Radar Waveguide Coupling Using a Separate Dielectric Waveguide

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Solution Overview

Problem

Existing radar sensors for motor vehicles face challenges in efficiently coupling microwave signals between high-frequency modules and hollow conductor structures due to manufacturing tolerances and the need for complex adjustment networks, especially when different execution variants are produced.

Innovation Solution

The use of a dielectric wave conductor separate from the circuit board allows for independent wave line properties, reducing susceptibility to manufacturing tolerances and enabling optimized coupling to both the hollow conductor structure and the high-frequency module without altering the circuit board.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coupling device is formed as a hole through the circuit board with metallized surfaces, then microwave signal transmission is enabled, but the transmission properties are highly sensitive to manufacturing tolerances and surface roughness, requiring complex matching networks

Engineering Contradiction:
Improvetransmission propertiesVSAvoidmanufacturing tolerances
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The coupling device is divided into three separate segments: a first coupling element on the waveguide structure side, a second coupling element on the radio-frequency component side, and a dielectric component connecting them. This segmentation isolates the coupling mechanism from the circuit board, eliminating sensitivity to board manufacturing tolerances and metallization quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A dielectric component is introduced as an intermediary element between the first and second coupling elements. This dielectric mediator enables microwave signal transmission without requiring metallized surfaces or precise circuit board holes, thereby eliminating the problematic sensitivity to manufacturing tolerances while maintaining reliable transmission properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If different versions of radar sensors are produced with different waveguide structures and high-frequency components, then product versatility is achieved, but the circuit board and coupling device must be adapted for each version, increasing device complexity

Engineering Contradiction:
Improveproduct versionsVSAvoidcircuit board adaptation
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The dielectric component serves as a universal coupling mechanism that can accommodate different versions of waveguide structures and radio-frequency components. By decoupling the transmission function from the circuit board, the same basic coupling design can be used across multiple product variants, reducing the need for version-specific adaptations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The coupling device is designed with adjustable parameters including the geometry of coupling elements and the dielectric constant of the dielectric component. This dynamic design allows optimization for different radar sensor versions without requiring fundamental redesign of the circuit board or coupling structure.

Inventive Principle:
Principle #15Dynamics

3Volume of moving object

If the waveguide structure and radio-frequency component are located on opposite sides of the circuit board, then compact integration is achieved, but the coupling device requires transmission through or around the circuit board, increasing loss

Engineering Contradiction:
Improveintegration compactnessVSAvoidmicrowave signal loss
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The dielectric component acts as an intermediary transmission medium that enables direct coupling between opposite sides of the circuit board without requiring signal transmission through the board substrate or via surface paths. This eliminates the energy losses associated with circuit board transmission while maintaining compact integration.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution allows for efficient microwave signal transfer with reduced loss, providing greater constructive freedom and simplifying the adaptation process across different radar sensor variants.

Implementation Method 1

Dielectric waveguides are conductors made of a dielectric material in which the microwaves can only propagate within the conductor due to refraction and/or reflection.

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

Dielectric waveguides are conductors made of a dielectric material in which the microwaves can only propagate within the conductor due to refraction and/or reflection.

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4402503B1Radar sensor having waveguide structure
Publication Date: 2025.04.09 ROBERT BOSCH GMBH
  • EP4402503B1 patent drawingFigure 1~2
  • EP4402503B1 patent drawingFigure 3~4
  • EP4402503B1 patent drawingFigure 5~6

AI summary

The invention relates to a radar sensor having a waveguide structure (14) and a high frequency module (12), which are arranged on opposite sides of a circuit board (10), and having a coupling device (18) for transferring microwave signals between the high frequency module (12) and the waveguide structure (14), the coupling device (18) having a dielectric waveguide (28) produced separately from the circuit board (10).