly hng a resonant tunnel diode (RTD) which, when voltage biased, oscillates at a free running frequency; an optical signal delivery system, such as a light intensity modulator connected to optical fibers; and other oscillator circuitry which one skilled in the art could readily adapt to the concepts of the present invention. In operation, the free running oscillation of the RTD can be locked to the phase and frequency of the intensity modulated optical signal delivered via the optical signal delivery system. This injection locking occurs as the modulation frequency approaches the free running oscillation frequency.