Broadband high frequency active MMIC circulator
AssigneeMotorola, Inc.
InventorsRichard M. Dougherty, Stephen W. Boser
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Abstract
A broadband high frequency active MMIC circulator which includes low parasitic devices (MESFETs or HEMTs) and shunt feedback for impedance contouring in conjunction with a cascode/cascade isolation/gain network. To achieve circulation, a common series feedback node is required for each active element. While conventional active circulator topologies require the use of a resistive element for operation with a deleterious effect on noise performance, this broadband high frequency active MMIC circulator functions with either resistive or reactive common series feedback. When reactive feedback is selected, major improvements in noise performance can be realized.
Claims12
An active monolithic microwave integrated circuit (MMIC) signal circulator capable of high frequency performance with contourable bandpass characteristics, the active MMIC signal circulator having a plurality of at least three input/output ports and comprising:
- a first cascode network, wherein the first cascode network comprises a plurality of at least two transistors, the first cascode network including a first node coupled to the first input/output port, a second node coupled to the third input/output port, and a common node;
- a second cascode network, wherein the second cascode network comprises a plurality of at least two transistors, the second cascode network including a first node coupled to the third input/output port, a second node coupled to the second input/output port, and a common node;
- a third cascode network, wherein the third cascode network comprises a plurality of at least two transistors, the third cascode network including a first node coupled to the second input/output port, a second node coupled to the first input/output port, and a common node;
- and
- common feedback means coupled to each of the common nodes of the first cascode network, the second cascode network, and the third cascode network.
A broadband high frequency active monolithic microwave integrated circuit (MMIC) circulator with contourable bandpass characteristics, the broadband high frequency active MMIC circulator comprising:
- common series feedback means connected to an electrical ground;
- a plurality of at least three input/output ports;
- a plurality of at least three isolation/gain means of the same number as and corresponding one for one to the plurality of input/output ports, wherein each isolation/gain means comprises a cascode network and is coupled to the common series feedback means and the plurality of isolation/gain means are electrically connected in a ring configuration alternating with the plurality of input/output ports so that each isolation/gain means is coupled to a unique pair of input/output ports.
Dependencies are inferred from the claim text.