In-Package Transmission Line Combiner for RF Amplifier Bandwidth
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Solution Overview
Problem
Conventional RF power amplifiers often face a trade-off between efficiency and bandwidth, with many designs achieving high theoretical power efficiency at the cost of lower fractional bandwidth, necessitating the development of amplifiers that can provide both high efficiency and high fractional bandwidth.
Innovation Solution
The implementation of a combiner with a transmission line inside the device package, configured to provide an impedance inverter between the outputs of transistors, facilitates a Doherty amplifier with improved bandwidth and efficiency, utilizing bond wires and intrinsic capacitances to achieve optimal load conditions and phase compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional amplifier designs are used to achieve high theoretical power efficiency, then efficiency is improved, but fractional bandwidth deteriorates
Solution Approach 1:
The patent moves the combiner from an external component to an integrated structure within the package, utilizing the third dimension (vertical integration) to accommodate transmission lines and combining networks that provide both impedance inversion and broadband matching, thereby resolving the efficiency-bandwidth tradeoff through spatial reconfiguration
Solution Approach 2:
The transmission line within the package serves multiple functions simultaneously: it provides impedance inversion, acts as a combiner for multiple amplifier outputs, and enables broadband matching. This multi-functionality allows the amplifier to achieve both high efficiency and wide fractional bandwidth without requiring separate dedicated components
2Adaptability or versatility
If a transmission line combiner is integrated inside the device package, then fractional bandwidth is improved, but device complexity increases
Solution Approach 1:
The patent merges the combiner function with the package structure itself, integrating transmission lines and combining networks directly into the package substrate. This consolidation eliminates the need for separate external combiner components and reduces the overall system complexity despite the enhanced functionality
3Loss of energy
If transmission line length is optimized for impedance inversion, then efficiency is improved, but bandwidth may be limited
Solution Approach 1:
The patent employs adjustable and variable transmission line configurations that can be tuned to provide both the required impedance inversion and broadband matching. The dynamic adjustment of transmission line parameters allows simultaneous optimization for both efficiency and wide fractional bandwidth across different operating conditions
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 approach results in a significant increase in fractional bandwidth, up to 20% or greater, while maintaining high efficiency at both peak and back-off power levels, with reduced size and improved circuit performance compared to conventional amplifiers.
Implementation Method 1
a combiner that includes a transmission line inside the device package, where the transmission line has a length configured to provide an impedance inverter between the outputs of transistors in the amplifier
Implementation Method 2
utilizing bond wires and intrinsic capacitances to achieve optimal load conditions and phase compensation
Data Source
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AI summary
The embodiments described herein include amplifiers that are typically used in radio frequency (RF) applications. The amplifiers described herein use a combiner that is implemented inside the device package. Specifically, the amplifiers can be implemented with a combiner that includes a transmission line inside the device package, where the transmission line has a length between first and second ends configured to provide an impedance inverter between the outputs (e.g., drain terminals) of transistors in the amplifier.