Tunable Filter Architecture for Wideband Tuning and Deep Rejection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The increasing demand for multi-band support in wireless communication devices leads to a higher number of filters required, resulting in size and cost concerns due to the need for large filter banks with limited adjustable range and low Q values.

Innovation Solution

A tunable filter design incorporating a tunable bandpass filter and multiple switched fixed-frequency filters, such as Lame-mode resonators, to provide out-of-band rejection with a wide tuning range and high rejection at specific frequencies, reducing the number of components and area requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple fixed-frequency filters are used to support multiple bands, then frequency band coverage is improved, but device size and cost increase

Engineering Contradiction:

Improvefrequency band coverageVSAvoiddevice size

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent combines multiple fixed-frequency filters with a single tunable bandpass filter into one integrated filter unit. The fixed-frequency filters handle specific frequency bands while the tunable filter adjusts to different bands, merging the functions of multiple separate filters into a unified structure that reduces overall device size.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The tunable bandpass filter serves multiple functions by being able to tune across different frequency bands, replacing what would traditionally require multiple separate fixed-frequency filters. This multi-functional approach allows the same filter component to adapt to various frequency requirements, reducing the total number of components needed.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple fixed-frequency filters are used to support multiple bands, then frequency band coverage is improved, but manufacturing cost increases

Engineering Contradiction:

Improvefrequency band coverageVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple filter functions into a single integrated unit combining fixed-frequency filters and a tunable bandpass filter. This consolidation reduces the total component count and simplifies the manufacturing process, thereby lowering production costs while maintaining multi-band support capabilities.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The tunable bandpass filter utilizes variable capacitance (through MEMS or varactor diodes) to change its resonant frequency parameter dynamically. This parameter adjustment capability allows a single filter to replace multiple fixed-frequency filters, reducing manufacturing complexity and cost.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If a tunable bandpass filter is used, then tuning range is improved, but out-of-band rejection performance deteriorates

Engineering Contradiction:

Improvetuning rangeVSAvoidout-of-band rejection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent merges fixed-frequency filters with the tunable bandpass filter in a hybrid configuration. The fixed-frequency filters provide strong out-of-band rejection at their specific frequencies, while the tunable filter provides broad tuning capability. Together, they compensate for each other's weaknesses, achieving both wide tuning range and high rejection performance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The filter system is segmented into two functional parts: fixed-frequency filters that handle specific frequency bands with high rejection, and a tunable bandpass filter that provides broad coverage. This segmentation allows each component to excel at its designated function, with the fixed filters providing sharp rejection and the tunable filter providing flexibility.

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 solution achieves a smaller size and lower cost by enabling deep rejection across multiple frequency bands with a wide tuning range, even with low-Q bandpass filters, addressing the size and cost issues of traditional filter banks.

Implementation Method 1

fixed frequency filters, each of a different corresponding fixed frequency, connected in parallel between ground and a line connecting the tunable bandpass filter to the input port and/or the output port and configured to provide high rejection at the corresponding fixed frequency

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

the tunable bandpass filter includes a MEMS (Micro-Electro-Mechanical System) based capacitor

Methodology Applied

Scientific EffectMEMS (Micro-Electro-Mechanical System): Microelectromechanical Systems

Data Source

PatentUS11923830B2Tunable filter

Publication Date: 2024.03.05 HUAWEI TECH CO LTD

AI summary

A tunable filter with wide tuning range and high out-of-band rejection is achieved with a tunable bandpass filter and a number of cascaded, fixed frequency Lame-Mode Resonators (LMRs) notch filters or other resonators. In some embodiments, the filter can be implemented with all of the elements on an integrated circuit, saving space for use in applications such as mobile phones or other mobile communication devices.