Front-end Circuit Band Aggregation Using Segmented Antenna Feeds
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Solution Overview
Problem
Current front-end circuits for LTE fail to support band aggregation modes without performance degradation, requiring additional components and increased area due to the need for simultaneous matching of duplexers and switches, leading to RF losses and design challenges.
Innovation Solution
The design employs multiple antenna feeds, each assigned to a separate frequency range, with duplexers coupled directly or via an antenna switch, allowing for simultaneous operation of multiple frequency bands without additional matching, reducing insertion losses and enabling flexible support for various band combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single-feed antenna with multi-throw switch is used to connect duplexers, then the front-end circuit can be compact, but the switch cannot support two active paths simultaneously and the duplexers cannot be matched without losses
Solution Approach 1:
The patent divides the single antenna feed into multiple separate antenna feeds (first antenna feed and second antenna feed). Each duplexer is connected to a dedicated antenna feed, eliminating the need for complex switching and matching between duplexers sharing a single feed. This segmentation allows simultaneous operation of multiple duplexers without mutual loading effects.
2Adaptability or versatility
If duplexers are matched simultaneously to a single antenna feed, then band aggregation can be supported, but additional area and complexity are required for matching components
Solution Approach 1:
The patent assigns each duplexer to a separate antenna feed, eliminating the need for complex matching networks between duplexers. Each duplexer operates independently on its dedicated feed, simplifying the overall circuit design while supporting multiple band aggregations.
Solution Approach 2:
The patent designs the front-end circuit to support multiple band aggregation modes (e.g., Band 1 + Band 3, Band 1 + Band 5, Band 3 + Band 5) using the same hardware architecture. The circuit can flexibly switch between different band combinations without requiring additional matching components for each mode.
3Adaptability or versatility
If existing front-end supports multiple band combinations, then versatility is improved, but the design becomes challenging and prone to yield loss
Solution Approach 1:
By providing separate antenna feeds for different frequency ranges, the patent simplifies the design of each feed path. Each path can be independently optimized and tested, reducing design complexity and improving manufacturing yield compared to designing a single complex path supporting all band combinations.
4Loss of energy
If single duplexer has extremely good out-of-band reflectivity, then duplexers do not load each other, but this increases component requirements and area
Solution Approach 1:
The patent eliminates the problem of duplexer loading by providing separate antenna feeds for each duplexer. Since each duplexer operates on its own dedicated feed, there is no mutual loading effect regardless of out-of-band reflectivity. This removes the requirement for extremely high reflectivity components.
Data Source
AI summary
A front-end circuit for a wireless communication unit includes at least two antenna feeds. At least one of the antennas is coupled to an antenna switch. The circuit comprises filters and duplexers and is prepared to operate a number of FDD frequency bands. Each FDD band comprises an Rx band for receive signals and a Tx band for transmit signals. The circuit provides a single band operation mode for each frequency band and aggregated band operation modes. In an aggregated band operation mode Rx signals can be received in two different frequency bands at the same time as well as Tx signals can be transmitted in at least one of the two different frequency bands. In addition, TDD bands as well as GSM bands are covered.