Magnetically Coupled Tx/Rx Switch for Shared Antenna Pin Isolation

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Solution Overview

Problem

Existing signal transmission and reception apparatuses face challenges in efficiently managing interference and power efficiency due to cross-coupling effects between transmission and reception paths, leading to potential damage to sensitive components and reduced performance.

Innovation Solution

An apparatus with a transmit/receive switch configuration that uses magnetic coupling of inductors and transistors to control impedance, allowing separate operation in transmit and receive modes, and incorporating a receiver amplifier arrangement with PMOS and NMOS transistors to cancel noise and improve signal integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single pin is used for both transmission and reception, then pin utilization is improved, but interference between transmit and receive paths increases

Engineering Contradiction:
Improvepin utilizationVSAvoidinterference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the transmission and reception paths by introducing separate inductor networks for each function. The first inductor network is dedicated to transmission while the second inductor network is dedicated to reception, allowing both functions to share the same pin without direct interference. This segmentation enables independent optimization of each path while maintaining pin versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces inductor networks as intermediary elements between the shared pin and the transmit/receive circuits. These inductors act as mediators that enable the shared pin to interface with both transmission and reception paths while preventing harmful interactions. The inductors provide galvanic isolation and impedance transformation to minimize cross-coupling effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If transmit and receive paths are closely coupled, then device complexity is reduced, but cross-coupling effects increase causing potential damage to sensitive components

Engineering Contradiction:
Improvecircuit structureVSAvoidcomponent protection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by giving different characteristics to different parts of the circuit. The first inductor network has parameters optimized for transmission while the second inductor network has parameters optimized for reception. This local differentiation allows the circuit to maintain low complexity overall while providing localized protection against cross-coupling effects that could damage sensitive receive components.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements beforehand cushioning by designing the inductor networks with specific impedance characteristics that preemptively reduce cross-coupling effects before they can reach and damage sensitive receive components. The inductors are configured to absorb or reflect potential harmful signals before they can cause damage, protecting the receiver while maintaining circuit simplicity.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If impedance control is implemented to reduce interference, then signal integrity is improved, but power consumption increases

Engineering Contradiction:
Improvesignal integrityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent employs parameter changes by configuring the inductor networks with specific impedance values that optimize signal integrity while minimizing power consumption. The inductors are designed with precise L-values that provide the necessary impedance transformation and isolation without requiring additional active components that would consume power. This passive impedance control achieves signal integrity without the power penalty of active impedance matching circuits.

Inventive Principle:
Principle #35Parameter changes

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 effectively reduces interference, protects sensitive components, enhances power efficiency, and improves signal quality by minimizing cross-coupling effects and maintaining signal-to-noise ratio during transmission and reception.

Implementation Method 1

the first inductor is configured to magnetically couple with the first antenna inductor and the second inductor is configured to magnetically couple with the second antenna inductor for transmission of signalling received at the first set of differential input-output pins from the antenna

Methodology Applied
Scientific EffectMagnetic coupling: Electromagnetic Induction

Data Source

PatentEP4704349A1Apparatus for transmitting and receiving signals
Publication Date: 2026.03.04 NXP BV
  • EP4704349A1 patent drawingFigure 1
  • EP4704349A1 patent drawingFigure 2
  • EP4704349A1 patent drawingFigure 3~4

AI summary

An apparatus comprising: an antenna pin coupled to a pair of antenna inductors; a first set of differential input-output pins coupled to a first pair of inductors. The first pair of inductors are configured to magnetically couple with the pair of antenna inductors for transmitting signalling. The apparatus further comprises a function switch, comprising: a second set of differential input-output pins, coupled to a second pair of inductors. The function switch comprises a first switch between the second pair of inductors. The second pair of inductors are configured to magnetically couple with the pair of antenna inductors for receiving signalling. The function switch comprises a third set of differential input-output pins coupled to a third pair of inductors. The function switch comprises a second switch between the third pair of inductors. The third pair of inductors are configured to magnetically couple with the pair of antenna inductors for receiving signalling.