Multi-Band RF Output Matching Circuit With Low Switch Loss
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Solution Overview
Problem
In power amplifier circuits, transmitting radio frequency signals across multiple bands results in increased transmission loss due to the on-resistance of switches in the signal path.
Innovation Solution
A radio frequency circuit design incorporating multiple amplification elements, transformers, and filters, with specific circuit configurations that eliminate the need for switches in series paths, using capacitors and inductors in parallel connections to manage signal transmission across different bands with low loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switches are disposed on the signal path to enable multi-band transmission, then adaptability for different bands is improved, but transmission loss increases due to on-resistance
Solution Approach 1:
The patent removes switches from the signal path entirely, extracting the problematic element that caused transmission loss. Instead of using switches to select different filter configurations, the invention employs fixed filter circuits with different bandwidths that can be selectively activated through feedback control, thereby eliminating on-resistance losses while maintaining multi-band adaptability.
Solution Approach 2:
The patent introduces feedback circuits as intermediaries to control the filter bandwidth dynamically. The feedback signal from the output side adjusts the bandwidth of the filter circuit without requiring switches in the main signal path. This intermediary control mechanism enables band switching while avoiding the transmission loss associated with direct switch insertion.
2Adaptability or versatility
If multiple filters with different bandwidths are used for multi-band signals, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple filter functions into a single filter circuit that can dynamically adjust its bandwidth. Instead of using separate filters for different bands, the invention combines them into one adaptive filter whose characteristics are modified by feedback control, thereby reducing the number of discrete components and simplifying the overall circuit structure.
Solution Approach 2:
The patent transforms a static filter configuration into a dynamic one where the filter bandwidth can be adjusted in real-time based on the input signal characteristics. The feedback circuit continuously monitors the output and adjusts the filter parameters accordingly, enabling the same circuit to handle multiple bands without requiring multiple fixed filters.
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
Enables efficient transmission of radio frequency signals across multiple bands with reduced loss, improving signal integrity and reducing the size of the communication device.
Implementation Method 1
a transformer having an input side coil and an output side coil
Implementation Method 2
The first circuit has a first capacitor disposed in series with a first path connecting the one end of the output side coil and the first filter
Data Source
AI summary
A radio frequency circuit includes power amplifiers, a transformer, a filter having a band A as a pass band, a filter having a band B as a pass band, a filter having a band C as a pass band, matching circuits connected to one end of an output side coil, and matching circuits connected to the other end of the output side coil. The matching circuit includes a capacitor disposed at a first path, a switch connected to the first path and a ground, a switch and an inductor connected in series, and the matching circuit includes a capacitor disposed at a second path, and a switch and an inductor connected in series, and the matching circuit includes a switch connected to a third path and the ground.