Antenna Coupling Cancellation in Portable Wireless Devices

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Solution Overview

Problem

Conventional diversity receiving devices are too large for portability and suffer from decreased sensitivity due to antenna coupling and correlation, which complicates high-sensitivity reception.

Innovation Solution

A method and wireless device design where the first and second antennas are placed with a distance between their feeding points within ½ of the wavelength of the received radio wave, utilizing a sensor, amplitude-phase regulators, tuners, and a controller to optimize reception quality by canceling coupled components and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional diversity receiving devices are reduced to portable size, then portability is improved, but receiving sensitivity decreases due to antenna coupling and correlation

Engineering Contradiction:

Improvedevice sizeVSAvoidreceiving sensitivity

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent converts the harmful antenna coupling effect into a beneficial one by intentionally generating a synthetic coupling signal that mimics the harmful coupling. This synthetic signal is then subtracted from the received signal to cancel out the actual harmful coupling, thereby improving receiving sensitivity in portable devices with closely spaced antennas

Inventive Principle:

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

Solution Approach 2:

The patent applies preliminary anti-action by generating and subtracting a synthetic coupling signal before the harmful coupling degrades the reception quality. The coupling cancellation unit proactively removes the coupling effect by introducing an equal but opposite signal, preventing the sensitivity loss that would otherwise occur in portable devices

Inventive Principle:

Principle #9Preliminary anti-action

2Length of stationary object

If antenna distance is reduced for portability, then device compactness is improved, but antenna coupling and correlation increase

Engineering Contradiction:

Improveantenna distanceVSAvoidantenna coupling and correlation

Core Design Contradiction:

Length of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful coupling effect into a beneficial one by intentionally generating a synthetic coupling signal that mimics the harmful coupling. This synthetic signal is then subtracted from the received signal to cancel out the actual harmful coupling, thereby improving receiving sensitivity in portable devices with closely spaced antennas

Inventive Principle:

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

Solution Approach 2:

The coupling cancellation unit acts as an intermediary that introduces a synthetic coupling signal as a mediator between the two antennas. This intermediary signal represents the harmful coupling effect and allows for its precise cancellation by subtraction, enabling close antenna spacing without performance degradation

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration maximizes receiving sensitivity by effectively canceling coupled components and noise, enabling high-sensitivity and stable reception in portable devices.

Implementation Method 1

a first sensor (28) which outputs a first pickup signal containing a coupled component induced from the second antenna (29)

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a first amplitude-phase regulator (12) which controls an amplitude and a phase of a first pickup signal outputted from the first sensor (28)

Methodology Applied

Scientific EffectAmplitude and phase modulation:

Implementation Method 3

a first adder (13) which receives and adds the output signal of the first antenna (19) and an output signal of the first amplitude-phase regulator (12) as two output signals and outputs an addition result

Methodology Applied

Scientific EffectVector synthesis:

Data Source

PatentUS8086202B2Method for removing the coupling and correlation of antennas, and wireless device having the function of removing the coupling and correlation of antennas

Publication Date: 2011.12.27 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

A wireless device, which employs the method and function of removing the coupling and correlation of antennas, picks up the noise components released from inside the device together with the current induced to a second antenna. The wireless device then controls the amplitude and phase of the pickup signal so as to optimize the reception quality signal for received signal, and additively combines it with the signal received from the first antenna. The coupled component, which is induced from the first antenna to the second antenna, is cancelled together with the noise component, thus mainly cancelling the largest cause of desensitization. This results in the maximization of the receiving sensitivity.