Isolated Active RF Combiner for Parasitic Neutralization
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Solution Overview
Problem
Existing wireless circuitry with signal combiners face challenges in achieving satisfactory performance levels due to parasitic components that limit isolation and introduce phase errors, particularly in active combiners like common source and common gate combiners.
Innovation Solution
The implementation of an active signal combiner with common source or common gate transistors, coupled with capacitors and resistors in parallel configurations, to compensate for parasitic components and enhance isolation, thereby improving the common mode rejection ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active signal combiner with common source or common gate transistors is used, then signal combining capability is improved, but parasitic components limit isolation and introduce phase errors
Solution Approach 1:
The patent applies neutralization techniques that convert the harmful effect of parasitic capacitances into a beneficial outcome by introducing compensating parasitic elements. The neutralization circuit includes parasitic elements configured to cancel the unwanted effects of transistor parasitic capacitances, thereby improving isolation between signal paths while maintaining the active combining capability. This directly addresses the contradiction by transforming the harmful parasitic effects into a neutral or beneficial state.
Solution Approach 2:
The patent introduces a neutralization circuit as an intermediary element between the transistors and the signal paths. This neutralization circuit includes parasitic elements that act as mediators to cancel the unwanted interactions caused by transistor parasitic capacitances. The intermediary circuit provides the necessary compensation without disrupting the primary signal combining function, thereby resolving the isolation problem while preserving the active combiner benefits.
2Power
If transistors are used in the signal combiner, then active signal combining is achieved, but phase errors are introduced
Solution Approach 1:
The patent applies neutralization techniques that convert the harmful effect of parasitic capacitances into a beneficial outcome by introducing compensating parasitic elements. The neutralization circuit includes parasitic elements configured to cancel the unwanted effects of transistor parasitic capacitances, thereby improving isolation between signal paths while maintaining the active combining capability. This directly addresses the contradiction by transforming the harmful parasitic effects into a neutral or beneficial state.
Solution Approach 2:
The patent employs parameter tuning and optimization in the neutralization circuit to achieve precise phase cancellation. By adjusting the values of parasitic elements and configuring the neutralization circuit parameters, the patent optimizes the cancellation of phase errors introduced by transistor parasitic capacitances. This parameter-based approach allows for fine-tuning the phase accuracy while maintaining active signal combining performance.
3Reliability
If isolation in the signal combiner is enhanced, then signal quality is improved, but device complexity increases
Solution Approach 1:
The patent divides the signal combiner into distinct functional segments: the active combining section with transistors and the separate neutralization section with parasitic elements. This segmentation allows the isolation improvement function to be implemented in a dedicated neutralization circuit rather than complicating the entire combiner structure. The modular approach maintains signal quality while managing device complexity through functional separation.
Solution Approach 2:
The patent introduces a neutralization circuit as an intermediary element between the transistors and the signal paths. This neutralization circuit includes parasitic elements that act as mediators to cancel the unwanted interactions caused by transistor parasitic capacitances. The intermediary circuit provides the necessary compensation without disrupting the primary signal combining function, thereby resolving the isolation problem while preserving the active combiner benefits.
Data Source
AI summary
An electronic device may wireless circuitry with first and second transmission lines. A signal combiner may couple the first and second transmission lines to a path. The combiner may include an output circuit coupled to the path, a first transistor that couples the first transmission line to a first input of the output circuit, and a second transistor that couples the second transmission line to a second input of the output circuit. The signal combiner may include a first capacitor that couples the first transmission line to the second input and may include a second capacitor that couples the second transmission line to the first input. If desired, resistors may be coupled in parallel with the capacitors. The output circuit may exhibit a high common mode rejection ratio. The output circuit, the capacitors, and/or the resistors may neutralize parasitic components of the transistors.