Inductive Coupler Substrate for Transmit-Receive Isolation

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Solution Overview

Problem

Communication devices face signal leakage issues due to congested transmission mediums, which existing filters struggle to effectively address, leading to interference between transmission and reception signals.

Innovation Solution

A substrate with an inductive coupler is introduced, featuring a first inductor coupled to a transmitter filter and antenna, and a second inductor connected to ground, generating an induced signal that counteracts leakage signals traveling through the transmission filter, thereby improving isolation between transmission and reception signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional filters are used to isolate signals in congested transmission medium, then signal filtering capability is provided, but signal leakage occurs between transmission and reception paths

Engineering Contradiction:

Improvesignal leakageVSAvoidisolation between transmission and reception signals

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

An inductive coupler comprising first and second inductors is introduced as an intermediary component between the transmission filter and antenna. The first inductor couples to the transmission filter and antenna, while the second inductor couples to ground and generates an induced signal that counteracts leakage signals, thereby mediating the isolation between transmission and reception paths without requiring direct modification of the filters themselves.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful leakage signal into a beneficial counteracting signal. The second inductor is specifically configured to generate an induced signal that opposes and cancels the leakage signal traveling through the transmission filter, transforming the problematic leakage into a useful cancellation mechanism that enhances isolation between transmission and reception paths.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If additional electromagnetic interference shielding is implemented to reduce signal leakage, then isolation between transmission and reception signals is improved, but device complexity and cost increase

Engineering Contradiction:

Improveisolation between transmission and reception signalsVSAvoidelectromagnetic interference shielding structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/physical approach of electromagnetic shielding with an electrical/inductive approach. Instead of adding physical shielding structures that block electromagnetic fields, the solution uses inductive coupling and signal generation to actively cancel leakage signals, substituting a complex mechanical shielding system with a more integrated electrical circuit solution.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If the number of inductors in the inductive coupler is increased to further reduce signal leakage, then isolation performance is improved, but manufacturing precision requirements and device complexity increase

Engineering Contradiction:

Improvesignal leakage reductionVSAvoidinductor configuration and positioning

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent employs a balanced approach with exactly two inductors in the inductive coupler - neither too few to be ineffective nor too many to create excessive complexity. This partial action approach achieves sufficient signal leakage reduction through the coordinated operation of the first and second inductors, avoiding the manufacturing precision and complexity issues that would arise from using three or more inductors.

Inventive Principle:

Principle #16Partial or excessive action

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 inductive coupler reduces signal leakage by up to 50% and enhances isolation between transmission and reception signals, particularly for out-of-band frequencies, potentially eliminating the need for additional electromagnetic interference shielding.

Implementation Method 1

the second inductor is configured such that the rejected signal traveling through the second inductor causes the first inductor to generate an induced signal that counteracts a leakage signal traveling through the transmission filter

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3949128B1Substrate comprising an inductive coupler for signal leakage reduction

Publication Date: 2024.08.07 QUALCOMM INC

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AI summary

A substrate that includes at least one dielectric layer and an inductive coupler formed in the at least one dielectric layer. The inductive coupler includes a first inductor and a second inductor. The first inductor is formed in the at least one dielectric layer. The first inductor is configured to be coupled to a transmitter filter and an antenna. The second inductor is formed in the at least one dielectric layer. The second inductor is configured to be coupled to the transmitter filter and ground. The second inductor is configured to provide a path to ground for a rejected signal having a rejected frequency. The second inductor is configured such that the rejected signal traveling through the second inductor causes the first inductor to generate an induced signal that counteracts a leakage signal traveling through the transmission filter.