Coil and Planar Antenna for Compact Wireless Devices

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Solution Overview

Problem

Existing antenna devices for high-frequency communication systems face a trade-off between miniaturization and communication distance, as larger coil antennas are required for effective communication, hindering the development of compact communication terminal apparatuses.

Innovation Solution

The integration of a coil antenna with a booster antenna, where the coil conductor is wound around a magnetic core and coupled to a planar conductor through an electromagnetic field, allowing for a smaller footprint while maintaining a predetermined communication distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coil antenna is made large to ensure communication distance, then the communication distance is improved, but the device size increases and miniaturization is hindered

Engineering Contradiction:
Improvecommunication distanceVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The invention introduces a planar conductor extending in the X-direction perpendicular to the coil antenna's winding axis (Y-direction), creating a boomerang-shaped configuration. This dimensional extension allows the antenna to achieve extended effective area and improved communication distance without increasing the footprint area in the XY-plane, thus resolving the contradiction between communication distance and device size.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention combines two different antenna structures - a coil antenna with magnetic core and a planar conductor - into a single composite antenna device. The coil antenna provides magnetic coupling capability while the planar conductor extends the effective area, creating a composite structure that achieves both compact size and sufficient communication distance through synergistic interaction of different components.

Inventive Principle:
Principle #40Composite materials

2Volume of moving object

If the coil antenna is made small for miniaturization, then the device size is reduced, but the effective area decreases and communication distance becomes insufficient

Engineering Contradiction:
Improvedevice sizeVSAvoidcommunication distance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

By extending the planar conductor in the X-direction perpendicular to the coil antenna's plane, the invention effectively increases the antenna's active area without increasing its footprint. This dimensional extension allows small coil antennas to achieve sufficient communication distance through the extended planar conductor that captures additional magnetic flux.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a large coil antenna is used to ensure effective communication, then the communication performance is improved, but the footprint area increases

Engineering Contradiction:
Improvecommunication performanceVSAvoidfootprint area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The planar conductor extends in the X-direction (perpendicular to the coil's winding axis), creating a boomerang configuration that increases the effective area without increasing the XY-footprint. This allows the antenna to maintain excellent communication performance while achieving compact footprint suitable for modern portable devices.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Volume of moving object

If the antenna size is reduced for compact terminal apparatus, then the device compactness is improved, but the gain in specific direction decreases

Engineering Contradiction:
Improvedevice compactnessVSAvoidantenna gain
Core Design Contradiction:
Volume of moving objectVSPower

Solution Approach 1:

The planar conductor extending in the X-direction creates a boomerang configuration that concentrates and directs electromagnetic energy in specific directions, enhancing the antenna gain in those directions while maintaining compact overall size. The extended planar structure acts as a directional radiator, improving gain without requiring larger antenna dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 enables a small-sized communication terminal apparatus with a high gain in a specific direction, ensuring effective communication over a desired distance without the need for large antenna sizes.

Implementation Method 1

The booster antenna includes a planar conductor functioning as a booster coupled to the coil antenna through an electromagnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the communication distance between the antenna devices depends on magnetic flux passing through the coil antennas

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Data Source

PatentUS9997834B1Antenna device and communication terminal apparatus
Publication Date: 2018.06.12 MURATA MFG CO LTD

AI summary

An antenna device includes a base including a planar conductor disposed thereon, and a coil antenna. The coil antenna includes a coil conductor wound around a magnetic core. The coil antenna is arranged such that a coil opening of the coil conductor is closed to an edge of the planar conductor. A current passing through the coil conductor induces a current in the planar conductor. Thus, a first magnetic flux occurs in the coil antenna, and a second magnetic flux occurs in the planar conductor. Therefore, a third magnetic flux occurs in an area of the planar conductor. Accordingly, the antenna device achieves a small footprint, a small-sized communication terminal apparatus and a desired communication distance.