Coaxial-Coplanar Microwave Adapter Using Elastic Insulating Film
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Solution Overview
Problem
Existing microwave transitions from coaxial lines to coplanar lines suffer from high reflection and transmission loss, as well as poor mechanical and thermal decoupling, making them inadequate for broadband applications.
Innovation Solution
A broadband microwave transition is achieved using a metallized elastic insulating film to connect the coaxial inner conductor to the coplanar line system, ensuring continuous field transition with minimal reflection and allowing for mechanical and thermal decoupling, where the film is fixed to the outer conductor housing for heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sleeve-like contact shoe is used to connect the coaxial inner conductor to the coplanar center conductor, then mechanical connection is achieved, but strong reflections and poor adaptation occur in broadband applications
Solution Approach 1:
The patent changes the geometric parameters of the transition region by using a tapered coplanar conductor that gradually transforms the field distribution from coaxial to coplanar configuration. This continuous parameter change minimizes discontinuities and reduces reflections, achieving broadband adaptation while maintaining mechanical connection through the elastic film support structure.
Solution Approach 2:
The elastic insulating film with metallized surface acts as an intermediary element between the coaxial inner conductor and the coplanar center conductor. This intermediate structure provides both mechanical support and electrical connection, enabling smooth field transformation while maintaining decoupling between the two systems.
2Device complexity
If the inner conductor of the coaxial line is greatly tapered and placed directly on the center conductor of the coplanar line system, then connection is simplified, but mechanical and thermal decoupling is poor
Solution Approach 1:
The elastic insulating film serves as a thermal intermediary that mechanically connects the coaxial inner conductor to the coplanar center conductor while thermally isolating them. The film's low thermal conductivity prevents heat transfer from the coplanar line system to the coaxial conductor, achieving thermal decoupling without complicating the mechanical connection structure.
Solution Approach 2:
The patent uses a thin elastic insulating film with metallized surface as a flexible intermediary layer that provides mechanical connection while maintaining thermal isolation. The film's flexibility allows for tolerance compensation and mechanical compliance, while its insulating properties ensure thermal decoupling between the coaxial and coplanar systems.
3Stability of the object's composition
If rigid connection structures are used between coaxial and coplanar systems, then mechanical stability is improved, but thermal heating of the coplanar line system increases
Solution Approach 1:
The elastic insulating film provides mechanical stability through its tensile strength and elastic properties while simultaneously preventing thermal heating by blocking heat transfer from the coplanar line system to the coaxial conductor. The film's flexibility also allows for stress relief and tolerance compensation, maintaining mechanical stability without rigid constraints.
Solution Approach 2:
The insulating film acts as a thermal mediator that mechanically couples the coaxial inner conductor to the coplanar center conductor while thermally decoupling them. This intermediary structure prevents heat from the coplanar line system from transferring to the coaxial conductor, reducing thermal heating while maintaining mechanical stability.
4Reliability
If precise manufacturing tolerances are required for the transition section, then transition performance is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent employs a tapered transition design where the coplanar conductor width gradually changes from the coaxial inner conductor diameter to the final coplanar center conductor width. This continuous parameter change creates a broadband matching structure that is tolerant to manufacturing variations, achieving good transition performance without requiring extremely precise tolerances.
Solution Approach 2:
The elastic insulating film provides excessive mechanical compliance and tolerance compensation, allowing the rigid metal components to be manufactured with standard tolerances. The film's elasticity absorbs dimensional variations and misalignments, maintaining good electrical performance without requiring precision manufacturing of all components.
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 provides a low-reflection, low-attenuation transition with effective mechanical and thermal decoupling, enabling efficient connection between coaxial and coplanar lines while allowing for precise manufacturing and adaptable design.
Implementation Method 1
the connection between the inner conductor of the coaxial line and the center conductor of the coplanar line system is made via a piece of film made of elastic insulating material that is metallized on one or both sides
Implementation Method 2
heat can dissipate via the planar inner conductor to the outer conductor and heating of the coplanar line system is avoided
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
In a microwave adapter joining a coaxial conductor (1) to a coplanar conductor system (3), the round inner conductor (4) of the coaxial conductor (1) continues in a longitudinal through hole (5) of an external conductor housing (6) into a planar inner conductor in the form of a narrow film piece (9), metallized at least on one side and made of elastically compliant insulator material. The end of this planar inner conductor (9, 10) subsequently narrows in a transition section (16) to the width of a coplanar central conductor (13; 20) with coplanar earth surfaces (14, 15; 21, 22) on both sides.