PCB Antenna Discontinuities for Harmonic Suppression

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Solution Overview

Problem

Mobile communication devices face challenges in designing antennas that effectively manage multiple communication services without radiating unwanted frequencies, leading to electromagnetic compatibility issues and interference due to harmonic and intermodulation frequencies.

Innovation Solution

Introducing intentional discontinuities in the antenna patterns to specifically target and reduce spurious radiation at undesired frequencies, using a method that involves measuring radiation patterns and modifying the antenna layout with various types of discontinuities such as corners, wiggles, blobs, and bow ties to prevent activation at problematic frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple antennas are included to support various communication services, then service coverage and functionality are improved, but device complexity and space requirements increase

Engineering Contradiction:

Improveservice coverageVSAvoidantenna arrangement complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by designing a single antenna structure that can support multiple communication services including NFC, RFID, Bluetooth, Wi-Fi, and cellular bands. The antenna is configured with multiple radiating elements and adjustable parameters to perform various communication functions, eliminating the need for separate dedicated antennas for each service and thereby reducing device complexity while maintaining service coverage

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If antenna design is optimized for specific frequency bands, then radiation efficiency at intended frequencies is improved, but susceptibility to harmonic activation at unintended frequencies increases

Engineering Contradiction:

Improveradiation efficiencyVSAvoidharmonic radiation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by introducing discontinuities at specific locations along the antenna radiating elements. These localized modifications create frequency-selective properties that allow the antenna to maintain efficient radiation at intended frequencies while suppressing harmonic activation at unintended frequencies. The discontinuities are strategically placed to target specific harmonic frequencies without compromising overall antenna performance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by modifying the physical characteristics of the antenna structure through added discontinuities. These discontinuities alter the electrical length, impedance, and current distribution along the radiating elements, creating frequency-selective behavior that suppresses harmonic radiation while preserving desired frequency performance

Inventive Principle:

Principle #35Parameter changes

3Productivity

If driver circuits generate non-sinusoidal waveforms for communication services, then data transmission capability is improved, but unwanted harmonic emissions increase

Engineering Contradiction:

Improvedata transmission capabilityVSAvoidspurious emissions

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of harmonic emissions into a beneficial filtering mechanism. The discontinuities in the antenna structure are designed to specifically attenuate harmonic frequencies generated by non-sinusoidal driver circuits, transforming what would be harmful spurious emissions into controlled frequency-selective behavior. This allows the antenna to handle complex modulation schemes while automatically suppressing unwanted harmonics

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 effectively reduces unwanted spurious emissions without affecting desired radiation characteristics, improving electromagnetic compatibility and reducing interference, and can be implemented without significant additional material or cost.

Implementation Method 1

antennas for various communication services... antennas radiate at frequencies outside of the intended band of operation... radiation characteristics at desired frequencies

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

harmonic frequency of an intended radiation frequency of a neighboring antenna... induced currents to radiate at frequencies not intended

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9065167B2Antenna modification to reduce harmonic activation

Publication Date: 2015.06.23 NXP USA INC

AI summary

An arrangement for modifying a printed circuit antenna of the type used in mobile communication devices includes introducing one or more discontinuities into a printed circuit pattern of the antenna so that it is not activated at undesired frequencies. Examples of discontinuities include localized narrowing the printed circuit strip, localized widening of the printed circuit strip and localized changing of the shape of the printed circuit strip.