MIMO Antenna Reflector Layout for Grating Lobe Mitigation

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Solution Overview

Problem

Existing wireless communication systems face challenges in effectively mitigating grating lobes and interference in massive multiple-input multiple-output (mMIMO) antennas, which are crucial for 5G and beyond networks.

Innovation Solution

The implementation of antenna panels with different boresight directions, equipped with metallic plates or reconfigurable intelligent surfaces, to reflect and attenuate signals, thereby reducing grating and side lobes, and employing beam scaling and phase selection for coherent superposition to enhance directivity and suppress interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If antenna elements are spaced more than half a wavelength apart to accommodate enhanced directivity, then directivity is improved, but grating lobes and interference are generated

Engineering Contradiction:
ImprovedirectivityVSAvoidgrating lobes and interference
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent introduces reflector panels that capture and redirect the energy from grating lobes back toward the main beam direction. The harmful grating lobe radiation is reflected by metallic surfaces positioned at specific angles, converting what would be wasted energy into constructive interference that enhances the main beam strength and suppresses sidelobes.

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

Solution Approach 2:

Reflector panels serve as intermediary elements between the antenna elements and the radiation pattern. These passive reflective surfaces mediate the interaction between the spaced antenna elements and the far-field radiation, enabling coherent superposition in the main beam direction while suppressing grating lobes without requiring active signal processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If multiple antenna panels with different boresight directions are used to enhance coverage, then coverage area is improved, but beam interference increases

Engineering Contradiction:
Improvecoverage areaVSAvoidbeam interference
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

Each antenna panel is equipped with reflectors tailored to its specific boresight direction and operational characteristics. The reflector geometry, position, and orientation are locally optimized for each panel's coverage sector, enabling independent control of radiation patterns and interference mitigation for each panel while maintaining overall system coverage.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If antenna panel spacing is increased to reduce mutual interference, then interference is reduced, but directivity and signal power are degraded

Engineering Contradiction:
Improvemutual interferenceVSAvoiddirectivity and signal power
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The patent transitions from solving the interference problem in the horizontal plane only to utilizing three-dimensional spatial arrangement. Reflectors are positioned at specific heights and angles relative to antenna panels, creating vertical and angular dimensions for interference management. This 3D configuration enables coherent signal combination while suppressing grating lobes through precise geometric positioning.

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 approach enhances signal power and reduces power consumption by mitigating interference and grating lobes, improving the performance of future wireless networks.

Implementation Method 1

At least one antenna panel within the two or more antenna panels may be configured to reflect signals emitted by the two or more antenna panels

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

the at least one antenna panel may be further configured to attenuate the reflected signals

Methodology Applied
Scientific EffectAttenuation: Absorption (EM radiation)

Implementation Method 3

the at least one antenna panel may be further configured to scatter the reflected signals in a plurality of directions

Methodology Applied
Scientific EffectScattering: Scattering

Data Source

PatentEP4586402A1Antenna with reflectors for MIMO radio units
Publication Date: 2025.07.16 NOKIA SOLUTIONS & NETWORKS OY
  • EP4586402A1 patent drawingFigure 1~3
  • EP4586402A1 patent drawingFigure 4~5
  • EP4586402A1 patent drawingFigure 6~7

AI summary

The present disclosure relates to an apparatus (200, 300, 400). The apparatus comprises: Two or more antenna panels (201, 301, 401, 501) with different boresight directions comprising a plurality of antenna elements (504a, 504b, 504c, 504d). At least one antenna panel within the two or more antenna panels is configured to reflect signals emitted by the two or more antenna panels. At least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: Mitigating interference of beams corresponding to the two or more antenna panels.