Parallel Tx/Rx Impedance Matching Using RX Mutual Inductance

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Solution Overview

Problem

Existing RF front ends face challenges in concurrent impedance matching for transmitter and receiver in TDD communication schemes, leading to issues such as reduced power levels in transmit mode and increased insertion loss in receive mode due to switching device resistance and self-resonant frequencies.

Innovation Solution

The implementation of a parallel-type transmitter/receiver (Tx/Rx) concurrent impedance matching using Rx mutual inductance matching, which involves a transformer with a first and second winding, and a capacitor coupled in series with the first winding, to route RF signals effectively between the antenna, transmitter, and receiver, thereby optimizing impedance matching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If switching devices are used to isolate transmitter and receiver, then isolation between Tx and Rx is improved, but insertion loss increases due to switching device resistance

Engineering Contradiction:

Improveisolation between transmitter and receiverVSAvoidinsertion loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes switching devices from the RF signal path and extracts their isolation function by using the transmitter's own output impedance matching circuit to present a high impedance to the receiver during transmit mode, thereby eliminating insertion loss while maintaining isolation

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The transmitter output impedance matching circuit serves dual functions: matching transmitter output impedance to the antenna and simultaneously providing isolation to the receiver during transmit mode by presenting a high impedance, eliminating the need for separate switching devices

Inventive Principle:

Principle #25Self-service

2Power

If impedance matching circuits are optimized for transmit mode, then transmitter power output is improved, but receiver sensitivity deteriorates due to self-resonant frequencies

Engineering Contradiction:

Improvetransmitter power outputVSAvoidreceiver sensitivity

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent implements dynamic impedance matching by adjusting the receiver input matching circuit based on operational mode (transmit or receive), allowing optimization for each mode separately without compromise, thereby maintaining both transmitter power output and receiver sensitivity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent divides the impedance matching function into separate transmitter output matching circuit and receiver input matching circuit, each independently optimized for their respective functions and modes of operation

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If switching devices are used to change operational modes, then mode switching capability is improved, but device complexity increases

Engineering Contradiction:

Improvemode switching capabilityVSAvoidnumber of switching devices

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the transmitter output impedance matching circuit multi-functional by enabling it to serve both as an impedance matching circuit during transmit mode and as an isolation circuit during receive mode, eliminating the need for separate switching devices

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent removes switching devices from the system entirely and extracts their isolation function through the inherent high impedance presentation of the transmitter output matching circuit during transmit mode

Inventive Principle:

Principle #2Taking out (Extraction)

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

This solution enables efficient impedance matching between the antenna and the transmitter/receiver, reducing signal loss and leakage, and improving the overall performance of the RF front end by maintaining high impedance isolation between transmit and receive modes.

Implementation Method 1

a transformer including a first winding and a second winding; and a capacitor coupled in series with the first winding between a first end of the inductive element and a gate of the first FET, wherein the second winding is coupled to a second end of the inductive element

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

routing a second portion of the received RF signal from the port via an inductive element and a second winding of the transformer, wherein the second portion of the received RF signal increases a mutual inductance of the transformer

Methodology Applied

Scientific EffectMutual inductance: Electromagnetic Induction

Data Source

PatentUS20250080077A1Parallel-type TX/RX concurrent impedance matching utilizing RX mutual inductance matching

Publication Date: 2025.03.06 QUALCOMM INC

AI summary

An apparatus including: a transmitter output impedance matching circuit including an inductive element; a low noise amplifier (LNA) including a first field effect transistor (PET); a receiver input impedance matching circuit, including: a transformer including a first winding and a second winding; and a capacitor coupled in series with the first winding between a first end of the inductive element and a gate of the first FET, wherein the second winding is coupled to a second end of the inductive element; and a radio frequency (RF) port coupled between the first end of the inductive element and the capacitor.