Abstract: An underlay cellular telephone system disposed within a main cellular telephone system is provided. Specifically, the invention includes a system and method suitable to provide an independent cellular system which operates as an underlay system to an existing main cellular system and provides public or private cellular service without the need for system returning or frequency coordination with the main cellular system. The main cellular system includes a plurality of contiguous cells, each of said cells having a fixed set of frequencies (or "channels") and a main controller (also referred to as a "switch" or "MSC") operatively coupled to said cells for coordination and control of communication within the main cellular system. The underlay cellular system operates to determine which of the fixed set of frequencies are under-utilized and establishes communication over any number of the under-utilized frequencies without coordination and control by the main controller.

Abstract: A wireless base station receiver receives weak signals from mobile units at a first position using a first receiver configuration and strong signals from mobile units at a second position using a second receiver configuration. The base station receiver includes an input terminal to receive an inbound signal from each mobile unit. A diplexer is coupled to the input terminal and configured to receive the inbound signal and to pass a first frequency band of the inbound signal as a first signal, and to pass a second frequency band of the inbound signal as a second signal. An attenuator is coupled to the diplexer and configured to attenuate the second signal to create a third signal. A downconverter is coupled to the diplexer and the attenuator and configured to downconvert the first signal and the third signal to provide a downconverted inbound signal. An analog to digital converter coupled to the downconverter and configured to convert the down converted inbound signal to a digital signal.

Abstract: A high dynamic range mixer apparatus and mixing method where a wide high dynamic range is achieved in part due to the use of a series pair of switching devices that are matched so as to afford complete or substantial cancellation of nonlinearity distortion. The inventive structure and method preserves the compensation and cancellation mechanism of the series pair of back-to-back connected FETs without the need for either of an intermediate frequency (IF) balun or a radio-frequency (RF) balun. Typically, the switching devices are PETs, such as for example MESFETs, connected source-to-source with one drain terminal grounded, and a non-grounded or floating switching signal applied between the common gate and common source terminals.

Abstract: A plurality of base stations communicate with a plurality of mobile units. Each base station includes a base station transceiver that receives inbound information from the mobile units and transmits outbound information to the mobile units. A mobile switching center (MSC) is coupled to the base stations and communicates the inbound information and outbound information with the base stations. The base stations each include signal detectors that detect signal strength of the inbound information, co-channel information and adjacent channel information. The MSC maintains a table of signal strength per communication channel and allocates communication channels to the base stations based on the signal strength information. The inventive dynamic channel allocation includes several channel allocation algorithms that can be active at the same time. Only one of the algorithms is active at a time. The choice of the algorithm is based on current interference conditions and traffic load.

Abstract: A plasma enhanced chemical processing reactor and method. The reactor includes a plasma chamber including a first gas injection manifold and a source of electromagnetic energy. The plasma chamber is in communication with a process chamber which includes a wafer support and a second gas manifold. The reactor also includes a vacuum system for exhausting the reactor. The method includes the steps of generating a plasma within the plasma chamber, introducing at least one gaseous chemical into the process chamber proximate to the wafer support, applying r.f. gradient to induce diffusion of the plasma to the area proximate the wafer support, and exhausting the reactor in a substantially symmetrical manner.

Abstract: An electrostatic support assembly for supporting a substrate. The support assembly includes a non-metallic body having a support surface for supporting the substrate and an integral peripheral outer portion extending outwardly from and substantially surrounding the support surface of the substrate. The support assembly also includes at least one electrode carried by the non-metallic body for electrostatically coupling a substrate to the support surface of the non-metallic body and a base coupled to the underside of the non-metallic body for the transfer of heat between the non-metallic body and the base.

Abstract: An emitter locator for locating an emitter transmitting an emitter signal includes a plurality of scatters and a base station. The plurality of scatterers are located at predetermined positions, where each scatterer includes a modulator configured to modulate an electrical signal on an antenna and configured to receive emitter signal and to modulate the emitter signal to generate a scattered signal. The base station is configured to receive a composite signal containing the emitter signal and a plurality of the scattered signals, where the base station includes a processor configured to separate the scattered signals from the composite signal and to identify relative power levels of the scattered signals to determine a location of the emitter. Advantages of the invention include the ability to locate emitters in an efficient and cost effective manner by using scatterers and a base station.

