Co-Fired Magnetic-Dielectric Assembly for Adhesive-Free RF Isolators
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Solution Overview
Problem
Current methods for forming composite magnetic-dielectric disc assemblies for circulators and isolators are inefficient due to the need for adhesives, which lead to inefficiencies in machining, adhesion issues, and increased complexity in the manufacturing process, particularly when trying to integrate high-frequency components like those required for 5G systems.
Innovation Solution
The development of low temperature fireable dielectric materials with a garnet or scheelite structure that can be co-fired with high dielectric inner materials at temperatures between 650-900°C without adhesives, allowing for the formation of integrated magnetic/dielectric assemblies, such as circulators and isolators, by shrinking the outer material around the inner material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesives are used to form composite magnetic-dielectric disc assemblies, then the components can be assembled, but manufacturing complexity increases and adhesion issues occur
Solution Approach 1:
The patent combines the dielectric material and ferrite material into a single composite ceramic structure through co-firing, eliminating the need for separate assembly steps with adhesives. The dielectric outer layer and ferrite inner core are formed as one integrated component, reducing manufacturing complexity and eliminating adhesion issues.
Solution Approach 2:
The patent uses a composite ceramic material consisting of a dielectric outer layer and a ferrite inner core that are co-fired together. This composite structure integrates multiple functional materials into a single homogeneous component, avoiding the need for adhesive bonding between separate parts.
2Ease of manufacture
If adhesives are used to join dielectric and ferrite components, then assembly is possible, but voids and increased insertion loss occur
Solution Approach 1:
The dielectric and ferrite materials are merged into a single co-fired ceramic structure, eliminating adhesive layers that create voids and insertion loss. The intimate bonding achieved through co-firing ensures continuous material contact without air gaps.
3Manufacturing precision
If conventional high temperature firing is used for dielectric materials, then dielectric properties are achieved, but co-firing with ferrite becomes difficult
Solution Approach 1:
The patent modifies the firing temperature parameter to enable co-firing of dielectric and ferrite materials. By using a lower firing temperature range (900-1100°C) compared to conventional dielectric firing temperatures, both materials can be processed together without degradation, while still achieving the required dielectric properties.
Solution Approach 2:
The invention uses a composite ceramic formulation where the dielectric outer layer is specifically designed to be compatible with ferrite co-firing. This composite material approach allows simultaneous processing of materials with different thermal requirements.
4Ease of manufacture
If adhesives are used in the assembly process, then components can be joined, but machining efficiency decreases
Solution Approach 1:
The dielectric and ferrite components are merged into a single co-fired ceramic piece, eliminating the need for separate joining operations. This integration allows for more efficient machining and processing since the entire assembly is created as one monolithic structure rather than multiple parts requiring assembly.
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 eliminates the need for adhesives, reduces manufacturing complexity, and enables the integration of high-frequency components on a single substrate, improving miniaturization and performance by avoiding the issues associated with adhesive use, such as voids and increased insertion loss.
Implementation Method 1
co-firing the lower temperature fireable outer material and the high dielectric inner material together at temperature between 650-900° C. to shrink the low temperature fireable outer material around an outer surface of the high dielectric inner material
Data Source
AI summary
A method of forming a composite material for use as an isolator or circulator in a radiofrequency device comprises providing a low temperature fireable outer material, the low fireable outer material having a garnet or scheelite structure, inserting a high dielectric constant inner material having a dielectric constant above 30 within an aperture in the low temperature fireable outer material, and co-firing the lower temperature fireable outer material and the high dielectric constant inner material together at temperature between 650-900° C. to shrink the low temperature fireable outer material around an outer surface of the high dielectric constant inner material to form an integrated magnetic/dielectric assembly without the use of adhesive or glue.