RF Power Amplifier With Selectable Impedance Matching Across Bands
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Solution Overview
Problem
Conventional RF power amplifiers struggle to provide high linearity across multiple non-overlapping RF frequency bands, requiring multiple amplifiers and increasing complexity and cost in wireless devices, while existing broadband amplifiers are cumbersome and unsuitable for mobile applications.
Innovation Solution
A radio frequency (RF) amplifier circuit with adjustable impedance matching circuits and a multi-band filter that uses a control signal to select and switch between narrow-band filters, enabling frequency-selectable impedance matching and broadening the bandwidth for linear RF power amplification across multiple bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple power amplifiers are used to cover different RF frequency bands, then the frequency band coverage is improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent implements a single power amplifier that can operate across multiple non-overlapping RF frequency bands by incorporating frequency-selectable impedance matching circuits. The amplifier is designed with broadband capabilities and adjustable impedance matching networks that can be tuned to different frequency bands, allowing one amplifier to replace multiple band-specific amplifiers. This multi-functional design enables the amplifier to serve universal purposes across different frequency ranges while maintaining linear amplification performance.
Solution Approach 2:
The patent employs dynamically adjustable impedance matching circuits that can change their impedance characteristics based on the operating frequency band. The impedance matching networks include variable components such as switches, capacitors, and inductors that can be reconfigured through control signals to optimize matching for different frequency bands. This dynamic adaptation allows the single amplifier to maintain optimal performance across multiple frequency bands without requiring separate fixed-tuned amplifiers for each band.
2Reliability
If conventional power amplifiers are designed for a single RF band, then the amplification linearity is maintained, but the bandwidth is limited to 5% or narrower than the center frequency
Solution Approach 1:
The patent employs dynamically adjustable impedance matching circuits that can change their impedance characteristics based on the operating frequency band. The impedance matching networks include variable components such as switches, capacitors, and inductors that can be reconfigured through control signals to optimize matching for different frequency bands. This dynamic adaptation allows the single amplifier to maintain optimal performance across multiple frequency bands without requiring separate fixed-tuned amplifiers for each band.
Solution Approach 2:
The patent changes the impedance parameters of the matching circuits to extend the amplifier's operational bandwidth. By adjusting the impedance matching networks with control signals, the amplifier can adapt its input and output impedance characteristics to match different frequency bands, thereby expanding the usable bandwidth from the conventional 5% limit to cover multiple non-overlapping RF bands while preserving linearity through proper impedance matching at each frequency.
3Adaptability or versatility
If broadband amplifiers are used to cover multiple frequency bands, then the bandwidth is improved, but the device size and complexity become cumbersome and unsuitable for mobile applications
Solution Approach 1:
The patent segments the frequency band coverage function into selectable narrow-band filters that can be individually activated. Instead of using a single large broadband amplifier that covers all frequencies simultaneously, the system divides the frequency range into multiple narrow bands and uses switches to select which band is currently active. This segmentation allows the amplifier to maintain a compact size while achieving broadband coverage through time-multiplexed operation across different frequency segments.
Solution Approach 2:
The patent employs dynamically adjustable impedance matching circuits that can change their impedance characteristics based on the operating frequency band. The impedance matching networks include variable components such as switches, capacitors, and inductors that can be reconfigured through control signals to optimize matching for different frequency bands. This dynamic adaptation allows the single amplifier to maintain optimal performance across multiple frequency bands without requiring separate fixed-tuned amplifiers for each band.
Data Source
AI summary
A radio frequency (RF) amplifier circuit includes a first impedance matching circuit configured to receive an input RF signal, a control circuit configured to produce a band control signal according to the frequency of the input RF signal, an RF amplifier having its input connected to the first impedance matching circuit. The RF amplifier can produce an amplified RF signal in response to the input RF signal. A second impedance matching circuit can receive the amplified RF signal from the RF amplifier. At least one of the first impedance matching circuit and the second impedance matching circuit has an impedance that is adjustable by the band control signal. A multi-band filter can switch the amplified RF signal from the second impedance matching circuit to one of selectable narrow-band filters in response to the band control signal.