Duplexer Phase Shifter Circuit High Isolation
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Solution Overview
Problem
Existing duplexers for mobile communication devices face challenges in achieving high isolation between transmission and reception signal paths, limiting their ability to meet current and future specifications.
Innovation Solution
A duplexer design incorporating a hybrid with a phase shifter circuit, including a matching element between the transmitting and receiving filters, and using coupled transformers to achieve high isolation, thereby eliminating the need for complex balun circuits and improving signal path isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional matching circuit is used between transmitting and receiving filters, then the duplexer can be assembled, but the isolation between transmission and reception signal paths is insufficient
Solution Approach 1:
A hybrid circuit is introduced as an intermediary component between the transmitting and receiving filters. This hybrid circuit includes a phase shifter that creates a 90-degree phase difference between signal paths, enabling improved isolation without requiring complex matching networks. The hybrid acts as a mediator that transforms the signal distribution to achieve both high isolation and balanced/unbalanced path conversion.
Solution Approach 2:
The invention changes the phase parameter of signals by introducing a 90-degree phase shift through the hybrid circuit's phase shifter. This parameter change enables the transmission and reception signal paths to be orthogonally separated, significantly improving isolation between paths while maintaining a relatively simple circuit structure.
2Adaptability or versatility
If complex balun circuits are used to achieve balanced/unbalanced signal paths, then signal path requirements are met, but device complexity and cost increase
Solution Approach 1:
The invention merges the functions of the hybrid circuit and phase shifter into a single integrated component that simultaneously provides both balanced-to-unbalanced conversion and 90-degree phase shifting. This consolidation eliminates the need for separate balun circuits, reducing overall device complexity while maintaining the required adaptability for balanced and unbalanced signal paths.
Solution Approach 2:
The hybrid circuit is designed to perform multiple functions: it provides balanced-to-unbalanced conversion, introduces a 90-degree phase shift, and enables isolation between transmission and reception paths. This multi-functionality replaces what would traditionally require multiple separate components including baluns, simplifying the overall duplexer design.
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 duplexer achieves significantly improved isolation between signal paths, reducing susceptibility to common-mode interference and meeting stringent isolation specifications with frequency-independent performance exceeding -160 dB, while simplifying the design and reducing costs.
Implementation Method 1
the phase shifter circuit comprises a 0°/90° 3 dB hybrid having four terminals
Implementation Method 2
a phase shifter circuit comprises a 0°/90° 3 dB hybrid having four terminals
Implementation Method 3
The hybrid can comprise coupled transformers
Data Source
AI summary
A duplexer comprising an improved matching circuit for matching between transmitting path and receiving path is specified. In this case, the matching circuit comprises a hybrid and matching elements.