Abstract: Coaxial, impedance-matched, four-port 180.degree. hybrid junctions for multioctave bandwidth operation include a gap in the outer shields of a port and a stub line at their interface for forming a uniform electric field within the gap. This gap and the interconnections between inner conductors and shields of certain ports and the stub, and the lengths of the port and stub lines are such that power input to a first port divides equally and in phase between two other ports with matched impedances and no power is at present at the fourth port. Similarly power fed into the fourth port divides equally, but 180.degree. out of phase, between the two other ports with matched impedances and no power is present at the first port.

Abstract: A resonant structure, for supporting electromagnetic (EM) oscillations win a frequency range of approximately 10 GHz to 1000 GHz, and whose resonant properties are controlled by light. The structure includes an interaction material for absorbing light and forming a plasma of electron-hole pairs within the material. Kinetic and potential energy, which are stored in the EM oscillations within the resonant structure, change as a result of the plasma and shift the frequency of the oscillations.

Abstract: An inverse reflex tetrode (IRT) for producing an intense pulsed beam of i includes a real cathode having a curved or conical surface which is substantially transparent to the ions; first anode and second anode, or grid, which are spaced apart and are at the same potential, the first anode being between the real cathode and the second anode and having a curved or conical surface approximately parallel to the surface of the real cathode, and also being formed from a dielectric material such as polyethylene; a curved or conical hollow anode stalk which supports both anodes; and a virtual cathode which is formed by electrons that are emitted by the real cathode and pass through the first anode. The real cathode and first and second anodes are enclosed in a vacuum chamber and are immersed in an applied external magnetic field. The IRT receives an electrical pulse from a high-voltage pulse generator.

Abstract: An interferometric waveguide amplitude modulator for conducting optical egy, and having an integral means for producing a linear response to a small applied voltage (approximately less than 100 volts), includes a first waveguide arm which has an increased physical length relative to a second waveguide arm, the increase .DELTA. being defined by .DELTA.=.pi./(2Kn), where K=2.pi./.lambda. and K is the free-space wavevector, .lambda. is the free-space wavelength of the optical energy and n is the index of refraction of the waveguide material. The increase, .DELTA., provides an integral bias of .pi./2 radians to the modulator for producing a linear response to a small applied voltage.

Abstract: A reciprocal phase shifter for optically controlling the phase of microwa millimeter, and submillimeter wavelength electromagnetic energy includes a source of light and a waveguide which comprises an interaction material for absorbing the light and forming a plasma of electron-hole pairs within the material. The plasma interacts with a traveling wave in the waveguide. The speed at which the wave propagates changes in the interaction region and thereby changes the phase of the wave.

Abstract: A fire detection system which includes an environmental sampling assembly upled to a programmable digital processor for detecting a threat of fire and reducing the occurrences of false alarms in a changing environment. The sampling assembly comprises a network of air ducts, a chamber, two sensors, and an exhaust fan. The processor includes two analog-to-digital (A/D) converters, a multiplexed digital summer, short and long-term storage mediums, a signal magnitude comparator, logic circuitry, and a timing generator. The fan continuously draws ambient air through the air ducts and the chamber. Sensors within the chamber sample the air. If the sensors detect particulates of combustion in the air, the sensors provide electrical signals of varying amplitudes, which amplitudes depend on the number and sizes of the particulates being sampled, to the A/D converters of the processor.

Abstract: An apparatus for amplifying coherent radiation at millimeter and submillimeter wavelengths includes the combination of a travelling-wave-tube cyclotron-maser-amplifier structure and a magnetron-injection electron gun. The amplifier structure includes a fast-wave drift tube and an electromagnetic wave launcher within the bore of a superconducting magnet. The magnetron-injection electron gun is also within the bore of the magnet and is coupled to the drift tube. As a travelling wave is launched in a preferred mode in the drift tube, the electron gun injects an annular beam of relativistic electrons having both large energy transverse to the axis of the device and small energy spread into the drift tube so that the electrons gyrate at their cyclotron frequency in orbits about the lines of the axial magnetic field produced by the magnet. The travelling wave is amplified by extracting energy from the relativistic electron beam.

Abstract: The invention is a configuration of digital open-loop cancelers, each of ch uses a batch window sampling technique, for decorrelating a main input signal from a plurality of auxiliary input signals by using one or more iterations of cancellation. The main signal includes a desirable signal and undesirable interference signals. The auxiliary signals include the undesirable interference signals which are correlated with the interference of the main signal. Samples of the main signal and a first auxiliary signal are fed to a first digital canceler. The canceler batches them, (forms the samples in a group) and measures the correlation between the main signal and auxiliary signal. This measurement, or weight, is applied to each of the samples of the auxiliary signal which were used to establish the weight. The weighted auxiliary samples are subtracted from the main input signal to produce an output residue signal that is uncorrelated with the auxiliary signal.

Abstract: A method for constructing systems of refractory layers for use in making gallium arsenide (GaAs) semiconductor devices, having gold as the conducting electrode, which devices are thermally stable when thermally stressed up to about 600.degree. C. for approximately 24 hours. The method forms refractory layers of either tantalum-platinum-tantalum, or tungsten-platinum-tungsten, or titanium tungsten-platinum to develop both the Schottky barrier to GaAs and the diffusion barrier between gold and GaAs. Each of the refractories are individually deposited, at specific temperatures in the range of 50.degree. C. to 175.degree. C., on a GaAs wafer within a vacuum. The metalized wafer cools to room temperature and is removed from the vacuum. Contacts are then typically defined on the wafer and the wafer is subsequently bonded.