RF Module Filter Stacking for Heat Dissipation and Isolation
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Solution Overview
Problem
In radio-frequency modules with stacked transmit and receive filters, the heat dissipation performance of the transmit filter is often degraded, and the isolation between the filters is reduced, leading to compromised performance in communication devices.
Innovation Solution
The design includes a mounting substrate with a transmit filter and a first receive filter on one surface and a second receive filter stacked on top, with non-overlapping pass bands to minimize electromagnetic coupling and enhance heat dissipation by ensuring no filter is directly on the transmit filter, which allows for improved heat dissipation and reduced temperature-induced variations in the receive filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transmit filter and another filter are stacked on each other, then the device complexity is reduced and space is saved, but the heat dissipation performance of the transmit filter is degraded
Solution Approach 1:
The patent transitions from a single-layer filter arrangement to a three-dimensional stacked configuration, but strategically positions filters in different vertical layers to avoid direct overlap with the transmit filter. The second receive filter is placed in a higher layer that does not directly overlap the transmit filter's heat dissipation zone, enabling spatial separation that maintains heat dissipation while achieving compact integration.
Solution Approach 2:
The filter assembly is segmented into multiple functional regions: a first region where the first receive filter overlaps the transmit filter, and a second region where the second receive filter is positioned to avoid overlapping the transmit filter. This segmentation allows different thermal management strategies for different filter types, with receive filters tolerating closer proximity to the transmit filter while the second receive filter maintains better thermal isolation.
2Volume of moving object
If the transmit filter and the receive filter are stacked on each other, then the device size is reduced, but the isolation between the transmit filter and the receive filter is reduced
Solution Approach 1:
The patent utilizes vertical stacking in the third dimension to achieve compact footprint while managing electromagnetic interference. By placing the second receive filter in a higher vertical layer that does not directly overlap the transmit filter's planar projection, the design achieves both miniaturization and maintained isolation through spatial separation in the vertical dimension.
Solution Approach 2:
Different isolation strategies are applied to different receive filters based on their specific requirements. The first receive filter is positioned in a region with acceptable electromagnetic coupling to the transmit filter, while the second receive filter is positioned in a region with better isolation. This local differentiation allows optimization of each receive channel's performance characteristics.
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 configuration maintains the heat dissipation performance of the transmit filter and reduces electromagnetic coupling, thereby enhancing the isolation between filters and improving the overall performance of the radio-frequency module, particularly in communication devices supporting multiple frequency bands.
Implementation Method 1
a first filter using a first communication band as the pass band and a second filter using a second communication band, which is different from the first communication band, as the pass band
Implementation Method 2
the isolation between the transmit filter and the receive filter may be reduced
Data Source
AI summary
A radio-frequency module includes a mounting substrate having a first main surface, an electronic component, and a second receive filter. The electronic component includes a transmit filter and a first receive filter and is disposed on the first main surface of the mounting substrate. The second receive filter is stacked on the electronic component. The pass band of the transmit filter and that of the second receive filter do not exactly match each other. In a plan view in a thickness direction of the mounting substrate, a first region of the electronic component where the first receive filter is located overlaps or matches the second receive filter, and a second region of the electronic component where the transmit filter is located overlaps none of filters disposed on the first main surface of the mounting substrate.