RF Front-End Filter Layout for Low-Loss Multiband Signal Paths
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Solution Overview
Problem
Conventional radio-frequency front-end modules face challenges in maintaining low-loss signal propagation characteristics when supporting multiple frequency bands, particularly due to deteriorated filter characteristics and increased insertion loss, which hinders miniaturization and efficiency in multiband and multimode communication devices.
Innovation Solution
A radio-frequency front-end circuit configuration that includes separate band pass filters and band elimination filters, where the band elimination filters are connected in series to define a pass band for one frequency band and act as stop bands for others, ensuring electrical independence and reducing insertion loss, allowing for miniaturization and simplified manufacturing by eliminating the need for multiple band pass filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If band pass filters and band stop filters are connected in common to share input and output terminals, then the number of filters can be reduced, but the filter characteristics deteriorate and insertion loss increases
Solution Approach 1:
The invention divides the filter system into independent signal paths. Each band pass filter has its own dedicated input terminal, and each band stop filter has its own dedicated output terminal. This segmentation prevents mutual interference between filters while maintaining a reduced overall filter count, resolving the contradiction between device complexity and reliability.
2Adaptability or versatility
If multiple band stop filters are added to support increased number of bands, then multiband support capability is improved, but the device size increases and miniaturization becomes difficult
Solution Approach 1:
The invention makes each filter component serve multiple functions. Band pass filters and band stop filters are designed to handle multiple frequency bands simultaneously through their respective pass bands and stop bands. This multi-functionality allows the system to support an increased number of bands without proportionally increasing the number of filter components, enabling miniaturization while maintaining multiband support capability.
3Reliability
If radio-frequency signals pass through multiple filters in sequence, then signal filtering capability is improved, but insertion loss increases and propagation characteristics deteriorate
Solution Approach 1:
The invention optimizes the local quality of each filter component by providing dedicated input terminals for band pass filters and dedicated output terminals for band stop filters. This configuration ensures that each filter operates at its optimal performance point with minimal insertion loss, while the overall system maintains strong signal filtering capability across multiple frequency bands.
Data Source
AI summary
A radio-frequency front-end circuit includes first and second filters, and first and second band elimination filters. The first filter is connected between an antenna common terminal and a first input-output terminal, and has a first frequency band as a pass band. The second filter is connected between the antenna common terminal and a second input-output terminal, and has a second frequency band as a pass band. The first band elimination filter is connected between the antenna common terminal and a third input-output terminal, and has the first frequency band as a stop band. The second band elimination filter is connected in series with the first band elimination filter between the antenna common terminal and the third input-output terminal, and has the second frequency band as a stop band.