Reconfigurable radio frequency (RF) bandstop / intermediate frequency (IF) bandpass filter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless devices face challenges in non-contiguous carrier aggregation due to spurious desensitization and gain loss, leading to poor noise figure and system performance, particularly in single-LO architectures which lack early filtering in the receive chain.
Innovation Solution
A reconfigurable filter circuit with a transimpedance amplifier and switchable feedback path, allowing for bandpass or low-pass responses based on switch configuration, is introduced to facilitate efficient filtering and reduce jammer impact, preserving gain and noise figure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-LO NCCA architecture is used, then device complexity is reduced, but receive sensitivity deteriorates due to lack of early filtering and gain drop
Solution Approach 1:
The patent applies preliminary action by implementing early filtering in the receive chain before the signal is fully processed. The bandpass filter is positioned to filter signals early in the receive path, preventing spurious desensitization and gain drop before they degrade receive sensitivity. This early intervention resolves the contradiction by maintaining reliability without requiring complex dual-LO architecture.
2Reliability
If early filtering is implemented in receive chain, then receive sensitivity is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a reconfigurable filter that can operate in multiple modes (bandpass and low-pass) depending on the operational requirements. This single multi-functional filter replaces what would otherwise require separate filtering stages for different operating conditions, improving receive sensitivity while avoiding the complexity of multiple dedicated filters or dual-LO architecture.
Solution Approach 2:
The patent applies dynamics by implementing a reconfigurable filter with switchable feedback paths that can dynamically change its transfer function between bandpass and low-pass modes. This dynamic reconfiguration allows the system to adapt to different carrier aggregation scenarios, providing early filtering when needed while maintaining architectural simplicity through a single reconfigurable component rather than multiple fixed filters.
3Object-affected harmful factors
If bandpass filtering is applied early in receive chain, then spurious desensitization is reduced, but filtering complexity increases
Solution Approach 1:
The patent applies feedback by implementing a feedback path with switches that can be configured to provide bandpass filtering through the reconfigurable filter. The feedback mechanism allows the system to control the filter's transfer function dynamically, enabling early bandpass filtering to reduce spurious desensitization while managing complexity through intelligent control rather than complex hardware structures.
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 reconfigurable filter circuit enhances receive sensitivity and linearity by enabling early filtering in the receive chain, effectively mitigating spurious desensitization and improving signal path linearity for non-contiguous carrier aggregation.
Implementation Method 1
The reconfigurable filter circuit has a first path including a transimpedance amplifier (TIA). The transimpedance amplifier has an input that receives an input current and an output that outputs a voltage.
Implementation Method 2
The switchable feedback path includes a first low-pass filter coupled to an output of the TIA. The switchable feedback path also includes a first switch to couple the feedback path to provide a feedback current to the first path resulting in a bandpass response in the output voltage when the switch is closed and a low-pass response in the output voltage when the switch is open.
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
A reconfigurable filter circuit has a first path including a transimpedance amplifier (TIA). The transimpedance amplifier has an input that receives an input current and an output that outputs a voltage. The reconfigurable filter circuit also includes a switchable feedback path. The switchable feedback path includes a first low-pass filter coupled to an output of the TIA. The switchable feedback path also includes a first switch to couple the feedback path to provide a feedback current to the first path resulting in a bandpass response in the output voltage when the switch is closed and a low-pass response in the output voltage when the switch is open.