Abstract: A wayside station communicates with a plurality of mobile stations over a wireless communication network. In one embodiment, a wayside station includes a transceiver configured to receive an inbound signal from a mobile station and to transmit an outbound signal to the mobile station. The transceiver has a first switch that is configured to selectively deliver the inbound signal to one of a first band pass filter (BPF) and a second BPF. A second switch is coupled to the first BPF and to the second BPF, and configured to selectively receive the inbound signal from one of the first BPF and the second BPF. A detector is coupled to the second switch and configured to detect the inbound signal, to convert the inbound signal to inbound data and to transfer the inbound data to a processor. The processor decodes the inbound data and processes the data.

Abstract: A shield assembly for protecting an exposed surface of an injector. The shield assembly includes a shield body having a front and back walls and at least one plenum therebetween, and at least one conduit coupled for delivering a gaseous substance to the plenum. The front wall includes a plurality of apertures for removing the gaseous substance from the plenum. The apertures are configured to provide a substantially uniform distribution of the gaseous substance across an exterior region of the front wall. At least one support member extends between the front and back walls, and is positioned to transfer forces from the front wall to the back wall to thereby reinforce the front wall against collapse.

Abstract: A base station (BS) communicates with a plurality of mobile users in a platform. In one embodiment, the base station and mobile services center (MSC) associates all the mobile users with the platform. The BS and MSC then associate a movement of the platform from one cell to another with a handoff of all the mobile users in the platform. The handoff is complete while the overhead is minimized. Exemplary embodiments are provided for use with the Advanced Mobile Phone Service (AMPS) protocol.

Abstract: A chemical vapor deposition apparatus and method for forming an oxide thin film on a surface of a substrate. The system includes a reaction chamber having a support for holding a substrate and an injector positioned to inject gaseous substances into the reaction chamber. The injector includes a central injection port coupled to a source of ozone and at least two outer injection ports positioned on opposite sides of the central injection port and coupled to a source of chemical reagent. Ozone and chemical reagent are separately injected into the reaction chamber through the central injection port and outer injection ports, respectively, with the ozone and chemical mixing in the area between the injector and the substrate.

Abstract: A compensated mixer including a radio frequency (RF) balun through which RF signals are transferred, and a local oscillator (LO) balun for receiving an LO signal. In an exemplary implementation the mixer further includes a diode ring quad circuit for mixing RF signals received by the RF balun with the LO signal received by the LO balun. During operation the diode ring quad circuit develops, between first and second nodes therein, a capacitive reactance arising from switching at the LO frequency. The mixer further includes a compensation inductor, connected between the first and second nodes, for cancelling the effect of the capacitive reactance at the LO signal frequency.

Abstract: A system for injecting a gaseous substance into a semiconductor processing chamber. The injection system includes at least one plenum formed in a plenum body and a plurality of nozzles associated with each plenum for injecting gaseous substances from the plenums into the chamber. A conduit structure transports gaseous substances along an indirect path from the plenum to the nozzles. The nozzles are positioned and configured to provide a uniform distribution of gaseous substances across the wafer surface.

Abstract: A protective shield and an atmospheric pressure chemical vapor deposition system including a protective shield. The shield includes a frame assembly including a pair of spaced end walls and a pair of side walls extending between and mounted to the end walls, and a plurality of shield bodies carried by the frame assembly. Each of the shield bodies includes a base, a perforated sheet carried by the base, a plenum between the base and the perforated sheet, and a gas delivery device for delivering an inert gas to the plenum at a flow rate such that the gas diffuses through the perforated sheet. The chemical vapor deposition system includes a plurality of processing chambers, a conveyor for transporting substrates through the processing chambers, buffer chambers isolating the processing chambers from the rest of the process path all enclosed within a muffle.

