Vehicle Radar Sensor Assembly RF Interconnect

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Solution Overview

Problem

Current methods for coupling radio frequency (RF) signals between printed wiring boards (PWBs) face challenges such as implementation complexity, reliability concerns, and high costs, particularly in high-frequency applications, due to the need for precise assembly and additional components like coaxial cables or flex circuits.

Innovation Solution

A support structure with recesses is used to mount RF transmitter and receiver circuit boards, creating electrically sealed cavities that reduce RF leakage and cross-talk, and incorporates a waveguide transmission line for efficient signal coupling between boards, eliminating the need for additional hardware and coatings that can attenuate signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If coaxial cable connection is used to couple RF signals between PWBs, then high level of performance is achieved, but implementation complexity and assembly precision requirements increase

Engineering Contradiction:
ImproveRF signal coupling performanceVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the RF signal coupling function directly into the support structure by forming conductive regions that extend from the first PWB through the support structure to the second PWB. This eliminates the need for separate coaxial cables and connecting pins, merging multiple components into a unified structure that reduces assembly complexity while maintaining RF performance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The support structure acts as an intermediary element that provides both mechanical support and RF signal transmission. The conductive regions within the support structure serve as the RF coupling medium, replacing the traditional coaxial cable intermediary while simplifying the overall assembly

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If flex circuit is used to interconnect PWBs, then fewer parts are required, but electrical seal quality and isolation levels deteriorate

Engineering Contradiction:
Improvepart countVSAvoidelectrical seal quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent combines the support structure with integrated conductive regions that provide both mechanical support and electrical connection. This unified approach eliminates the need for separate flex circuits while achieving superior electrical sealing through the continuous conductive path formed by the conductive regions extending through the support structure

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The support structure employs composite construction with conductive regions integrated into the support material. This composite approach enables the structure to simultaneously provide mechanical support, electrical connection, and RF shielding functions that were previously requiring separate components

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If conformal coating is applied over RF circuits, then environmental protection is improved, but signal attenuation increases

Engineering Contradiction:
Improveenvironmental protectionVSAvoidRF signal attenuation
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent extracts the RF circuits and components from direct exposure to the environment by placing them inside sealed cavities formed within the support structure. This eliminates the need for conformal coatings on the RF circuits themselves, as the cavities provide the environmental barrier, thereby avoiding the signal attenuation that would result from coating application

Inventive Principle:
Principle #2Taking out (Extraction)

4Volume of moving object

If transmitter and receiver antennas are mounted close together, then compact design is achieved, but RF leakage and cross-talk increase

Engineering Contradiction:
Improvemodule compactnessVSAvoidRF cross-talk
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent segments the RF environment by creating separate sealed cavities within the support structure for the transmitter and receiver circuits. These cavities act as isolated compartments that physically separate the antennas while maintaining overall compactness. The segmentation prevents RF energy from one circuit from interfering with the other, eliminating cross-talk despite close proximity

Inventive Principle:
Principle #1Segmentation

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 provides a compact, cost-effective, and reliable RF interconnect that reduces signal losses and environmental exposure, while integrating antenna connections and thermal dissipation within a single structure, enhancing the performance and reliability of radar electronics modules.

Implementation Method 1

the recesses form electrically sealed cavities... Disposing the RF circuits and components in metal cavities serves to further electrically isolate the RF circuits and components from each other thereby reducing the amount of undesired RF leakage signals and cross-talk

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

a portion of a support structure has three sides of a rectangular transmission line integrally formed therein... A fourth wall of the waveguide transmission line, is provided by a conductor which can be provided as a printed circuit conductor

Methodology Applied
Scientific EffectWaveguide transmission: Waveguide

Data Source

PatentEP1804075B1Vehicle radar sensor assembly
Publication Date: 2011.04.20 VALEO RAYTHEON SYSTEMS INC
  • EP1804075B1 patent drawingFigure 1~1A
  • EP1804075B1 patent drawingFigure 2~2A
  • EP1804075B1 patent drawingFigure 3

AI summary

A radar electronics module includes a support structure having a first surface having a plurality of recesses with a transmitter circuit board and a receiver circuit board disposed thereon. The transmitter and receiver circuit boards are disposed over the first surface of the supports structure such that transmitter and receive circuits are disposed in cavities on the support structure. The radar electronics module further includes a digital/power supply circuit printed wiring board (PWB) disposed on a second surface of the support structure and a connector disposed on the support structure. The connector is disposed in such a way that it provides electrical connections for at least one of power signals, analog signals or digital signals between at least two of the digital/power supply PWB, the transmitter circuit board and the receiver circuit board.