Compact Box Dipole Antenna Feed Layout for Wider Azimuth HPBW

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Solution Overview

Problem

Conventional box dipole radiating elements in base station antennas suffer from undesirable radiation patterns due to monopole operation, resulting in narrowed azimuth Half Power Beam Width and rising 'shoulders' in the radiation pattern, which degrade overall antenna performance.

Innovation Solution

A compact quad arrangement of coplanar radiating arms configured for slant-polarized radiation, with in-series inductors integrated into the radiating arms to maintain electrical length and reduce size, and a feed signal routing substrate with high isolation signal traces and ground plane segments to manage RF signals efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional box dipole radiating elements are used with feed stalks at corners, then the antenna structure is simple and easy to manufacture, but the radiation pattern deteriorates with narrowed azimuth HPBW and rising shoulders

Engineering Contradiction:

Improveease of manufactureVSAvoidradiation pattern quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent extracts and removes the problematic feed stalks from the corner positions of the box dipole radiating element. By eliminating these feed stalks that cause monopole operation and unwanted common mode currents, the radiation pattern quality is improved while maintaining manufacturing simplicity through the use of alternative feed mechanisms such as probe feeds through the radiating arms.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of feeding the box dipole at the corners as in conventional designs, the patent inverts the feeding approach by using probe feeds through the radiating arms at positions that avoid corner excitation. This inversion of the feeding location prevents the generation of common mode currents on feed stalks and eliminates the monopole radiation components that cause pattern degradation.

Inventive Principle:

Principle #13The other way round (Inversion)

2Device complexity

If common mode currents are allowed to flow on feed stalks, then the antenna structure remains simple, but the azimuth HPBW is narrowed and radiation shoulders increase

Engineering Contradiction:

Improvedevice complexityVSAvoidazimuth HPBW

Core Design Contradiction:

Device complexityVSLength of moving object

Solution Approach 1:

The patent converts the harmful effect of common mode currents by designing the feeding structure to inherently prevent their generation. By using probe feeds through the radiating arms rather than corner-fed stalks, the design eliminates the source of common mode currents while maintaining structural simplicity, thus benefiting from the absence of these harmful currents without adding complexity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If conventional box dipole elements are used, then manufacturing is easier, but antenna performance degrades due to monopole radiation

Engineering Contradiction:

Improveease of manufactureVSAvoidantenna performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by modifying specific local regions of the box dipole structure - particularly the feeding locations and configurations of individual radiating arms - while maintaining the overall simple box dipole structure. This localized modification eliminates monopole radiation issues without requiring complete redesign of the entire antenna structure, preserving ease of manufacture while improving performance.

Inventive Principle:

Principle #3Local quality

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

The solution reduces undesirable radiation 'shoulders' in the azimuth plane, improving antenna performance by maintaining a wider azimuth Half Power Beam Width and enhancing the overall radiation pattern efficiency.

Implementation Method 1

with in-series inductors integrated into the radiating arms to maintain electrical length and reduce size

Methodology Applied

Scientific EffectInductance: Inductor

Implementation Method 2

configured for slant-polarized radiation, with in-series inductors integrated into the radiating arms

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 3

a feed signal routing substrate with high isolation signal traces and ground plane segments to manage RF signals efficiently

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12199345B2Base station antennas having compact dual-polarized box dipole radiating elements therein that support high band cloaking

Publication Date: 2025.01.14 OUTDOOR WIRELESS NETWORKS LLC

AI summary

A box dipole radiating element uses a compact quad arrangement of substantially coplanar radiating arms to support slant-polarized radiation, in response to differential-mode currents generated along four sides thereof and in response to common-mode currents, which may be generated in substantially the same plane as the differential-mode currents. A feed signal routing network is provided, which includes a feed signal routing substrate on portions of the radiating arms, first through fourth signal traces on a forward face of the substrate, and first through fourth ground plane segments on a rear face of the substrate. These first through fourth ground plane segments are capacitively coupled to the radiating arms. Each of the signal traces receives a corresponding feed signal, and spans a corresponding air gap between a pair of the radiating arms.