Duplexer Using 90° Hybrids for Antenna Mismatch Isolation
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Solution Overview
Problem
Conventional duplexers in mobile communication devices face challenges in achieving good isolation, high selectivity, and decoupling from mismatched antennas, while also requiring reduced space, increased power compatibility, and improved linearity, with existing solutions often requiring multiple hybrids and filters that increase component count and power consumption.
Innovation Solution
A duplexer design utilizing two 90° hybrids and three single filters, with transmit filters configured to reflect receive frequencies and bypass them to ground, reducing component count and space requirements, and incorporating power amplifiers to enhance efficiency and linearity, while maintaining insensitivity to antenna mismatch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional duplexer circuits use multiple hybrids and filters to achieve good isolation and high selectivity, then the isolation and selectivity are improved, but the component count and space requirement increase
Solution Approach 1:
The patent combines the functions of multiple hybrids and filters into a more integrated circuit arrangement. Specifically, it uses a single hybrid combined with a reflector circuit and selective filters to achieve the isolation and selectivity that conventionally required multiple separate components, thereby reducing overall device complexity while maintaining performance
Solution Approach 2:
The hybrid circuit in the patent serves multiple functions simultaneously: it provides signal separation, impedance transformation, and enables the reflector mechanism. This multi-functionality replaces what would traditionally require multiple dedicated components, reducing the total component count while achieving good isolation and high selectivity
2Reliability
If conventional duplexers use multiple hybrids and filters, then good isolation is achieved, but the space requirement increases
Solution Approach 1:
The patent merges multiple functional components into a compact integrated circuit layout. The hybrid, reflector, and filters are arranged in a space-efficient configuration that achieves the required isolation performance without requiring the physical space that would be needed for multiple separate hybrid and filter assemblies
Solution Approach 2:
The circuit elements are arranged in a nested or layered configuration where components are positioned to utilize available space efficiently. The reflector and filters are integrated into the hybrid circuit structure, allowing for compact packaging while maintaining the electrical performance needed for good isolation
3Reliability
If conventional duplexers use impedance matching circuits to achieve good isolation, then isolation is improved, but power consumption increases
Solution Approach 1:
The patent replaces active impedance matching circuits that would require power consumption with a passive reflector-based mechanism. The reflector uses reactive components to create signal cancellation paths that achieve isolation without requiring active power amplification or adjustment, thereby reducing power consumption while maintaining good isolation performance
Data Source
AI summary
A duplexer having good insulation, small geometric dimensions and good decoupling of the transmit signal path from an antenna which may have poor matching is specified. To that end, the duplexer comprises two transmit filters, a receive filter and two 90° hybrids.