Distributed Amplifier Non-Linearity Cancellation Stage
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Solution Overview
Problem
Distributed amplifiers face challenges in achieving high linearity due to third-order intermodulation distortion (IMD3), which affects their performance in applications such as aerospace and cellular infrastructure.
Innovation Solution
Incorporating a differential non-linearity cancellation stage with a separately controllable bias between the input and output transmission lines, allowing for signal inversion and mitigation of IMD3, thereby enhancing the amplifier's linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If distributed amplifier stages are used to achieve high gain and bandwidth, then the gain-bandwidth product is improved, but third-order intermodulation distortion (IMD3) increases and linearity deteriorates
Solution Approach 1:
The amplifier is segmented into multiple functional stages: distributed amplifier stages for gain and bandwidth, and non-linearity cancellation stages for distortion mitigation. Each stage performs a specific function, allowing the system to achieve high gain-bandwidth product while separately addressing IMD3 through the cancellation stages.
Solution Approach 2:
The non-linearity cancellation stages are designed to produce distortion components that are equal in magnitude but opposite in phase to those generated by the distributed amplifier stages. This preliminary anti-action occurs before the signals combine, causing the harmful IMD3 components to cancel each other out while preserving the desired amplification.
2Object-generated harmful factors
If linearity is improved by adding non-linearity cancellation stages, then IMD3 is mitigated, but device complexity increases
Solution Approach 1:
The non-linearity cancellation stages are merged with the distributed amplifier stages by connecting them between the same input and output transmission lines. This integration allows both functions (amplification and distortion cancellation) to coexist in a unified structure, reducing overall complexity compared to separate cascaded systems.
Solution Approach 2:
The amplifier structure is designed with multi-functionality: the same transmission lines carry both the amplified signal and the cancellation signal, and the bias control circuit performs multiple functions including setting operating points and enabling/disabling cancellation stages. This universality reduces the need for separate dedicated components.
Data Source
AI summary
Distributed amplifiers with controllable linearization are provided herein. In certain embodiments, a distributed amplifier includes a differential input transmission line, a differential output transmission line, and a plurality of differential distributed amplifier stages connected between the differential input transmission line and the differential output transmission line at different points or nodes. The distributed amplifier further includes a differential non-linearity cancellation stage connected between the differential input transmission line and the differential output transmission line and providing signal inversion relative to the differential distributed amplifier stages. The differential non-linearity cancellation stage operates with a separately controllable bias from the differential distributed amplifier stages, thereby providing a mechanism to control the linearity of the distributed amplifier.