Switching Circuit for Cellular and Wi-Fi Filter Coexistence

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Solution Overview

Problem

Existing wireless communication devices face challenges in efficiently coexisting and separating adjacent frequency bands, such as cellular and Wi-Fi bands, due to high insertion loss and frequency roll-off at band edges, as well as Tx leakage and receive band noise.

Innovation Solution

A switching circuit is introduced that includes multiple filters and switches to concurrently route radio frequency signals from an antenna through specific filter combinations, allowing for the separation of adjacent frequency bands and improving out-of-band attenuation and in-band insertion loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single filter is used for adjacent frequency bands, then device complexity is reduced, but frequency separation performance deteriorates due to high insertion loss and frequency roll-off at band edges

Engineering Contradiction:

Improvefilter configurationVSAvoidfrequency separation performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent divides the second frequency band into two separate regions (first region and second region) and assigns different filters to each region. The first filter handles the first frequency band and the first region of the second band, while the second filter handles the second region of the second band. This segmentation allows each filter to be optimized for its specific frequency range, reducing frequency roll-off and insertion loss at band edges while maintaining manageable device complexity through modular filter design.

Inventive Principle:

Principle #1Segmentation

2Productivity

If frequency bands are placed closer together to reduce spectral occupancy, then productivity is improved, but harmful factors increase due to Tx leakage and receive band noise

Engineering Contradiction:

Improvespectral efficiencyVSAvoidTx leakage and receive band noise

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

By segmenting the second frequency band into two distinct regions with separate filters, the patent creates clearer frequency separation between adjacent bands. This segmentation enables tighter spectral packing (improving productivity) while maintaining adequate isolation between bands, thereby reducing Tx leakage and receive band noise through proper filter placement and region definition.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate frequency regions and corresponding filters between adjacent frequency bands. These intermediate regions act as buffers that reduce direct interference between bands. The intermediate filters provide additional isolation, effectively reducing harmful factors like Tx leakage and receive band noise while allowing bands to be placed closer together for improved spectral efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If multiple filters are used for concurrent routing, then frequency band separation is improved, but device complexity increases

Engineering Contradiction:

Improvefrequency band separationVSAvoidswitching circuit configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The switching circuit is designed with multi-functionality to handle multiple frequency bands and regions concurrently. The same switching infrastructure routes signals for different bands (first frequency band, second frequency band regions) and supports both TDD and FDD modes. This universal design achieves improved frequency band separation through multiple filters while controlling device complexity by reusing switching components across different operational modes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent segments the filtering function into distinct first and second filters, each handling specific frequency regions. This segmentation improves frequency band separation by dedicating specific filters to specific bands. The complexity is managed by organizing these segmented filters within a unified switching circuit architecture that uses standardized switching components for concurrent routing, making the increased complexity manageable and systematic.

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 proposed solution enables improved performance, reduced antenna count, and enhanced coexistence of cellular and Wi-Fi signals by creating larger gaps in frequency offset, reducing in-band insertion loss, and minimizing Rx DeSense or degradation.