Broadband LNA Filter Bypass for Carrier Aggregation Receivers
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Solution Overview
Problem
Receiver front ends face challenges in carrier-aggregation modes due to interference from neighboring frequency bands, requiring efficient signal filtering and amplification while minimizing noise and power consumption.
Innovation Solution
A receiver front end with a bandpass filter bypass and a switch matrix that allows carrier-aggregated RF signals to bypass bandpass filters during non-interference conditions, using a broadband low-noise amplifier and matching network to amplify and split signals across multiple frequency bands, reducing noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If bandpass filter is used to exclude signals from neighboring frequency bands, then interference from neighboring bands is reduced, but insertion loss and noise figure increase
Solution Approach 1:
The patent implements a dynamic switching mechanism that alternates between filter bypass mode and filter inclusion mode based on signal conditions. The switch matrix dynamically reconfigures the RF signal path to bypass the bandpass filter when operating in carrier aggregation mode with non-adjacent bands, and engages the filter when neighboring band interference is detected, thereby adapting the filtering state to operational requirements.
Solution Approach 2:
The system changes the operational parameters of the RF signal path by switching between different configurations: in carrier aggregation mode, the signal path parameter is changed to bypass the filter (reducing insertion loss), while in traditional modes, the filter is engaged (maintaining interference rejection). This parameter switching allows optimization of both signal quality and energy efficiency based on operational context.
2Object-affected harmful factors
If bandpass filter is used to exclude signals from neighboring frequency bands, then interference from neighboring bands is reduced, but noise figure increases
Solution Approach 1:
The dynamic switching mechanism allows the receiver to adaptively change its filtering state. When operating in carrier aggregation mode with non-adjacent frequency bands, the system dynamically switches to bypass mode, eliminating the noise figure degradation caused by the filter while maintaining interference rejection through frequency-selective signal processing in the digital domain.
Solution Approach 2:
The switch matrix acts as an intermediary element that controls the signal path configuration. It mediates between the need for interference rejection (filter engagement) and the need for low noise figure (filter bypass), selecting the appropriate path based on operational mode to optimize overall receiver performance.
3Loss of energy
If filter bypass path is used to reduce insertion loss and noise, then signal-to-noise ratio improves, but interference from neighboring bands increases
Solution Approach 1:
The system changes the operational mode parameter to enable filter bypass during carrier aggregation operations with non-adjacent bands, accepting reduced filtering in exchange for improved signal-to-noise ratio. The parameter switching allows the system to operate in bypass mode when the signal structure (carrier aggregation) provides inherent interference protection.
Solution Approach 2:
The patent converts the potential harm of unfiltered signals into a benefit by utilizing the structured nature of carrier aggregation signals. The wideband nature of carrier aggregation allows the system to accept more total signal power (including potential interference) while the digital signal processing can selectively extract the desired aggregated carriers, turning the lack of analog filtering into an opportunity for more flexible signal processing.
4Use of energy by moving object
If switch matrix is configured to bypass bandpass filter, then power consumption is reduced, but signal filtering capability is reduced
Solution Approach 1:
The switch matrix dynamically reconfigures the signal path to bypass the bandpass filter during carrier aggregation mode, eliminating the power consumption associated with filter operation while maintaining adequate interference rejection through the frequency-selective properties of the carrier aggregation signal structure and subsequent digital processing.
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 configuration enhances signal-to-noise ratio and reduces power consumption by avoiding bandpass filter insertion loss and noise, while maintaining high fidelity and noise figure during carrier-aggregation operations.
Implementation Method 1
a low-noise amplifier configured to amplify an input RF signal into an amplified RF signal
Implementation Method 2
a bandpass filter configured to filter a received radio-frequency (RF) signal to provide a filtered RF signal within a first frequency band
Implementation Method 3
a matching network coupled to an amplifier output node for the low-noise amplifier, the matching network being configured to select for the first frequency band to drive a matching network first output node
Implementation Method 4
a switch matrix having a first configuration in which the input RF signal is the filtered RF signal and having a second configuration in which the input RF signal is the bypassed RF signal
Data Source
AI summary
A receiver front end is provided with a bypass mode of operation in which a received carrier-aggregated RF signal bypasses a bandpass filter to drive a broadband low-noise amplifier. The low-noise amplifier amplifies the carrier-aggregated RF signal to form an amplified RF signal.