Foldable Metallic Patch Counterpoise for Compact RF Devices

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Solution Overview

Problem

Small handheld communication devices often have insufficient surface area on their circuit boards to provide effective counterpoises for antennas, leading to attenuated or distorted radiation patterns, and existing conductive coatings are costly.

Innovation Solution

A foldable metallic patch is used as a counterpoise, sandwiched around the circuit board within the device's housing, providing a larger effective surface area without the high cost of conductive coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a small main circuit board is used in compact handheld devices, then device size is reduced, but the surface area available for counterpoise is insufficient leading to poor antenna performance

Engineering Contradiction:

Improvedevice sizeVSAvoidcounterpoise surface area

Core Design Contradiction:

Volume of moving objectVSArea of stationary object

Solution Approach 1:

The counterpoise transitions from a two-dimensional planar structure on the circuit board to a three-dimensional folded structure that wraps around the circuit board, utilizing vertical space and creating multiple surfaces (front, back, and side surfaces) to dramatically increase the effective counterpoise area within the same device volume

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The counterpoise is folded and nested around the circuit board in a compact configuration, with the circuit board positioned within the folded structure. This nesting arrangement maximizes the counterpoise surface area while maintaining a compact overall device form factor

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If conductive paint coating is sprayed on the inside surface of the housing to provide counterpoise, then antenna radiation pattern is improved, but manufacturing cost increases

Engineering Contradiction:

Improveantenna radiation patternVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention replaces expensive conductive paint coatings with a cost-effective metallic foil or mesh material that can be applied as a discrete component. This substitution significantly reduces material costs while maintaining the electrical conductivity and radiation pattern performance required for effective antenna operation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention replaces the chemical deposition process (spraying conductive paint) with a mechanical assembly process (attaching folded metallic patch to circuit board). This substitution simplifies manufacturing by eliminating complex coating equipment and processes while achieving the same electrical function through a straightforward mechanical attachment

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8130153B2Electronic device and electronic assembly

Publication Date: 2012.03.06 MOTOROLA SOLUTIONS INC

AI summary

An electronic assembly and electronic device used for radio frequency communications are presented. The electronic device has a housing and an antenna feed point at least partially enclosed in the housing. There is at least one circuit board enclosed in the housing. An antenna counterpoise is coupled to the feed point. The counterpoise is enclosed in the housing and the counterpoise includes a foldable metallic patch that is folded around the circuit board such that the circuit board is sandwiched between opposite facing portions of the foldable metallic patch.