Gyrator Circulator With Cancellation Paths for CMOS Full-Duplex RF

Solution Overview

Problem

The implementation of non-reciprocal circulators for full-duplex transceivers is hindered by the use of ferrite materials, which cannot be integrated into CMOS IC technology and require external magnets, making them bulky and expensive.

Innovation Solution

The development of circulators using a gyrator architecture with cancellation paths and switch groups that introduce phase shifts, enabling non-reciprocal phase and amplitude characteristics without the need for ferrite materials, allowing for compact and cost-effective integration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ferrite materials are used to implement non-reciprocal circulators, then non-reciprocal signal flow is achieved, but the device becomes bulky and expensive due to external magnet requirements

Engineering Contradiction:

Improvenon-reciprocal signal flowVSAvoiddevice bulkiness

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent replaces the mechanical ferrite-based non-reciprocal system with an electronic implementation using a gyrator circuit. The gyrator uses active electronic components (transistors, capacitors, inductors) to achieve non-reciprocal behavior through electrical means rather than magnetic materials, eliminating the need for bulky external magnets and ferrite components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental operating parameters from magnetic field-based non-reciprocity to electrical impedance-based non-reciprocity. By using a gyrator with specific impedance characteristics (Z12 = -Z21), the system achieves non-reciprocal signal flow through electrical parameter manipulation rather than magnetic material properties.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If ferrite materials are used to implement non-reciprocal circulators, then non-reciprocal signal flow is achieved, but manufacturing cost increases due to external magnet requirements

Engineering Contradiction:

Improvenon-reciprocal signal flowVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical ferrite-based non-reciprocal system with an electronic implementation using a gyrator circuit. The gyrator uses active electronic components (transistors, capacitors, inductors) to achieve non-reciprocal behavior through electrical means rather than magnetic materials, eliminating the need for bulky external magnets and ferrite components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses standard electronic components (resistors, capacitors, inductors, transistors) that are inexpensive and readily available in CMOS technology, replacing expensive ferrite materials and external magnets with cheap, integrable electronic components.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If ferrite materials are used to implement non-reciprocal circulators, then non-reciprocal behavior is achieved, but integration with CMOS IC technology is prevented

Engineering Contradiction:

Improvenon-reciprocal behaviorVSAvoidCMOS integration capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical ferrite-based non-reciprocal system with an electronic implementation using a gyrator circuit. The gyrator uses active electronic components (transistors, capacitors, inductors) to achieve non-reciprocal behavior through electrical means rather than magnetic materials, eliminating the need for bulky external magnets and ferrite components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention creates a universal non-reciprocal circuit block (gyrator) that can be implemented using standard CMOS electronic components, making it adaptable to integrated circuit technology. The gyrator serves as a multi-functional building block that can be integrated into various RF and microwave systems without requiring specialized ferrite materials or external magnets.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution achieves non-reciprocal phase and amplitude characteristics, enabling efficient full-duplex communication while avoiding the limitations of ferrite-based circulators, such as bulkiness and high cost, and allowing for integration with CMOS IC technology.

Implementation Method 1

a gyrator having a first side and having a second side connected to a third port

Methodology Applied

Scientific EffectGyrator effect:

Implementation Method 2

a first cancellation path that is connected between the first port and the third port and that introduces a current that is 90 degrees out of phase with a first voltage at the first port

Methodology Applied

Scientific EffectPhase cancellation: Interference

Data Source

PatentEP3791468B1Circuits and methods for circulators including a plurality of cancellation paths

Publication Date: 2024.05.29 THE TRUSTEES OF COLUMBIA UNIV IN THE CITY OF NEW YORK

Figure 1A~1D
Figure 2A~2D
Figure 3

AI summary

A circulator, comprising: a gyrator having a first side (1S) and a second side (2S) connected to a third port; a first transmission line section (TLS) having a 1 S connected to the 1 S of the gyrator and a 2S connected to a first port; a second TLS having a 1S connected to the first port and having a 2S connected to a second port; a third TLS having a 1S connected to the second port and having a 2S connected to the third port; a first cancellation path (CP) that is connected between the first port and the third port and introduces a current that is 90 degrees out of phase with a first voltage at the first port; and a second CP that is connected between the second port and the third port and introduces a current that is orthogonal to the current introduces by the first CP.