Split-Band Duplexer Architecture for Narrow Duplex Gap Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Full duplex RF communications systems face challenges in providing non-overlapping transmit and receive passbands with minimal insertion loss and sufficient isolation, especially in multi-mode and multi-band wireless systems with narrow duplex gaps, which are exacerbated by manufacturing tolerances and temperature drift.
Innovation Solution
A split-band duplexer architecture that splits the FDD receive and transmit bands into sub-bands, allowing for the use of standard filter components like SAW filters, and dynamically adjusts passbands to support TDD operations, thereby increasing isolation and insertion loss margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single duplexer is used to provide non-overlapping transmit and receive passbands, then isolation between transmit and receive signals is achieved, but insertion loss increases and isolation margins decrease in systems with narrow duplex gaps
Solution Approach 1:
The patent divides a single duplexer function into multiple sub-band duplexers, each handling a specific frequency sub-band. This segmentation allows each sub-band duplexer to be optimized independently, reducing insertion loss within its operating band while maintaining overall isolation through the combined architecture. The segmentation principle directly addresses the contradiction by breaking down the monolithic duplexer into smaller, more efficient units.
2Ease of manufacture
If standard filter components like SAW filters are used, then manufacturing cost and complexity are reduced, but manufacturing tolerances and temperature drift cause degradation in isolation and passband performance
Solution Approach 1:
The patent employs dynamically adjustable passbands in the sub-band duplexers that can adapt to compensate for manufacturing tolerances and temperature drift. This dynamic adjustment capability allows the system to maintain reliable isolation and passband performance despite using standard, cost-effective SAW filters with inherent tolerances. The dynamic tuning counteracts the static limitations of standard components.
3Adaptability or versatility
If the passband is widened to support multiple modes including TDD, then multi-mode functionality is achieved, but isolation between different modes and bands deteriorates
Solution Approach 1:
The patent assigns different local characteristics to different sub-band duplexers, with each optimized for specific frequency ranges and modes. The sub-band duplexers have tailored passband widths and filtering characteristics suited to their specific operating bands. This local optimization allows the overall system to support multiple modes and bands effectively while maintaining isolation, as each local component is designed for its specific function rather than a single broad design attempting to cover all modes.
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 approach enables efficient simultaneous transmission and reception in full duplex modes while reducing insertion loss and maintaining required isolation, even in systems with narrow duplex gaps, by utilizing sub-band duplexers and standard filter components.
Implementation Method 1
standard filter components, such as surface acoustic wave (SAW) filters
Implementation Method 2
surface acoustic wave (SAW) filters
Data Source
AI summary
The present disclosure relates to a split-band duplexer architecture that takes advantage of a relationship between a frequency division duplex (FDD) transmit band, an FDD receive band, and a time division duplex (TDD) band, which has frequencies located between FDD transmit band frequencies and FDD receive band frequencies. As such, by splitting the FDD receive and transmit bands into two sub-bands, two separate sub-band duplexers may be used to fully support the FDD receive and transmit bands. Further, a passband of one of the sub-band duplexers may be widened to support the TDD band while transmitting, and a passband of the other of the sub-band duplexers may be widened to support the TDD band while receiving. By using sub-band duplexers, isolation margins and insertion loss margins may be increased, which may allow use of standard filter components, such as surface acoustic wave (SAW) filters.