Slot-Fed Patch Antenna Layout for Wideband Polarization Isolation

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Solution Overview

Problem

Dual linear-polarized antenna arrangements face challenges in simultaneously optimizing S-parameters bandwidth and isolation, especially in arrays used for beam steering across various angles.

Innovation Solution

The antenna arrangement features a dual polarized feed arrangement with conductors oriented 90° offset, introducing a 180° phase difference, and a slot-fed patch radiator with a conductive layer and cavity configuration, providing balanced feed and sufficient isolation through a sinuous slot and rotational symmetry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dual linear-polarized antenna arrangements use traditional dipole radiators oriented in orthogonal directions, then the basic antenna function is achieved, but it is difficult to simultaneously optimize S-parameters bandwidth and isolation between radiators

Engineering Contradiction:
Improveisolation between radiatorsVSAvoidS-parameters bandwidth
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The antenna arrangement segments the radiation function by using a slot in a conductive layer instead of traditional dipole radiators. The slot is fed by multiple feed conductors that are galvanically isolated from each other, allowing independent optimization of each feed while maintaining high isolation between orthogonal polarizations. This segmentation enables the S-parameters to achieve wide bandwidth without compromising isolation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The slot in the conductive layer acts as an intermediary between the feed conductors and the radiation function. The slot couples energy from the feed conductors to the patch radiator while maintaining galvanic isolation between the feed lines. This intermediary structure enables wide bandwidth operation while preserving high isolation between orthogonal polarizations, resolving the technical contradiction.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If antenna arrays are used for beam steering across a range of angles, then coverage and versatility are improved, but maintaining sufficient isolation becomes even more difficult

Engineering Contradiction:
Improvebeam steering capabilityVSAvoidisolation between radiators
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The feed arrangement segments the signal paths for different beam steering directions using separate feed conductors that are galvanically isolated. Each feed conductor can be independently controlled for phase and amplitude, enabling beam steering while maintaining isolation between elements. The slot structure further segments the coupling paths, preventing interference between adjacent antenna elements in the array.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from traditional coplanar feed arrangements to a three-dimensional structure where feed conductors are positioned above and below the conductive layer at different heights. This vertical dimensionality provides additional spatial separation and coupling control, enabling beam steering across wide angle ranges while maintaining high isolation between radiators through the combined effect of vertical and horizontal separation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration achieves wide bandwidth and high isolation between polarizations, enabling effective beam steering and side lobe suppression across a range of angles, suitable for massive MIMO and digital beamforming applications.

Implementation Method 1

a slot (30) in a conductive layer (60)... a patch radiator (20)... at an operational frequency band

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

conductive interconnects to the first pair of feed conductors, of different lengths, introduce a 180° phase difference between the first pair of feed conductors

Methodology Applied
Scientific EffectPhase difference:

Data Source

PatentEP3910735B1An antenna arrangement
Publication Date: 2024.03.06 NOKIA SOLUTIONS & NETWORKS OY
  • EP3910735B1 patent drawingFigure 1A~1C
  • EP3910735B1 patent drawingFigure 2A~2B
  • EP3910735B1 patent drawingFigure 3A~3B

AI summary

An antenna arrangement comprising: a patch radiator; a feed arrangement, for the patch radiator; and a cavity for the feed arrangement, wherein the feed arrangement comprises a slot in a conductive layer located between the patch radiator and the cavity.