Gte Automatic Electric Laboratories Incorporated

California Microwave, Inc.

Robert G Rogers

A microwave oscillator having very low phase noise characteristics has a reflection oscillator circuit coupled to a right-circular cylindrical resonant cavity designed to operate in the TE.sub.011 mode. The resonator length L and inner diameter D are restricted to a range of values such that (D/L).sup.2 is less than 2.5 but greater than 1.7. To suppress the TM.sub.111 resonant modes in the resonator, two techniques are employed. A single tuning post is disposed on either resonator end plate at a point where the TM.sub.111 electric field Z-component is a maximum. The post length is adjustably fixed to maximize the output microwave power at the cavity output port. Each end plate also has a continuous gap separating each plate from the housing to suppress electric field currents of the TM.sub.111 mode flowing on the inner surface of the resonator.

Oscillator coupled through cylindrical cavity for generating low noise

A -DC to +DC voltage converter having one input and one output terminal connected to ground and regulator circuitry responsive to a control voltage for regulating the magnitude of output current delivered to a load impedance connected across the output terminals. Apparatus producing the control voltage comprises a passive resistive bridge circuit having one pair of nodes connected between the other input and other output terminals and a current sensing resistor in one arm of the bridge so as to pass load current to the other output terminal, a difference voltage that is the control voltage being developed between the second pair of nodes of the bridge. In one embodiment, the bridge comprises a potentiometer having a moveable contact connected to the other input terminal, and first and second pairs of series connected resistors connected between opposite sides of the potentiometer and opposite sides of the current sensing resistor. The potentiometer is adjusted to make the difference voltage between junctions of resistors of the pairs thereof a desired value for a prescribed maximum load current in the current sensing resistor. In an alternate embodiment that is also responsive to input current, the potentiometer is replaced by fixed resistor connected to the other input terminal and having opposite sides thereof connected to ends of associated series connected resistors, one of the other resistors being variable for adjusting the bridge.

Current sensing circuit for power supply with series control transistor

The embedding network of a microwave oscillator comprises three lengths of parallel conductors supported above a ground plane and having odd and even mode short circuits thereon. Two of the conductors are connected to different ones of the electrodes of a bipolar microwave transistor which has a third electrode connected to ground. A load is connected between the third conductor and ground. Physical and electrical characteristics of the network are varied to cause parameters thereof to be desired values which yield maximum output power and oscillation at desired frequencies.

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Los Altos, CA, United States of America

Robert G Rogers