Selective Notch Filter Bypass Circuit for RF Emissions

Solution Overview

Problem

Radio-frequency devices face performance inefficiencies when implementing intermittent operating characteristics to suppress emissions, such as lower DC current efficiency and higher insertion losses, which are often imposed during nominal operating conditions.

Innovation Solution

The implementation of an emissions-suppression circuit comprising a notch filter, a switch assembly, and a duplexer, which selectively couples the notch filter to a transmit path to attenuate specific frequency components and minimize performance losses during both nominal and intermittent operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a notch filter is continuously coupled to the transmit path to suppress emissions, then emissions suppression performance is improved, but insertion losses increase and DC current efficiency decreases

Engineering Contradiction:

ImproveemissionsVSAvoidinsertion losses

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the notch filter coupling configurable through control signals. The switch assembly dynamically connects or disconnects the notch filter from the transmit path based on operational requirements, allowing the system to transition between emissions suppression mode and normal operation mode, thereby optimizing the trade-off between emissions suppression and insertion losses

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameter of the notch filter from continuous engagement to selective engagement. By controlling the switch assembly to connect or disconnect the notch filter based on operational conditions, the system adjusts the filter's presence in the signal path, reducing insertion losses during normal operation while maintaining emissions suppression capability when needed

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If a notch filter is continuously coupled to the transmit path to suppress emissions, then emissions suppression performance is improved, but DC current efficiency decreases

Engineering Contradiction:

ImproveemissionsVSAvoidDC current efficiency

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the notch filter coupling configurable through control signals. The switch assembly dynamically connects or disconnects the notch filter from the transmit path based on operational requirements, allowing the system to transition between emissions suppression mode and normal operation mode, thereby optimizing the trade-off between emissions suppression and insertion losses

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameter of the notch filter from continuous engagement to selective engagement. By controlling the switch assembly to connect or disconnect the notch filter based on operational conditions, the system adjusts the filter's presence in the signal path, reducing insertion losses during normal operation while maintaining emissions suppression capability when needed

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If a switch assembly is used to selectively couple the notch filter, then operational flexibility is improved, but device complexity increases

Engineering Contradiction:

Improveoperational flexibilityVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the filter control function into separate components: the notch filter, the switch assembly, and the control circuitry. This modular approach allows the notch filter to be independently controlled and coupled or decoupled from the transmit path, providing operational flexibility while keeping each component's complexity manageable

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses the switch assembly as an intermediary component between the notch filter and the transmit path. This intermediary element enables selective coupling and decoupling of the notch filter based on control signals, providing operational flexibility without requiring the notch filter to be permanently integrated into the signal path, thus managing overall device complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively reduces emissions when intermittent operating characteristics are required, while maintaining optimal performance during nominal conditions by minimizing insertion losses and avoiding unnecessary activation of the notch filter.

Implementation Method 1

a notch filter associated with a first frequency range

Methodology Applied

Scientific EffectFrequency-selective filtering: Filter (electronic)

Implementation Method 2

a duplexer coupled to the switch assembly. The transmit path is associated with two or more switch connections in the notch-filter state and is associated with one switch connection in the bypass state

Methodology Applied

Scientific EffectFrequency-dependent isolation: Filter (electronic)

Data Source

PatentUS20250167819A1Selective notch filter bypass

Publication Date: 2025.05.22 SKYWORKS SOLUTIONS INC

AI summary

Architectures and techniques relate to selectively implementing a notch filter to filter emissions. For example, a circuit can include a filter associated with a first frequency range, a first switch, and a second switch. The first switch can be controlled to operate in a filter state to route a signal through the filter and controlled to operate in a bypass state to route the signal to an output node while bypassing the filter. The second switch can be controlled to operate in the filter state to route the signal from the filter to the output node.