Two-Antenna System for Interband Carrier Aggregation
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Solution Overview
Problem
Existing RF front ends in radio transceivers face challenges in providing full bandwidth for LTE-Advanced carrier aggregation due to design constraints, leading to limited antenna performance and high insertion loss from quadplexers.
Innovation Solution
A two-antenna system with dedicated antenna matching networks and bandpass filters for each antenna, allowing for reduced bandwidth requirements and improved efficiency by eliminating the need for high insertion loss quadplexers, and enabling better antenna matching without complex tuning networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single antenna is designed with sufficient bandwidth to accommodate both frequency bands, then the antenna can support carrier aggregation, but the physical size of the antenna must be increased and the bandwidth cannot be fully met due to design constraints
Solution Approach 1:
The patent divides the single antenna system into two separate antennas, each optimized for specific frequency bands. The first antenna handles band A and band X, while the second antenna handles band B and band Z. This segmentation allows each antenna to be smaller and more efficiently tuned to its designated bands, while collectively providing full carrier aggregation support across all bands.
2Adaptability or versatility
If duplex filters are combined through diplexing in a single antenna system, then multiple bands can be supported, but insertion loss increases and bandwidth is reduced
Solution Approach 1:
The patent eliminates the need for high-loss diplexed duplex filters by assigning separate antennas to different band groups. Each antenna connects directly to its designated bands through simple switching, avoiding the cascaded filter structure that causes insertion loss. This segmentation of RF paths maintains signal strength while supporting multiple bands.
3Adaptability or versatility
If a quadplexer is used to support PCC and SCC operation in a single antenna system, then carrier aggregation is enabled, but the insertion loss becomes very high
Solution Approach 1:
The patent replaces the single high-loss quadplexer with two separate antennas, each with its own simpler duplexer and band switching. The first antenna handles PCC/SCC for bands A and X, while the second antenna handles PCC/SCC for bands B and Z. This segmentation distributes the filtering function across multiple lower-loss paths, significantly reducing overall insertion loss while maintaining full carrier aggregation capability.
4Loss of energy
If a second antenna is dedicated to the second band all the time, then the need for high insertion loss quadplexers is eliminated, but antenna coupling efficiency degradation occurs
Solution Approach 1:
The patent implements dynamic band switching control that activates the second antenna only when band B or band Z operations are required. The band switching mechanism dynamically connects or disconnects the second antenna based on current carrier aggregation needs, minimizing the time both antennas are simultaneously active and thus reducing coupling efficiency degradation while maintaining low insertion loss benefits.
Data Source
AI summary
A first antenna and a first band switch with a first duplexer operatively coupled to a first output of the first band switch. The first duplexer provides a transmit sub-band feed and a first receive sub-band feed for a first RF band. A second duplexer is operatively coupled to a second output of the first band switch, and provides a transmit sub-band feed and a first receive sub-band feed for a second RF band. A second antenna is operatively coupled to an input of a second band switch. A first antenna matching network for the second antenna is operatively coupled to a first output of the second band switch, and provides a second receive sub-band feed for the first RF band. A second antenna matching network is operatively coupled to a second output of the second band switch, and provides a second receive sub-band feed for the second RF band.