Hybrid-Coupler RF Multiplexer for Multi-Band Isolation
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Solution Overview
Problem
Existing RF multiplexers are costly, cumbersome, and inefficient, particularly in supporting multiple frequency bands with high isolation and low insertion loss, which is challenging for modern wireless communication systems requiring carrier aggregation and multi-standard operations.
Innovation Solution
The use of hybrid-coupler-based RF multiplexers with specific configurations of quadrature hybrid couplers and band-pass filters, along with additional passive networks and impedance matching, enables efficient separation and isolation of multiple frequency bands, reducing insertion loss and distortion, and allowing for modular and scalable designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RF multiplexers are used to support multiple frequency bands, then frequency band separation is achieved, but the system becomes costly and cumbersome with high insertion loss
Solution Approach 1:
The RF multiplexer is divided into multiple functional modules, each handling a specific frequency band. Each module contains a hybrid coupler and band-pass filter combination that independently processes one frequency band, allowing signals to be segmented and routed through optimal paths for each band, thereby reducing overall insertion loss while maintaining reliable separation
Solution Approach 2:
Hybrid couplers are introduced as intermediary components between the signal source and band-pass filters. These couplers enable signals to be distributed to multiple filters simultaneously with proper phase relationships, allowing frequency bands to be separated without direct high-loss connections between filters and improving overall energy efficiency
2Reliability
If conventional RF multiplexers are used to support multiple frequency bands, then frequency band separation is achieved, but the device complexity and cost increase
Solution Approach 1:
The hybrid coupler-based module serves multiple functions simultaneously: it performs signal distribution, phase shifting, and impedance matching while feeding multiple band-pass filters. This multi-functionality reduces the need for separate components for each function, simplifying the overall device structure and reducing cost while maintaining reliable frequency band separation
Solution Approach 2:
Multiple band-pass filters are combined in parallel configurations fed by a common hybrid coupler structure. This merging approach allows multiple frequency bands to be handled by a unified modular architecture rather than requiring separate independent filter chains, thereby reducing device complexity and component count while achieving reliable multi-band separation
3Adaptability or versatility
If conventional RF multiplexers are used for carrier aggregation, then multiple frequency bands are supported, but isolation between bands is insufficient
Solution Approach 1:
Each band-pass filter in the multiplexer is designed with optimized local characteristics tailored to its specific frequency band, including Q-factor optimization and impedance matching specific to that band. This local quality optimization ensures that each filter provides maximum isolation for its assigned band while maintaining passband performance, thereby achieving superior inter-band isolation for carrier aggregation applications
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 solution provides low-cost, compact, and highly selective RF multiplexers that support multiple frequency bands with minimal performance degradation, meeting the requirements of commercial wireless communication standards and enabling efficient carrier aggregation and multi-standard operations.
Implementation Method 1
hybrid-coupler-based RF multiplexers with specific configurations of quadrature hybrid couplers and band-pass filters
Implementation Method 2
quadrature hybrid couplers
Implementation Method 3
band-pass filters
Implementation Method 4
impedance matching
Data Source
AI summary
A radio frequency (RF) multiplexer includes, for example, a common port, a first port for a first frequency band, a second port for a second frequency band, and a third port for a third frequency band. The RF multiplexer also includes, for example, a first quadrature hybrid coupler (QHC), a second QHC and a third QHC. A coupling of the first QHC, a first pair of filters, and the second QHC separates the first frequency band and the second frequency band from the common port to the first port and to the second port, respectively. A coupling of the first QHC, a second pair of filters, and the third QHC separates the first frequency band and the third frequency band from the common port to the first port and to the third port respectively.