Waveguide Antenna Layout With Absorbers for EIRP and Sensitivity

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Solution Overview

Problem

Existing antenna systems face a trade-off between increasing antenna gain for improved receiver sensitivity and adhering to EIRP regulations, where higher gains can exceed regulatory limits, while lower gains compromise sensitivity, and detection accuracy is affected by multiple reflections, especially at close measurement distances.

Innovation Solution

The antenna apparatus incorporates a radio wave absorber on the transmitting path to attenuate transmitted waves and a separate absorber to absorb multiple reflections, while maintaining high receiver sensitivity by positioning these absorbers strategically to avoid obstructing the direct wave paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If antenna gain is increased to improve receiver sensitivity, then receiver sensitivity is improved, but EIRP exceeds regulatory limits

Engineering Contradiction:
Improvereceiver sensitivityVSAvoidEIRP
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent divides the waveguide space into multiple regions by strategically placing radio wave absorbers at specific positions. The first absorber is positioned to affect transmitted waves while the second absorber is positioned to affect reflected waves, creating segmented functional zones within the waveguide structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies radio wave absorbers with specific properties at specific locations within the waveguide. The absorbers are positioned to have different effects on different wave paths - the first absorber on the transmitted wave path and the second absorber on the reflected wave path, creating local quality variations to achieve different functional outcomes.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If antenna gain is decreased to suppress EIRP increase, then EIRP is suppressed, but receiver sensitivity is insufficient

Engineering Contradiction:
ImproveEIRPVSAvoidreceiver sensitivity
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent converts the harmful effect of multiple reflections, which normally degrade detection accuracy, into a beneficial control mechanism. By placing the second radio wave absorber at a specific position, the patent selectively absorbs reflected waves that would otherwise create interference, thereby improving detection accuracy without affecting the main transmitted signal path.

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

3Measurement precision

If radio wave absorber is placed to absorb multiple reflections, then detection accuracy is improved, but direct wave paths may be obstructed

Engineering Contradiction:
Improvedetection accuracyVSAvoiddirect wave obstruction
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent solves the spatial conflict between absorber placement and direct wave paths by utilizing the three-dimensional space within the waveguide. The absorbers are positioned at specific coordinates (first absorber at position P1, second absorber at position P2) that allow them to intercept reflected waves while maintaining clearance from the direct transmission path between the antenna and target.

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 design effectively suppresses EIRP increases, enhances receiver sensitivity, and improves detection accuracy by minimizing multiple reflections, allowing for accurate distance measurement without exceeding regulatory limits.

Implementation Method 1

a first radio wave absorber disposed on the first aperture side in a space surrounded by the first inner wall surface

Methodology Applied
Scientific EffectRadio wave absorption: Absorption (EM radiation)

Implementation Method 2

a lens that controls power distribution at an aperture of the second horn

Methodology Applied
Scientific EffectRadio wave lensing: Lens

Implementation Method 3

a second radio wave absorber disposed inside the waveguide

Methodology Applied
Scientific EffectRadio wave absorption: Absorption (EM radiation)

Data Source

PatentEP4636953A1Antenna device
Publication Date: 2025.10.22 ALPS ALPINE CO LTD
  • EP4636953A1 patent drawingFigure 1A
  • EP4636953A1 patent drawingFigure 1B
  • EP4636953A1 patent drawingFigure 1C

AI summary

An antenna apparatus capable of suppressing an increase in EIRP and achieving good radio wave receiver sensitivity is provided. An antenna apparatus includes a board, an integrated circuit chip including a transmitting antenna and a receiving antenna, the integrated circuit chip being mounted on the board, a waveguide having a first aperture provided on the board side and surrounding the transmitting antenna and the receiving antenna in aperture view, a second aperture provided on a rear side with respect to the first aperture in a radiation direction of the transmitting antenna, and a first inner wall surface connecting the first aperture and the second aperture, a radio wave lens fixed to the second aperture, and a first radio wave absorber disposed on the first aperture side in a space surrounded by the first inner wall surface. At least part of the first radio wave absorber is located inside a first path of a first direct wave that is radiated from the transmitting antenna, directly reaches the radio wave lens, and passes through the radio wave lens, and the first radio wave absorber is located outside a second path of a second direct wave that passes through the radio wave lens and directly reaches the receiving antenna.