RF Amplifier Bypass Resonance for Low-Loss Linearity

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Solution Overview

Problem

Wireless communication amplifiers face challenges in achieving optimal performance in both gain modes and bypass modes due to loading and linearity issues, where optimizing one mode negatively affects the other, and the size of switches and passive components limit performance.

Innovation Solution

The implementation of a variable-gain signal amplifier with a resonant structure that provides a substantially open impedance in bypass mode, isolating the amplifier core from the bypass circuit, allowing independent optimization of both components to enhance performance in gain modes and bypass modes, and incorporating a bypass circuit with a resonant structure switch, capacitor, and inductor to create a low-loss bypass path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the amplifier core and bypass circuit are coupled together to allow signal routing between gain modes and bypass mode, then the amplifier can provide multiple operating modes, but the loading effect between the amplifier core and bypass circuit degrades performance in both modes

Engineering Contradiction:

Improvemultiple operating modesVSAvoidloss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

A resonant structure is introduced as an intermediary component between the amplifier core and bypass circuit. This resonant structure provides frequency-selective coupling that isolates the amplifier core from loading effects in bypass mode while enabling proper signal routing in gain modes, thereby reducing loss without sacrificing mode versatility

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The resonant structure's impedance characteristics are changed with frequency to achieve mode-dependent isolation. At bypass mode frequencies, the resonant structure presents high impedance to block loading effects, while at gain mode frequencies, it allows proper coupling, thus dynamically adjusting parameters based on operating conditions

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the amplifier core is optimized for high gain performance, then gain modes achieve optimal performance, but the bypass mode performance is degraded due to loading effects

Engineering Contradiction:

Improvegain mode performanceVSAvoidloss in bypass mode

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The resonant structure acts as a frequency-selective intermediary that protects the optimized amplifier core from bypass circuit loading. By presenting high impedance at bypass frequencies, it allows the amplifier core to be optimized for gain modes without compromising bypass mode performance

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If the bypass circuit is optimized for low loss, then bypass mode performance improves, but the amplifier core performance in gain modes is degraded due to interaction effects

Engineering Contradiction:

Improveloss in bypass modeVSAvoidgain mode performance

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The resonant structure provides frequency-selective isolation that prevents bypass circuit optimization from interfering with amplifier core performance. By blocking interaction at different frequencies, it allows independent optimization of both the bypass circuit for low loss and the amplifier core for gain mode reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If switches and passive components are made larger to improve performance, then reliability improves, but device complexity and size increase

Engineering Contradiction:

ImproveperformanceVSAvoidsize of switches and passive components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The resonant structure exploits frequency-dependent impedance changes to achieve isolation without requiring large component sizes. By utilizing the natural resonant behavior of LC circuits, it provides high impedance isolation at specific frequencies without needing oversized components, thus maintaining reliability while controlling device complexity

Inventive Principle:

Principle #35Parameter changes

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 solution improves loss by 2 dB to several dB and enhances linearity in bypass modes by decoupling the amplifier core and bypass circuit, enabling tailored performance characteristics across different frequency ranges without affecting high gain modes.

Implementation Method 1

a resonant structure configured to provide a substantially open impedance in the bypass mode

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS10536121B2Amplifier architectures with bypass circuits and resonant structures

Publication Date: 2020.01.14 SKYWORKS SOLUTIONS INC

AI summary

The disclosed technology is related to a radio-frequency (RF) amplifier having a bypass circuit and a resonant structure to improve performance in a bypass mode (e.g., a low gain mode). The disclosed amplifiers have a resonant structure that effectively isolates an amplifier core from a bypass circuit. For example, in a bypass mode, the resonant structure is configured to create an open impedance looking into the amplifier core input. This effectively removes any loading from the amplifier core to the bypass circuit. The disclosed amplifiers with resonant structures improve linearity performance in bypass modes due at least in part to the open impedance to the amplifier core provided by the resonant structure.