Raytheon Company

James W McClymonds

Michael G Adlerstein

John P Bettencourt

Paul J Duval

Paul M Alcorn

Michael S Davis

Michael H Cobb

Philip C Balas, Ii

Thomas K Arthur

Forming an ohmic contact sealing layer disposed at an intersection between a sidewall of an ohmic contact and a surface of a semiconductor; forming an ohmic contact sealing layer on the intersection between a sidewall of the ohmic contact and the surface of the semiconductor; and subjecting the semiconductor with the ohmic contact to a chemical etchant.

Ohmic alloy contact region sealing layer

An amplifier is provided having an electrically conductive structure. The structure has a waveguide network disposed in an inner region thereof. The network has an input section and an output section. The conductive structure has an amplifier input port and amplifier output port formed in outer wall portions of such structure. The network also includes a plurality of amplifier module input ports disposed in an outer surface of the structure. The amplifier input ports are coupled to the amplifier port through the input section of the network. The network further includes a plurality of amplifier module output ports disposed in said outer surface of the structure. The amplifier module output ports are coupled to the amplifier output port through the output section of the network. Each one of the amplifier module output ports is associated with one of the plurality of amplifier module input ports. The amplifier includes a plurality of amplifier modules. Each one of the amplifier modules has an input and an output. The input each amplifier module is coupled to a corresponding one of the amplifier input ports and the output of such module is coupled to the amplifier output port of the one of the amplifier output ports associated with such one of the amplifier input ports.

Microwave power amplifier

A four diode reflection amplifier having a relatively wide bandwidth of at least 5 percent over the frequency range of 43.5 to 45.5 GHz includes three magic Ts arranged to provide a 4-way passive power combiner. The 4-way passive power combiner symmetrically couples each of the four diode amplifiers to an input/output port of the reflection amplifier. To provide the improved bandwidth performance, a perturbation impedance in the form of a single shunt capacitance is inserted at the input/output port of the reflection amplifier to provide a selected perturbation in the load impedance and hence the reflection characteristic seen by the reflection amplifier over a selected band of operation of the amplifier.

Microwave reflectiion amplifiers having increased bandwidth

A power combiner circuit for combining a plurality of signals to provide output power to a load over a broad range of operating frequencies includes a resonant cavity and a plurality of negative resistance diodes which couple such signals into the resonant cavity. Each one of the negative resistance diodes is disposed in a corresponding one of a like plurality of coaxial oscillators. In a first embodiment of the invention, the end of the cavity coupled to the load includes a plurality of members which provide a plurality of resonant structures and which are used to reduce variations in the impedance of the cavity over the operating range of frequency. In a second embodiment of the invention, each one of the coaxial oscillators includes a plurality of ring members used to match the impedance of the diode to that of the cavity and to reduce variations in the impedance of the cavity over the operating range of frequency. Since the impedance of the negative resistance diodes is a relatively slow changing function of frequency, reducing variations of the cavity impedance as a function of frequency provides a requisite impedance match between the diodes and the cavity over a broad range of operating frequency and, hence, provides high output power over such range of operating frequency.

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Waltham, MA, United States of America

James W McClymonds