RF Module Signal Path Switching to Prevent Loss and Leakage
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Solution Overview
Problem
Existing radio frequency modules experience signal loss and leakage in low-output modes due to switch operation, which affects transmission efficiency in both high-output and low-output modes.
Innovation Solution
Incorporating a first and second power amplifier, a filter, a switch, and a matching circuit that allows the amplified signals to pass through while the switch disconnects in low-output mode and connects in high-output mode, with the matching circuit configured to appear infinite from the high-output mode perspective to prevent signal leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switch is used to select between high-output mode and low-output mode, then the transmission circuit can operate in different output modes, but signal loss occurs in the low-output mode due to switch insertion loss
Solution Approach 1:
The invention divides the transmission circuit into separate signal paths: a first signal path for high-output mode and a second signal path for low-output mode. By segmenting the circuit architecture, the switch is only placed in the first signal path, so it does not affect signal transmission in the second signal path, thereby eliminating switch-induced signal loss in low-output mode.
Solution Approach 2:
A second switch is introduced as an intermediary component to control signal routing between the two signal paths. This intermediary switch enables seamless switching between high-output and low-output modes without causing signal loss in the low-output path, as it only activates when needed for mode transition.
2Power
If a switch connects the first power amplifier to the filter in high-output mode, then high-power transmission is achieved, but signal leakage from high-output mode into the low-output signal path occurs
Solution Approach 1:
The invention separates the high-output and low-output signal paths into distinct segments. The first power amplifier and its associated switch are confined to the first signal path, while the second signal path remains isolated. This segmentation prevents high-power signals from leaking into the low-output path, as the paths are physically and electrically separated.
Solution Approach 2:
The harmful effect of signal leakage is eliminated by extracting the low-output signal path from the high-output signal path. The second signal path is designed to be independent, with its own dedicated components, so that high-power transmission in the first path does not interfere with or leak into the second path.
3Adaptability or versatility
If two switches are used for mode selection, then high-output and low-output modes can be selected, but device complexity increases
Solution Approach 1:
The first switch is designed to serve multiple functions: it not only selects between high-output and low-output modes but also acts as a leakage prevention mechanism by isolating the first power amplifier from the filter in low-output mode. This multi-functionality reduces the need for additional switches, thereby limiting the increase in device complexity.
Data Source
AI summary
A radio frequency module includes a first power amplifier, a second power amplifier, a filter, a switch, and a matching circuit. The first power amplifier outputs a first amplified signal. The second power amplifier outputs a second amplified signal. The filter allows the first amplified signal and the second amplified signal to pass through. The switch has a first terminal and a second terminal. The first terminal is connected to an output portion of the first power amplifier. The second terminal is connected to the filter. The switch changes over connection and disconnection of the first terminal and the second terminal. The matching circuit is connected between an output portion of the second power amplifier and a signal path between the second terminal of the switch and the filter.