Angled Feed Stalk Radiating Elements for Compact Multiband Antennas

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Solution Overview

Problem

Existing base station antennas face challenges in achieving a 65° azimuth Half Power Beamwidth (HPBW) with limited space, particularly when deploying multiband antennas that support both low-band and high-band frequency services, due to spatial constraints and the need for angled feed stalks that do not interfere with massive MIMO arrays.

Innovation Solution

The implementation of angled feed stalks with longitudinally spaced opposing end portions and angled segments between 30-60 degrees relative to the reflector, allowing for a more compact design that maintains effective RF transmission and reduces interference between low-band and high-band radiating elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If linear arrays of radiating elements are used to achieve 65° azimuth HPBW, then coverage throughout a 120° sector is improved, but the antenna width increases beyond commercially acceptable limits

Engineering Contradiction:

Improveazimuth coverage areaVSAvoidantenna width

Core Design Contradiction:

Area of stationary objectVSArea of moving object

Solution Approach 1:

The feed stalk is configured with an asymmetric angled orientation (e.g., 45 degrees from vertical) rather than a symmetric vertical alignment. This asymmetric positioning allows the radiating element to be laterally offset from the feed stalk axis, enabling compact lateral arrangement of multiple linear arrays while maintaining the required 65° azimuth HPBW for full 120° sector coverage

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

Instead of arranging linear arrays side-by-side in the lateral dimension only, the invention utilizes the vertical dimension by angling the feed stalks at oblique angles (30-60 degrees from vertical). This allows multiple linear arrays to be stacked vertically with compact lateral spacing, achieving the required azimuth coverage while reducing the overall antenna width to commercially acceptable limits

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiband antennas with multiple linear arrays are deployed to support both low-band and high-band services, then service versatility is improved, but spatial constraints and interference between arrays worsen

Engineering Contradiction:

Improvefrequency band supportVSAvoidinterference between radiating elements

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Adjacent linear arrays are positioned asymmetrically at different lateral offsets from their respective feed stalk axes. This asymmetric lateral separation creates sufficient spatial isolation between low-band and high-band radiating elements, reducing mutual interference while maintaining compact overall antenna dimensions for multiband operation

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The invention exploits the vertical dimension by configuring feed stalks at oblique angles (30-60 degrees from vertical) rather than vertical alignment. This vertical angular separation, combined with lateral offsets, creates three-dimensional spatial isolation between multiple linear arrays supporting different frequency bands, reducing interference while maintaining compact antenna footprint

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If feed stalks are positioned vertically for simple construction, then manufacturing ease is improved, but lateral spacing between adjacent columns increases beyond compact design requirements

Engineering Contradiction:

Improvefeed stalk installationVSAvoidlateral spacing between columns

Core Design Contradiction:

Ease of manufactureVSArea of moving object

Solution Approach 1:

The feed stalk is deliberately positioned at an asymmetric angled orientation (e.g., 45 degrees from vertical) rather than a simple vertical alignment. This asymmetric configuration, while slightly more complex than vertical positioning, enables compact lateral arrangement of multiple linear arrays by utilizing the oblique angle to achieve both vertical support and lateral offset in a single structural element

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The angled feed stalk serves multiple functions simultaneously: it provides mechanical support for the radiating element, establishes the required lateral offset from the column axis, and defines the orientation of the radiating element. This multi-functionality consolidates what would otherwise require separate components, maintaining ease of manufacture while achieving compact lateral spacing

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11909121B2Radiating elements having angled feed stalks and base station antennas including same

Publication Date: 2024.02.20 OUTDOOR WIRELESS NETWORKS LLC

AI summary

Radiating elements of first and second linear arrays of radiating elements have respective feed stalks that can reside at an angle to provide a balanced dipole arm with an inner end portion laterally offset to be closer to a right or left side of the base station antenna and reflector than an outer end portion that faces a radome of the base station antenna. The feed stalk can include sheet metal legs and printed circuit boards providing an RF transmission line(s).