Circuit Board Structure for LNB Signal Isolation

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Solution Overview

Problem

Conventional Low Noise Block down-converters experience increased return loss and insertion loss due to discontinuous impedances and low isolation between signal paths, leading to signal crosstalk and noise interference, and have complex assembly processes that increase production costs and weight.

Innovation Solution

A circuit board structure with a first and second substrate, where vias and grounded wires form a coplanar waveguide intersection to ensure continuous impedance and reduce crosstalk, using surface mount technology for assembly and spacers to block electromagnetic radiation, adhering to CoPlanar Waveguide principles for optimized signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional LNB structure with multiple circuit boards and thru pins is used, then signal transmission is enabled, but return loss and insertion loss increase due to discontinuous impedances

Engineering Contradiction:
Improvereturn loss and insertion lossVSAvoidcomplex assembly process
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges multiple circuit boards into a single integrated circuit board structure, eliminating the need for multiple thru pins and spacers. This integration ensures continuous impedance throughout the signal path, thereby reducing return loss and insertion loss while simplifying the assembly process.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements continuous impedance through unified ground wires and via holes that span the entire circuit board. This continuity prevents impedance discontinuities at connection points, maintaining signal integrity and reducing energy loss in the RF signal transmission path.

Inventive Principle:
Principle #20Continuity of useful action

2Reliability

If conventional LNB structure with multiple circuit boards is used, then signal processing is enabled, but isolation between signal paths is low causing signal crosstalk

Engineering Contradiction:
Improveisolation between signal pathsVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the circuit board into distinct regions with dedicated ground wires for different signal paths. This segmentation creates isolated zones that prevent electromagnetic coupling between adjacent RF signals, thereby improving isolation and reducing crosstalk while maintaining a simplified overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces ground wires as intermediary elements between different signal paths. These ground wires act as shields that block electromagnetic interference and prevent crosstalk between adjacent RF signals, improving signal isolation without adding significant structural complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional LNB structure with multiple components is used, then signal processing function is achieved, but weight and production cost increase

Engineering Contradiction:
Improvesignal processing functionVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines multiple functional components (LNAs, power dividers, filters, mixers, oscillators) onto a single circuit board, eliminating the need for separate circuit boards, spacers, and multiple thru pins. This merging significantly reduces the overall weight while maintaining complete signal processing functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent designs a universal circuit board structure that performs multiple functions: signal amplification, power division, filtering, mixing, and oscillation all occur on the same board. This multi-functionality eliminates the need for separate components and reduces total weight while preserving full signal processing capability.

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

4Ease of manufacture

If conventional LNB structure with thru pins is used, then signal transmission between circuit boards is enabled, but assembly complexity and production cost increase

Engineering Contradiction:
Improveassembly processVSAvoidsignal transmission efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent extracts and eliminates the thru pins and spacers from the design by integrating all connections directly into the single circuit board structure. This removal of intermediate components simplifies the assembly process to essentially single-board fabrication, while the continuous impedance path maintained by unified ground wires preserves signal transmission efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

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

The solution achieves low insertion losses, high isolation, and reduced return losses, improving signal integrity and reducing production complexity and weight, while enhancing the ability to shield electromagnetic radiation and mitigate crosstalk, thereby improving the Signal-to-Noise Ratio.

Implementation Method 1

A circuit board structure with a first and second substrate, where vias and grounded wires form a coplanar waveguide intersection to ensure continuous impedance and reduce crosstalk

Methodology Applied
Scientific EffectCoplanar Waveguide: Waveguide

Implementation Method 2

spacers to block electromagnetic radiation

Methodology Applied
Scientific EffectElectromagnetic radiation shielding: Faraday Cage

Data Source

PatentEP2747315B1Circuit board structure
Publication Date: 2018.07.04 WISTRON NEWEB CORP
  • EP2747315B1 patent drawingFigure 1
  • EP2747315B1 patent drawingFigure 2
  • EP2747315B1 patent drawingFigure 3

AI summary

A circuit board structure (30) for a low noise block down-converter (10) is disclosed. The circuit board structure (30) is used for transmitting a first radio-frequency signal (SV) and a second radio-frequency signal (SH) across each other, and includes a first substrate (31) and a second substrate (32). The first substrate (31) includes a first wire (L1) for transmitting the first radio-frequency signal (SV), a first grounded wire (G1) formed in parallel to a side of the first wire (L1), and a second grounded wire (G2) formed in parallel to another side of the first wire (L1). The second substrate (32) is electrically connected to the first substrate (31), and includes a second wire (L2) for transmitting the second radio-frequency signal (SH), a third wire (L3) formed on a side of the second wire (L2) and a fourth wire (L4) formed on another side of the second wire (L2).