Nested RF Filter Assembly for Compact Multi-Band Duplexers
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Solution Overview
Problem
Current radio-frequency devices face challenges in reducing the size and increasing the functionality of filters, particularly in power amplifier with integrated duplexer (PAiD) modules, where up to 70% of the substrate area is occupied by duplexers, necessitating a reduction in duplexer footprint without increasing costs or compromising manufacturing infrastructure.
Innovation Solution
The implementation of nested filter configurations, where a second filter device is positioned within the space defined by the underside of a first filter device and support structures, including metal and solder structures, to achieve a reduced footprint while maintaining functionality across multiple frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If filters are arranged in a conventional planar layout on the substrate, then the device occupies a large substrate area, but the functionality and frequency band support are maintained
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of filters to a three-dimensional nested configuration where filters are stacked vertically at different heights above the substrate. This dimensional change allows multiple filters to occupy overlapping horizontal footprints while maintaining electrical isolation through vertical separation, thereby reducing the overall substrate area while preserving frequency band support capabilities
Solution Approach 2:
The patent implements a nested filter architecture where a first filter and a second filter are positioned in a nested relationship with the second filter located in the space defined by the underside of the first filter and support structures. This nesting arrangement allows filters to be packed more densely in the vertical dimension, reducing the horizontal footprint while maintaining individual filter functionality across different frequency bands
2Area of stationary object
If the footprint of duplexers is reduced to decrease module size, then the device size is reduced, but manufacturing complexity and structural stability may be compromised
Solution Approach 1:
The patent divides the duplexer structure into segmented components including multiple filters at different heights, support structures, and mounting substrates. This segmentation allows each component to be optimized independently for its specific function while collectively achieving a compact footprint, reducing manufacturing complexity compared to attempting to shrink a monolithic duplexer structure
Solution Approach 2:
By introducing vertical stacking with filters at different heights above the substrate, the patent reduces the horizontal footprint of the duplexer while distributing structural loads across multiple vertical levels. This three-dimensional configuration maintains structural stability despite the reduced footprint, as the vertical support structures provide mechanical reinforcement
3Area of stationary object
If filters are positioned closer together to reduce surface mount area, then manufacturing precision requirements increase, but area reduction is achieved
Solution Approach 1:
The patent uses vertical stacking to separate filters in the height dimension rather than relying solely on horizontal separation. This allows filters to be positioned with smaller horizontal offsets while maintaining adequate isolation through vertical distance, thereby reducing surface mount area without proportionally increasing manufacturing precision requirements in the planar directions
Solution Approach 2:
The patent employs support structures that are pre-configured with mounting features and positioning elements before filter assembly. These pre-fabricated support structures provide precise mechanical guides and alignment features that simplify the positioning process during assembly, reducing the actual manufacturing precision requirements despite the compact nested configuration
4Area of stationary object
If nested filter configuration is implemented to reduce footprint, then area is reduced, but structural stability and support for multiple frequency bands must be maintained
Solution Approach 1:
The patent incorporates pre-fabricated support structures with integrated mounting features and mechanical reinforcement elements before assembling the filters. These support structures are designed in advance to provide the necessary structural stability for the nested configuration, ensuring that the reduced footprint does not compromise the mechanical integrity or the ability to support multiple frequency bands
Solution Approach 2:
The patent employs composite construction combining multiple materials with different mechanical properties in the support structures and filter assemblies. This composite approach allows optimization of each material for specific functions - providing both the structural stability needed for the nested arrangement and the electrical properties required for multi-frequency operation, while maintaining a compact footprint
Data Source
AI summary
Devices and methods related to nested filters. In some embodiments, a radio-frequency device can include a substrate, and first and second filter devices mounted on the substrate with respective support structures, such that at least a portion of the second filter device is positioned in a space defined by an underside of the first filter device and the support structures for the first filter device. Such a radio-frequency device can be, for example, a packaged module for use in an electronic device such as a wireless device.