Intermediate Transition for Antenna to Coplanar Waveguide Impedance Matching

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Solution Overview

Problem

Existing methods for coupling an antenna to a coplanar waveguide (CPW) transmission line in solid-state microwave ovens face challenges in efficient power transmission and impedance matching, leading to potential damage from reflected power and heat dissipation.

Innovation Solution

The implementation of an intermediate transition structure between the antenna and the CPW transmission line, utilizing rectangular metal boundaries with different dielectric sections to minimize field discontinuity and maintain impedance matching, allowing direct connection without coaxial connectors, thereby reducing electromagnetic losses and heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If an antenna is placed close to a coplanar waveguide transmission line, then the overall device size is reduced, but signal integrity deteriorates due to coupling effects and impedance mismatch

Engineering Contradiction:
Improvedevice sizeVSAvoidsignal integrity
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

A transition structure is introduced as an intermediary element between the antenna and coplanar waveguide transmission line. This transition structure includes a feed line with gradually changing geometry that mediates the electromagnetic coupling between the antenna and transmission line, reducing harmful coupling effects while maintaining compact dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The geometry of the feed line is designed with gradually changing parameters (width, spacing, height) along its length. This continuous parameter change enables smooth impedance transformation and reduces reflections, thereby maintaining signal integrity while allowing closer placement of components.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a transition structure is added between the antenna and coplanar waveguide transmission line, then signal integrity is improved, but device complexity increases

Engineering Contradiction:
Improvesignal integrityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The transition structure is merged with the coplanar waveguide transmission line by using the same fabrication process and material system. The feed line is formed as an integrated part of the coplanar waveguide structure, eliminating the need for separate transition components and reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The feed line serves multiple functions: it acts as both the transmission line connecting the antenna to the amplifier and as the impedance matching transition structure. This multi-functionality eliminates the need for separate matching networks, simplifying the overall device architecture.

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

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 enables efficient and safe power transmission by maintaining impedance matching and reducing heat dissipation, preventing damage from reflected power and enhancing the overall performance of the microwave oven.

Implementation Method 1

designed to reduce coupling effects and improve impedance matching between the antenna and the coplanar waveguide transmission line

Methodology Applied
Scientific EffectImpedance matching: Electrical Impedance Tomography

Data Source

PatentEP3520569B1Intermediate transition between an antenna and a coplanar waveguide transmission line of a solid state amplifier
Publication Date: 2022.11.16 WHIRLPOOL CORP
  • EP3520569B1 patent drawingFigure 1
  • EP3520569B1 patent drawingFigure 2
  • EP3520569B1 patent drawingFigure 3~6

AI summary

A microwave oven having an enclosed cavity is provided including an RF signal generator; a solid state amplifier comprising a coplanar waveguide transmission line, the amplifier coupled to the RF signal generator for receiving and amplifying the RF signals generated thereby; an intermediate transition including: a metal boundary having a first section and a second section having different dimensions than that of the first section; a first dielectric disposed in the first section; a second dielectric disposed in the second section; and a center conductor extending from a first side of the substrate to a second side of the substrate through the first and second dielectrics, where a first end of the center conductor is connected to an output of the amplifier; and an antenna coupled to a second end of the center conductor for receiving the amplified RF signals and introducing electromagnetic radiation into the cavity.