Wideband Dipole Antenna With Parasitic Capacitive Coupling

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Solution Overview

Problem

Multi-band base station antennas face challenges in meeting performance specifications, especially when using wideband radiating elements, as they can interact in unintended ways, making it difficult to ensure performance across larger frequency ranges.

Innovation Solution

The design incorporates cross-dipole radiating elements with parasitic elements that capacitively couple RF energy between dipole arms, increasing the effective length of the radiating elements for specific frequency ranges while maintaining a compact footprint, thereby enhancing performance across a wide frequency band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If wideband radiating elements are used to support multiple frequency bands, then the frequency range coverage is improved, but the performance specifications become difficult to meet due to unintended interactions between arrays

Engineering Contradiction:

Improvefrequency range coverageVSAvoidperformance specification compliance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The radiating element is segmented into multiple dipole arms (first through fourth dipole arms) arranged in perpendicular pairs, with each pair operating in different frequency bands. This segmentation allows independent optimization of each dipole arm for specific frequency ranges while reducing unwanted interactions between arrays through spatial separation and orthogonal arrangement.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the effective length of dipole arms is increased for lower frequency ranges, then the performance at lower frequencies is improved, but the physical size of the antenna increases

Engineering Contradiction:

Improvelower frequency performanceVSAvoidphysical size

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The antenna structure transitions from a two-dimensional planar arrangement to a three-dimensional configuration with dipole arms extending in multiple spatial dimensions. The first and third dipole arms extend along a first axis while the second and fourth dipole arms extend along a second axis perpendicular to the first axis, allowing effective length extension in multiple directions without proportionally increasing the overall footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Multiple dipole arms are nested within a compact structure where the first through fourth dipole arms are arranged to occupy overlapping or adjacent spatial regions. This nesting allows the effective electrical length to be increased while the physical envelope remains compact, as the dipole arms share common support structures and mounting points.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Adaptability or versatility

If multiple linear arrays of radiating elements are used for multi-band operation, then the number of frequency bands supported is improved, but the arrays interact in unintended ways degrading performance

Engineering Contradiction:

Improvenumber of frequency bandsVSAvoidperformance stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The radiating element employs asymmetric arrangements of dipole arms with different orientations and configurations. The first dipole arm is perpendicular to the second dipole arm, and the third dipole arm is perpendicular to the fourth dipole arm, creating orthogonal pairs that operate in different frequency bands. This asymmetric, orthogonal arrangement minimizes mutual coupling and unwanted interactions between the arrays while maintaining multi-band functionality.

Inventive Principle:

Principle #4Asymmetry

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 design allows for improved performance and efficiency across a wide frequency range, such as 1427-2690 MHz, with minimal increase in physical size, by preferentially increasing the effective length of the dipole arms for lower frequency ranges and maintaining stability at higher frequencies.

Implementation Method 1

a parasitic element having a first conductive segment that is configured to capacitively couple to the first extension of the first dipole arm, a second conductive segment that is configured to capacitively couple to the second extension of the second dipole arm

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS11271305B2Wideband radiating elements including parasitic elements and related base station antennas

Publication Date: 2022.03.08 OUTDOOR WIRELESS NETWORKS LLC

AI summary

A radiating element for a base station antenna includes a first dipole radiator that has a first dipole arm that has a front surface and first and second extensions that project rearwardly from respective side edges of the front surface of the first dipole arm; a second dipole radiator that has a second dipole arm that has a front surface and first and second extensions that project rearwardly from respective side edges of the front surface of the second dipole arm; and a parasitic element having a first conductive segment that is configured to capacitively couple to the first extension of the first dipole arm, a second conductive segment that is configured to capacitively couple to the second extension of the second dipole arm, and a third conductive segment that electrically connects the first conductive segment to the second conductive segment.