Tunable LC Filter Switching for ISM Isolation Without GSM Power Loss

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Solution Overview

Problem

Conventional portable electronic devices face performance issues due to the need for ISM-band filters in certain wireless communication modes, which cause extra power loss in other modes, and existing filtering technologies do not effectively manage these variations.

Innovation Solution

A frequency tunable filter apparatus comprising a controller, an LC resonator, a switching unit, and a resonance adjustment unit, which selectively changes resonance characteristics to enable or disable conduction paths, allowing for efficient filtering control across different wireless communication modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an ISM-band filter is added to prevent 2.4 GHz signal coupling in EDGE mode, then signal isolation performance is improved, but power loss increases in GSM mode

Engineering Contradiction:
Improvesignal isolation performanceVSAvoidpower loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements a dynamically configurable filter system where the filter structure changes based on operating mode. Switching units selectively connect or disconnect filter branches (ISM-band filter, LC resonator) depending on whether the device operates in GSM or EDGE mode, transforming a static filter into a dynamic, adaptive structure that optimizes performance for each mode

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The filter system is designed to perform multiple functions across different operating modes. The same filter architecture serves both GSM mode (where ISM-band filtering is disabled) and EDGE mode (where ISM-band filtering is enabled), allowing a single universal filter structure to replace what would traditionally require separate dedicated filters for each mode

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

2Reliability

If a fixed filter structure is used to ensure filtering performance in EDGE mode, then signal isolation is improved, but adaptability to different communication modes deteriorates

Engineering Contradiction:
Improvesignal isolationVSAvoidadaptability to communication modes
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The filter system transitions from a fixed structure to a dynamic, reconfigurable architecture. Control logic detects the operating mode (GSM or EDGE) and automatically adjusts the filter configuration by activating or deactivating specific filter branches through switching units, enabling the filter to adapt its characteristics to match the requirements of each communication mode

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The filter is divided into separate functional segments or branches (ISM-band filter branch, LC resonator branch) that can be independently controlled. Each segment can be selectively activated or deactivated based on the operating mode, allowing the system to optimize performance for GSM or EDGE mode without compromising the other

Inventive Principle:
Principle #1Segmentation

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

The apparatus minimizes side effects and ensures overall performance by adaptively tuning filtering settings to match specific communication modes, reducing power loss and meeting performance standards.

Implementation Method 1

an LC resonator arranged to resonate at a rejection frequency

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3166224B1Frequency tunable filter with voltage stressed relaxed switch, and associated apparatus
Publication Date: 2019.10.09 MEDIATEK INC
  • EP3166224B1 patent drawingFigure 1
  • EP3166224B1 patent drawingFigure 2~3
  • EP3166224B1 patent drawingFigure 4~5

AI summary

A frequency tunable filter (110) and an associated apparatus (100) are provided, where the frequency tunable filter (110) may include a plurality of ports (IN, OUT) including an input port (IN) and an output port (OUT), and may further include an inductor-capacitor (LC) resonator (110R), a switching unit (110S) that is coupled between the LC resonator (110R) and a ground terminal of the frequency tunable filter (110), and a resonance adjustment unit (110LC, L2, C2) that is coupled between the LC resonator (110R) and the ground terminal. For example, the LC resonator (110R) may include a first terminal coupled to each of the input port (IN) and the output port (OUT), and may further include a second terminal, the switching unit (110S) may selectively provide a conduction path between the second terminal of the LC resonator (110R) and the ground terminal, and the resonance adjustment unit (110LC, L2, C2) may selectively change a resonance characteristic of the LC resonator (110R).