Symmetric Feed-Wire Antenna Module for Higher XPD

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Solution Overview

Problem

Existing antenna modules with planar radiation electrodes face challenges in improving cross-polarization discrimination (XPD) due to asymmetric current distribution caused by feed wire configurations, which can lead to increased cross-polarized wave interference.

Innovation Solution

The antenna module employs a feed wire configuration with two parallel paths of equal length, disposed in line symmetry with respect to the straight line connecting the feed points, to ensure symmetric current distribution and phase opposition between feed points, thereby enhancing XPD.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single feed wire is used to supply signals to two feed points, then the structure is simple, but asymmetric current distribution occurs reducing XPD

Engineering Contradiction:

Improvefeed wire structureVSAvoidcross-polarization discrimination

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The feed wire is segmented into two separate paths (first path and second path) that connect the first feed point to the second feed point. Each path is configured with equal length and disposed in line-symmetric arrangement, creating symmetric current distribution that improves XPD while maintaining structural simplicity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies symmetry rather than asymmetry - the two feed paths are configured to be line-symmetric with respect to the straight line connecting the two feed points. This symmetric arrangement ensures equal current distribution and phase opposition, resolving the XPD degradation caused by asymmetric single-wire configurations

Inventive Principle:

Principle #4Asymmetry

2Reliability

If feed wire position is optimized to improve XPD, then cross-polarized wave reduction is achieved, but the design becomes more complex

Engineering Contradiction:

Improvecross-polarization discriminationVSAvoidfeed wire configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent optimizes the local quality of the feed wire configuration by ensuring equal path lengths and line-symmetric arrangement between the two feed paths. This localized optimization at the feed wire level achieves improved XPD without requiring complex overall antenna structure modifications

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameters of the feed wire configuration - specifically setting both paths to equal length and arranging them in line-symmetric fashion. These parameter optimizations improve current distribution symmetry and XPD while maintaining design simplicity

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11837801B2Antenna module and communication device equipped with the same

Publication Date: 2023.12.05 MURATA MFG CO LTD

AI summary

An antenna module includes a radiation electrode in which a radio frequency signal is supplied to a first feed point and a second feed point. The antenna module further includes a feed wire configured to supply a radio frequency signal to the first feed point of the radiation electrode and a feed wire branching from the feed wire and configured to supply a radio frequency signal to the second feed point. The feed wire includes two paths connected in parallel between the first feed point and the second feed point and having the same length. The paths are disposed so as to be mutually line-symmetric in plan view of the antenna module with respect to a straight line connecting the first feed point to the second feed point.