Circulator-Based Transceiver Diplexer Elimination

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Solution Overview

Problem

Conventional microwave point-to-point transceivers face significant challenges in achieving adequate isolation between transmit and receive channels due to electromagnetic interference, leading to reduced receiver sensitivity and increased costs associated with large, complex diplexers that are difficult to configure and install.

Innovation Solution

The implementation of a circulator-based transceiver system that uses a correction signal and echo cancellation techniques to attenuate coupled transmit signals and noise in the receive path, improving signal sensitivity and reducing interference without the need for extensive physical isolation or complex filtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If diplexers are used to provide isolation between transmit and receive channels, then isolation requirements are met, but device complexity and size increase significantly

Engineering Contradiction:

Improveisolation between transmit and receive channelsVSAvoidcomplexity of diplexer assembly

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the harmful coupled transmit signal from the receive path by generating an inverse cancellation signal that is combined with the receive signal to eliminate the interference, thereby removing the need for complex diplexer filtering structures

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a circulator as an intermediary component that enables the transmit signal to serve dual purposes: both transmission and as a reference for generating the cancellation signal, simplifying the overall system architecture

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If diplexers are used to provide isolation between transmit and receive channels, then isolation requirements are met, but manufacturing cost increases

Engineering Contradiction:

Improveisolation between transmit and receive channelsVSAvoidmanufacturing cost of diplexer

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a copy of the transmit signal through the circulator to generate the cancellation signal, using the existing transmit signal as a template rather than requiring separate complex filtering components

Inventive Principle:

Principle #26Copying

3Reliability

If shielding assemblies and common-mode filters are used to prevent transmit coupling, then some isolation is achieved, but receiver sensitivity is still insufficient

Engineering Contradiction:

Improveisolation between transmit and receive channelsVSAvoidreceiver sensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful coupled transmit signal into a useful reference by using it to generate the cancellation signal through the circulator, transforming the interference problem into a solution mechanism

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements a feedback mechanism where the circulator feeds the transmit signal back to the receive path to generate the cancellation signal, creating a closed-loop system that actively compensates for interference

Inventive Principle:

Principle #23Feedback

4Productivity

If transmit and receive channels are placed adjacent to each other to meet spectrum management constraints, then frequency utilization is improved, but electromagnetic interference increases

Engineering Contradiction:

Improvespectrum utilization efficiencyVSAvoidelectromagnetic interference from transmit to receive channel

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach enhances receiver sensitivity and reduces interference by effectively canceling out coupled transmit signals and noise, thereby improving the performance of microwave point-to-point systems while minimizing costs and complexity.

Implementation Method 1

The circulator may be coupled to a transmit signal path and a receive signal path

Methodology Applied

Scientific EffectCirculator:

Implementation Method 2

uses a correction signal and echo cancellation techniques to attenuate coupled transmit signals and noise in the receive path

Methodology Applied

Scientific EffectEcho cancellation: Echo

Data Source

PatentUS9287920B2Diplexer elimination in microwave point-to-point FDD systems

Publication Date: 2016.03.15 MAXLINEAR ASIA SINGAPORE PTE LTD

AI summary

A circulator based transceiver sharing a common antenna between a receive signal path and a transmit signal path is disclosed. Techniques to reduce coupled transmit signals and coupled transmit noise in a receive signal path, implemented in a variety of embodiments is disclosed allowing elimination of a diplexer, simplification of circulator design and reduction of transceiver cost. The transceiver includes means to generate and couple a correction signal into the receive signal path to attenuate coupled transmit signal in the receive path. Furthermore, the transceiver includes echo cancellation techniques to attenuate transmit noise in the receive signal path. Methods to utilize the transceiver to attenuate coupled transmit signal and transmit noise may improve transceiver efficiency, for example, in demodulation techniques and processing of data signal.