Offset Coax-to-Microstrip Transition for Low-Loss RF Coupling

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Solution Overview

Problem

Existing coaxial transmission lines experience significant energy loss and increased signal-to-noise ratio when transitioning to micro-strip structures due to discontinuities in electromagnetic field lines, leading to inefficiencies in radio frequency signal transmission.

Innovation Solution

The solution involves offsetting the conductor of the coaxial transmission line to concentrate electromagnetic field lines in a specific direction, allowing for a smooth transition to micro-strip structures using a connector, thereby reducing discontinuities and enhancing energy transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a coaxial transmission line is directly connected to a micro-strip structure, then the connection is simple, but energy loss increases and signal-to-noise ratio deteriorates due to field line discontinuities

Engineering Contradiction:

Improveconnection simplicityVSAvoidenergy loss

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent introduces an asymmetric transition structure where the coaxial connector is offset from the center of the micro-strip line. This asymmetric positioning allows the electromagnetic field lines to transition smoothly from the circular symmetry of the coaxial cable to the planar geometry of the micro-strip, reducing field discontinuities and energy loss while maintaining manufacturing simplicity

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent employs an intermediate transition region that acts as a mediator between the coaxial transmission line and the micro-strip structure. This transition region includes a ground plane and conductive elements that guide the field lines continuously from one structure to the other, preventing energy loss while keeping the overall connection simple

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If a coaxial transmission line is directly connected to a micro-strip structure, then the structure is compact, but signal-to-noise ratio increases due to field line discontinuities

Engineering Contradiction:

Improvestructure compactnessVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The asymmetric offset of the coaxial connector relative to the micro-strip center creates a controlled field distribution that minimizes radiation and noise while maintaining a compact overall structure. The asymmetric geometry guides field lines in a predictable path that reduces electromagnetic interference

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The transition structure with ground plane and conductive elements serves as an intermediary that contains and directs electromagnetic fields, preventing noise radiation while keeping the structure compact. The ground plane acts as a shield that reduces signal-to-noise ratio degradation

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If the conductor is offset from the center of the coaxial transmission line, then energy transfer efficiency improves, but manufacturing precision requirements increase

Engineering Contradiction:

Improveenergy transfer efficiencyVSAvoidconductor positioning precision

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent establishes a specific asymmetric offset distance between the coaxial conductor and the micro-strip center, optimized to maximize energy transfer efficiency. This defined asymmetric geometry provides clear manufacturing guidelines while achieving superior energy transfer compared to centered configurations

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent optimizes the offset distance parameter to balance energy transfer efficiency and manufacturing feasibility. By carefully selecting this geometric parameter, the design achieves high energy transfer efficiency while maintaining tolerances that are practical for standard manufacturing processes

Inventive Principle:

Principle #35Parameter changes

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 minimizes energy loss and signal-to-noise ratio by ensuring a continuous flow of electromagnetic field lines along a single ground plane, improving the transmission efficiency and reducing reflections.

Implementation Method 1

offsetting the conductor of the coaxial transmission line to concentrate electromagnetic field lines in a specific direction

Methodology Applied

Scientific EffectElectromagnetic field concentration:

Implementation Method 2

ensuring a continuous flow of electromagnetic field lines along a single ground plane

Methodology Applied

Scientific EffectElectromagnetic field continuity:

Data Source

PatentUS12444822B2Coaxial transmission line to micro-strip package transition

Publication Date: 2025.10.14 AMPLITECH INC

AI summary

A method for coupling a coaxial transmission line with a micro-strip package transition is disclosed. The method includes offsetting a conductor from a center, of the coaxial transmission line. The offsetting the conductor concentrates a first electromagnetic field lines of the coaxial transmission line towards a single ground plane. Further, the method includes coupling the micro-strip along a length of the offset conductor, using a connector. The first electromagnetic field lines of the offset conductor flows into the micro-strip to transmit energy packets with least discontinuity, for smooth transition of energy packets, with less or minimal signal to noise ratio.