Front End Circuit Band Segmentation for Interference Reduction

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Solution Overview

Problem

Existing wireless communication devices face challenges in reducing interference between multiple frequency bands, particularly in LTE systems, where sharing an antenna terminal increases cost and size but worsens band interference, while separate antennas improve isolation but increase costs and complexity.

Innovation Solution

A front-end circuit design that includes separate antenna terminals for different frequency bands, with a separating circuit to manage signal transmission and reception between these terminals, using filters and switches to minimize interference and reduce the number of RF connectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If separate antenna terminals are provided for different frequency bands, then interference between bands is reduced and isolation is improved, but the number of RF connectors increases and cost and size increase

Engineering Contradiction:

Improveinterference between bandsVSAvoidnumber of RF connectors

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent divides the frequency bands into different groups (low band and high band) and provides separate antenna terminals for each group. This segmentation allows signals from different frequency bands to be transmitted and received through dedicated terminals, reducing interference between bands while maintaining a manageable number of connectors.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent makes each antenna terminal capable of handling both transmission and reception functions across multiple frequency bands within its group. For example, the first antenna terminal handles both transmission and reception for low and high bands, reducing the need for separate dedicated terminals for each function and band combination.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Device complexity

If antenna terminals are shared between frequency bands, then cost and size are reduced, but interference between bands increases and isolation deteriorates

Engineering Contradiction:

Improvenumber of RF connectorsVSAvoidinterference between bands

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

Instead of complete sharing or complete separation, the patent segments the frequency bands into groups and provides partial sharing within groups. The first antenna terminal serves both low and high bands for transmission and reception, while the second antenna terminal serves middle band, creating a balanced approach that reduces interference compared to full sharing while avoiding the complexity of full separation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different connection strategies to different frequency bands based on their specific characteristics. Low and high bands share the first antenna terminal, while middle band uses the second antenna terminal. This localized optimization allows each band group to have appropriate isolation while maintaining overall system compactness.

Inventive Principle:

Principle #3Local quality

3Device complexity

If a multiplexer is used to unify antenna terminals, then the number of RF connectors is reduced, but loss increases and interference between bands worsens

Engineering Contradiction:

Improvenumber of RF connectorsVSAvoidsignal loss

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent avoids using a single multiplexer for all frequency bands by segmenting the bands into groups that share common antenna terminals. This segmentation reduces the complexity and loss associated with cascaded multiplexing stages, as each antenna terminal handles a specific group of bands with dedicated filtering.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces band-specific filters as intermediary components between the antenna terminals and the radio frequency circuits. These filters act as mediators that selectively pass desired frequency bands while blocking others, reducing interference and signal loss without requiring complex multiplexing arrangements.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9985681B2Front end circuit, module, and communication device

Publication Date: 2018.05.29 TAIYO YUDEN KK

AI summary

A module comprising: a first transmit filter that passes a transmission signal of a first band; a first receive filter that passes a reception signal of the first band; a second transmit filter that passes a transmission signal of a second band; a second receive filter that passes a reception signal of the second band; a third transmit filter that passes a transmission signal of a third band; and a third receive filter that passes a reception signal of the third band, wherein a transmit band of the first band overlaps with at least a part of a receive band of the second band, a receive band of the third band does not overlap with the transmit band of the first band or a transmit band of the second band, and the third receive filter is located between the first receive filter and the second receive filter.