Reconfigurable RF Multiplexer Filters for Multi-Band Size Reduction

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Solution Overview

Problem

Wireless communication devices supporting multiple frequency bands require a large number of RF filters and additional support circuitry, leading to increased device size and cost.

Innovation Solution

Implementing reconfigurable RF filters using series and shunt resonators with switchable impedances to adjust pass bands, reducing the number of filters needed by dynamically adapting to different frequency standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple separate RF filters are used to support multiple frequency bands, then the device can comply with various standards, but the device size increases

Engineering Contradiction:
Improvecompliance with various standardsVSAvoiddevice size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent implements a single filter structure that can operate across multiple frequency bands by dynamically reconfiguring its resonant characteristics. The filter serves multiple functions (supporting different LTE and Wi-Fi standards) through electronic control of resonator parameters, eliminating the need for separate dedicated filters for each frequency band.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The filter employs dynamic reconfiguration capabilities where resonator parameters (such as capacitance or inductance) can be adjusted in real-time to change the filter's passband characteristics. This dynamic adaptation allows the same physical filter to support different frequency bands as needed, reducing the total number of filters required in the device.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiple separate RF filters are used to support multiple frequency bands, then the device can comply with various standards, but the device cost increases

Engineering Contradiction:
Improvecompliance with various standardsVSAvoiddevice cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent implements a single filter structure that can operate across multiple frequency bands by dynamically reconfiguring its resonant characteristics. The filter serves multiple functions (supporting different LTE and Wi-Fi standards) through electronic control of resonator parameters, eliminating the need for separate dedicated filters for each frequency band.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines multiple filter functions into a single integrated filter structure. By merging the functionality of what would traditionally require multiple separate filters into one reconfigurable unit, the device reduces component count, assembly complexity, and overall manufacturing cost while maintaining multi-band support capabilities.

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If the filter structure is simplified to reduce device size, then fewer filters are needed, but the ability to separate and route signals across frequency bands may be compromised

Engineering Contradiction:
Improvedevice sizeVSAvoidsignal separation and routing
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The filter employs dynamic reconfiguration capabilities where resonator parameters (such as capacitance or inductance) can be adjusted in real-time to change the filter's passband characteristics. This dynamic adaptation allows the same physical filter to support different frequency bands as needed, reducing the total number of filters required in the device.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical parameters of the resonators (such as resonant frequency, quality factor, or impedance) to adapt the filter's frequency response characteristics. By adjusting these parameters, the filter can selectively pass or block different frequency bands, maintaining effective signal separation and routing functionality despite using fewer physical filter components.

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

Reduces the number of filters required, minimizing device size and cost while maintaining effective signal separation and routing across various frequency bands.

Implementation Method 1

first resonators coupled in series between an input and an output, a second resonator coupled as a shunt between a node in the series and a reference voltage

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4708689A1Reconfigurable filters in a multiplexer
Publication Date: 2026.03.11 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP4708689A1 patent drawingFigure 1A~1B
  • EP4708689A1 patent drawingFigure 2
  • EP4708689A1 patent drawingFigure 3A~3B

AI summary

An example filter for radio frequency signals in a radio includes first resonators (2021, 2022, 2023, 2024) coupled in series between an input (IN) and an output (OUT); a second resonator (2041, 2042, 2043, 2044) coupled as a shunt between a node in the series and a reference voltage; and a first circuit coupled in parallel with one of the first resonators or coupled in series with one of the second resonators, the first circuit including a switch (210, 404) coupled in series with an impedance (210, 410).