Abstract: An electrostatic support system for retaining a wafer. The support system generally includes a support body having a support surface for retaining said wafer, a voltage source coupled to the support body for electrostatically coupling the wafer to the support surface, and a cooling system for cooling the wafer. A plurality of arm members extend from the support body to a carriage assembly for releasably mounting the support body to the processing chamber with the support body and the arm members separated from the chamber floor. This invention also includes the method of supporting a wafer in a processing chamber which includes the steps of positioning the wafer on a wafer supporting surface, applying a voltage to an electrode assembly to electrostatically attract the wafer to the support surface and, after processing the wafer, substantially grounding the electrode assembly to sufficiently deactivate the electrostatic charge for release of the wafer from the support surface.

Abstract: A connector assembly for detachably connecting a coaxial transmission line connector to a strip lead formed on a printed wiring board is disclosed. The connector assembly includes a metallic housing to house a printed wiring board circuit having a micro-strip defined by a lead on one surface of the board and a ground plane on the other surface of the board. The housing includes a low-impedance, coaxial line section formed by an opening extending through one wall of the housing and a center conductor supported in the opening by a dielectric sleeve. A connector with a lead connected to the micro-strip lead and a body with a central insulated socket spaced from a ground plane on the surface of the board forms a transmission line section. The center conductor is slidably received in the socket, whereby the coaxial connector can be easily attached to connect the printed wiring board to the coaxial transmission line.

Abstract: A distributed microcellular communication system comprised of a plurality of subcells arranged within one or more conventional cells. The distributed microcellular communications system includes one or more remote site stations, each of which transmits and receives information signals over an assigned set of communications channels within an associated subcell. Each remote site station includes a wideband RF receiver network within which information signals received from mobile units are converted into reverse link digital information signals. Also disposed within each remote site station is a remote communications link transceiver for transmitting the reverse link digital information signals over a communications link to the central base station, as well as for receiving forward link digital information signals from the central base station.

Abstract: FET mixers requiring relatively low local oscillator power levels and having excellent isolation of the local oscillator signal relative to the radio and intermediate frequency signal. The mixer comprises a first and second FET transistor (Q1, Q2) having their gates and sources connected together such that the first and second FET transistors are in series; a local oscillator input circuit; a coupling network comprising a transmission line balun; a diplexer circuit; and a bias circuit. In one aspect, the transmission line balun divides the voltage of an incident traveling wave equally between the first and second transmission line components, and sums the currents of traveling waves generated by the transmission line components to generate an exitant traveling wave signal. The RF signal is completely reflected by each the FET transistors with no phase shift when they are nonconducting (OFF), and completely reflected by each of the FET transistors with a 180.degree.

Abstract: A plasma enhanced chemical processing reactor and method. The reactor includes a plasma chamber including a first gas injection manifold and a source of electromagnetic energy. The plasma chamber is in communication with a process chamber which includes a wafer support and a second gas manifold. The plasma generated in the plasma chamber extends into the process chamber and interacts with the reactive gases to deposit a layer of material on the wafer. The reactor also includes a vacuum system for exhausting the reactor. The method includes the steps of generating a plasma within the plasma chamber, introducing at least one gaseous chemical into the process chamber proximate to the wafer support and applying r.f. gradient to induce diffusion of the plasma to the area proximate the wafer support.

Abstract: A solution of hydrogen peroxide ?H.sub.2 O.sub.2 !, citric acid ?HOC(CH.sub.2 COOH).sub.2 COOH.H.sub.2 O!, and a salt of citric acid such as potassium citrate ?HOC(CH.sub.2 COOK).sub.2 COOK.H.sub.2 O!, and hydrogen peroxide ?H.sub.2 O.sub.2 !, in a proper pH range, selectively etches GaAs-containing Group III-V compounds in the presence of other Group III-V compounds. As an illustration, Al.sub.y Ga.sub.1-y As is selectively etched in the presence of Al.sub.x Ga.sub.1-x As (0.ltoreq.y<0.2 & x>0.2) when the pH range of the etchant solution is between approximately 3 and 6. The etchant solution described herein may be utilized in the fabrication of, for example, high-frequency transistors exhibiting improved saturated current (I.sub.dss) and threshold voltage (V.sub.th) uniformity.