Front-End Module Switching for Carrier Aggregation Isolation
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Solution Overview
Problem
Existing front-end modules for mobile terminals fail to ensure adequate cross isolation between multiple communication bands during carrier aggregation (CA) operations, as the configuration with a delay line is unsuitable for maintaining desired isolation characteristics, particularly in systems using both CA and non-CA methods.
Innovation Solution
A front-end module design incorporating a switch module with multiple selection terminals and filters, allowing for switching between different connection states to form attenuation poles in specific frequency bands, thereby enhancing cross isolation between communication bands. This design includes a switch module with a common terminal and multiple selection terminals that switch between different connections, along with filters and impedance matching networks to manage radio-frequency signals across various bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a delay line is directly connected between multiple signal paths for carrier aggregation operation, then cross isolation between communication bands deteriorates
Solution Approach 1:
The delay line connection is segmented into multiple switched segments. Instead of a direct continuous connection, the patent introduces switching elements that divide the delay line into separable sections, allowing selective connection/disconnection based on operational mode (CA or non-CA). This segmentation enables the system to maintain CA capability when needed while preventing cross isolation degradation by disconnecting the delay line in non-CA modes.
Solution Approach 2:
The patent implements dynamic switching of the delay line connection based on operational requirements. Switching elements dynamically connect or disconnect the delay line between signal paths depending on whether the system is operating in carrier aggregation mode or non-CA mode. This dynamic reconfiguration allows the system to adapt its isolation characteristics to match the current operational state, preventing cross isolation deterioration during non-CA operation while maintaining CA functionality.
2Object-affected harmful factors
If switch isolation performance is strengthened to ensure non-CA isolation, then device complexity increases
Solution Approach 1:
The switching elements serve multiple functions: they control both the main signal path selection and the delay line connection status. The same switching mechanism that routes signals between different paths also manages the connection of the delay line, eliminating the need for separate isolation control switches. This multi-functionality reduces overall device complexity while achieving the required isolation performance during non-CA operation.
Solution Approach 2:
The patent introduces switching elements as intermediary components that mediate between the signal paths and the delay line. These intermediaries provide controlled connection points that enable isolation without requiring complex switch configurations. The switching elements act as mediators that can selectively engage or disengage the delay line connection, simplifying the overall switch design while maintaining adequate isolation during non-CA operation.
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
The solution effectively improves cross isolation characteristics during CA operations, ensuring better performance across multiple communication bands, even when both CA and non-CA methods are used, by generating attenuation poles in the frequency bands of overlapping communication bands, thereby enhancing signal integrity and reducing interference.
Implementation Method 1
a third filter that is connected to the first impedance matching network and allows a radio-frequency signal of a third communication band to pass therethrough. When the switch module is in the first state, a first circuit, which includes the third selection terminal, the first impedance matching network, and the third filter, forms an attenuation pole in the frequency band of the second communication band
Data Source
AI summary
A front-end module includes: a switch module that performs CA for bands A and C and performs non-CA for band B, which is located between these two bands, and that has a common terminal and selection terminals; a duplexer that is connected to the selection terminal and allows band A to pass therethrough; a duplexer that is connected to the selection terminal and allows band C to pass therethrough; an impedance matching network that is connected to the selection terminal; and a reception filter that is connected to the impedance matching network and allows band B to pass therethrough. During CA for bands A and C, a first circuit, which includes the impedance matching network and the reception filter, forms an attenuation pole in the frequency band of band C in the transmission characteristic of a path connecting the duplexer, the common terminal, and the duplexer to each other.