LC Frontend Module for Neighboring Band Attenuation
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Solution Overview
Problem
Current frontend modules for 5G communications face challenges in providing sufficient attenuation characteristics for neighboring frequency bands, particularly in the sub-6 GHz and 5 GHz Wi-Fi bands, due to limitations in broadband frequency characteristics and the difficulty in implementing Bulk Acoustic Wave filters for wide passbands.
Innovation Solution
The proposed frontend module incorporates a combination of LC filters with Chebyshev filter structures, including multiple parallel and series LC resonance circuits and passive elements like inductors and capacitors, to provide attenuation characteristics across the 3.3 GHz to 4.2 GHz, 4.4 GHz to 5.0 GHz, and 5.15 GHz to 5.95 GHz bands, using sub-filters to ensure adequate isolation and support for multiple wireless communication standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Bulk Acoustic Wave filters are used for wide passbands, then broadband frequency support is improved, but manufacturing difficulty and cost increase significantly
Solution Approach 1:
The filter system is divided into multiple separate filters, each designed for a specific frequency band (first filter for first band, second filter for second band, third filter for third band). This segmentation allows each filter to be optimized for its specific band using conventional manufacturing techniques, avoiding the need to manufacture complex wideband BAW filters while achieving overall broadband support through the combination of multiple narrowband filters.
2Reliability
If multiple filters are added to provide attenuation for neighboring bands, then attenuation characteristics improve, but device complexity increases
Solution Approach 1:
Each filter in the system is designed to perform multiple functions: the first filter provides attenuation for the second and third bands while passing the first band, the second filter provides attenuation for the first and third bands while passing the second band, and the third filter provides attenuation for the first and second bands while passing the third band. This multi-functionality reduces the need for separate attenuation components, simplifying the overall device structure while maintaining excellent attenuation characteristics for all neighboring bands.
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 ensures sufficient attenuation characteristics for neighboring bands, enabling efficient carrier aggregation and reducing the number of antennas needed in mobile devices, while maintaining broadband frequency support and minimizing insertion loss.
Implementation Method 1
the second filter includes a plurality of parallel LC resonance circuits arranged between a ground and different nodes
Implementation Method 2
an inductor is connected to a portion of the plurality of parallel LC resonance circuits
Implementation Method 3
a capacitor is connected to a portion of the plurality of series LC resonance circuits
Data Source
AI summary
A frontend module includes a first filter having a passband of a first frequency band, a second filter having a passband of a second frequency band, the second frequency band being higher than the first frequency band, a third filter having a passband of a third frequency band, the third frequency band being higher than the second frequency band, and a sub-filter, connected to the second filter, configured to provide attenuation characteristics for the first frequency band, wherein the second filter comprises a plurality of parallel LC resonance circuits arranged between a ground and different nodes, from among a plurality of nodes between a first terminal and a second terminal, wherein an inductor is connected to a portion of the plurality of parallel LC resonance circuits.