Abstract: An array antenna is steered by moving two sets of optical fibers of different optical lengths between a number of light signal sources and an array antenna. By changing the lengths of the optical paths of the different light signal sources, the wave front can be steered. The light signal traverses five sections of optical delay lines with at least two selectable optical lengths. One set of selectable optical lengths provides coarse adjustment of steering, and a second set of selectable optical lengths provides fine adjustment of steering. The coarse adjustment is implemented by using a larger increment of selectable optical lengths between adjacent optical lengths than the increment for the fine adjustment. The antenna can serve both for a transmitter or a receiver.

Abstract: An array antenna is steered by changing the time delays of a local oscillator signal feeding a number of mixers, each fed by an individual antenna element. The beat frequency thus produced can be made in-phase by compensating time delays of different antenna elements in the array with different delays from the local oscillator. The delays from the local oscillator are obtained with optical fibers of variable lengths.

Abstract: An array antenna is steered by moving a set of optical fibers of different optical length between a number of light signal sources and an array of antennas. By changing the lengths of the optical paths of the different light signals sources, the wave front can be steered. The light signal traverses three sections of optical delay lines with at least one selectable optical length. In the first section, light signal from a point source travels through a first optical delay line and a lens to diverge and collimate the light beam with increased cross section. The collimated light beam is focused by second lens and incident one second optical line of selectable optical length. The light beam exiting from the other end of the second optical line is collimated again by a third lens to face a third optical line. The collimated light exiting from the second optical line is focused again by a fourth lens to feed the third optical line, which is connected at the other end to one element of the antenna array.

Abstract: An array antenna is steered by moving a set of optical filters of different optical lengths between a number of light signal sources and an array antenna elements. By changing the lengths, hence the time delays, of a plurality of the signal paths between the light signal source and the antenna array elements, the wave front can be steered. Each delay path comprises a selected fiber optic line and a fixed electrical delay line. In one embodiment the fiber optical lines assume a parabolic distribution in time delay. In another embodiment, the fiber optical lines assume a cosinusoidal distribution in time delay. Signals are fed to the fiber optic path through a laser diode and exit from the path through a photo-diode. The fiber optic lines are mounted on a rotatable disk, with two ends diametrically located at two different radii.

Abstract: The output matching networks normally included in a microwave power transistor package as well as the transistor combining network therefor are eliminated for heating applications, e.g. microwave ovens. In a preferred embodiment, the transistor dies of four microwave silicon bipolar power transistors are directly connected to the low impedance points of a common patch type antenna element, also referred to as an applicator, located within the wall of a heating chamber in place of a magnetron. Each pair of power transistors are electrically spaced one half wavelength apart and are located transverse to each other on the antenna. The transistors are operated in pairs with a 180.degree. phase difference so that mutually orthogonal longitudinal modes are excited in the antenna. Moreover, the transistors are frequency modulated over their prescribed frequency band to eliminate standing waves in the load, i.e. the article or substance being heated or cooked.

Abstract: A device for delaying signals fed to radiating elements of an array antenna by providing delay paths of selective lengths between respective antenna elements and a signal input source. A plurality of first optical fibers are provided, each having a selected length. A plurality of second optical fibers are also provided, each having a selected length. The first output fibers are alignable to the second fibers to form respective delay paths. At least one of the set of first fibers and set of second fibers is movable relative to the other so that when moved, selected first fibers are aligned with selected second fibers creating a particular delay path of a selected length from the input source to each radiating element.

Abstract: A device for delaying signals received from elements of an array antenna by providing delay paths of selectable lengths between respective antenna elements and signal processing means. A plurality of first optical fibers are provided, each having a selected length. A plurality of second optical fibers having selected lengths are also provided. The first fibers are alignable with the second fibers to form respective delay paths. At least one of the set of first fibers and set of second fibers is moveable relative to the other so that when moved, selected first fibers are aligned with selected second fibers creating a delay path of a selected length from each antenna element to the signal processing means.

Abstract: The present invention is directed to a four-region solid-state switching device whose topology readily links itself to light activation. Anode and cathode emitter regions of the device are disposed in the same surface of the device. Both base regions are exposed on a mesa portion disposed between the anode and cathode regions. The topology of the device is such that current flows across the device rather than through the device and light is introduced through the base regions perpendicular to the direction of current flow.

Abstract: An electronic device is provided comprising two or more discrete semiconductor devices in an electrical circuit relationship, hermetically sealed within a single case member. Electrical and thermal conductivity between the semiconductor devices and electrodes on the case member is established and maintained by the application of a compressive force to the case member. The compressive force applied to the case member is distributed to the individual semiconductor devices sealed within the case member.

Abstract: An integrated amplifying gate thyristor is provided with an integral diode in the thyristor structure in the same semiconductor body. The diode provides gate assist turn-off capability with the same gate electrode used to turn-on a pilot thyristor of the device. The common cathode-base region of the pilot and main thyristors also is common with the anode region of the diode. The current gain of the NPN transistor structure formed at the diode and the common anode-base region at the diode is less than the ratio of I.sub.FB /I.sub.g, where I.sub.FB is the forward anode current on triggering the main thyristor into the low impedance conduction state by applying a threshold negative gate assist current (I.sub.G) and an operating anode-cathode load potential, and I.sub.g is a negative gate current selected to assist in turn-off of the main thyristor.

Abstract: A transistor in which this effective emitter resistance which is determined by the geometry of the emitter metallization as disclosed. In the preferred embodiment, the emitter metallization comprises a series of circular "dots" which are distributed over the entire emitter area. The area of the "dots" with respect to the entire emitter area is selected such that the desired effective emitter resistance is achieved.

Abstract: An optical power transistor comprises a gallium arsenide laser diode disposed on the surface of a semiconductor diode. The ends of the laser diode are angled so that the laser radiation generated in the Fabry-Perot cavity is directed onto the surface of the semiconductor diode for creating electron hole pairs therein and thereby creating electrical current therethrough. In another embodiment, prism means are disposed on the ends of the laser diode for directing the laser radiation onto the semiconductor diode.

Abstract: An integrated amplifying gate thyristor is provided with an integral diode in the thyristor structure in the same semiconductor body. The diode provides gate assist turn-off capability with the same gate electrode used to turn-on a pilot thyristor of the device. The common cathode-base region of the pilot and main thyristors also is common with the anode region of the diode. The current gain of the NPN transistor structure formed at the diode and the common anode-base region at the diode is less than the ratio of I.sub.FB /I.sub.g, where I.sub.FB is the forward anode current on triggering the main thyristor into the low impedance conduction state by applying a threshold negative gate assist current (I.sub.G) and an operating anode-cathode load potential, and I.sub.g is a negative gate current selected to assist in turn-off of the main thyristor.