RF Transceiver Dual Transmit Paths for Low-Loss Power Switching

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Solution Overview

Problem

Existing RF transceivers face inefficiencies in power output range from +15 dBm to +30 dBm, especially at lower powers around 0 dBm, and large backoffs, with switches in series with power amplifiers leading to wear, power dissipation, and coupling between paths.

Innovation Solution

A RF transceiver design with separate high and low power transmit paths, using switches and capacitors to isolate paths, eliminating series switches, and incorporating non-linear class power amplifiers and backgate control for improved efficiency and reduced coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a switch is placed in series with the power amplifier output to enable path switching, then path isolation is achieved, but the switch is subjected to high voltage and current stresses leading to wear and potential damage

Engineering Contradiction:

Improvepath switching capabilityVSAvoidswitch durability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts the switch from the series path with the power amplifier output and relocates it to a different position in the circuit where it does not directly handle the high voltage and current swings from the power amplifier, thereby maintaining path switching capability while improving switch reliability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary component or circuit configuration between the power amplifier output and the switch, which mediates the high power signals and protects the switch from direct exposure to voltage and current stresses

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a switch is placed in series with the power amplifier output for path switching, then transmit/receive mode switching is enabled, but the switch introduces ohmic resistance that dissipates power and reduces efficiency

Engineering Contradiction:

Improvetransmit receive mode switchingVSAvoidpower dissipation

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The switch is extracted from the series path and repositioned in a configuration where it does not introduce ohmic resistance into the main signal path during transmission, thereby enabling mode switching while minimizing power dissipation

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of placing the switch in series with the power amplifier output, the patent inverts the approach by using a parallel switch configuration or switching the ground connection, which eliminates the ohmic resistance issue while maintaining switching functionality

Inventive Principle:

Principle #13The other way round (Inversion)

3Device complexity

If a single high power amplifier is used for all transmit modes, then device complexity is reduced, but efficiency deteriorates for lower output powers around 0 dBm

Engineering Contradiction:

Improveamplifier configurationVSAvoidpower amplifier efficiency

Core Design Contradiction:

Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent segments the power amplifier function into multiple independent amplifiers (high power amplifier and low power amplifier), each optimized for specific power ranges, thereby improving overall efficiency while maintaining manageable device complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different characteristics to different amplifiers - the high power amplifier is optimized for high output power operation while the low power amplifier is optimized for lower output power operation, ensuring each operates at peak efficiency in its designated range

Inventive Principle:

Principle #3Local quality

4Adaptability or versatility

If the low noise amplifier input is not directly grounded for protection, then receive path isolation is improved, but the low noise amplifier is exposed to stress from power amplifier signals

Engineering Contradiction:

Improvereceive path isolationVSAvoidlow noise amplifier protection

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an intermediary component between the low noise amplifier input and the antenna, such as a switch or isolation element, which provides protection from power amplifier signals while maintaining proper receive path isolation and signal reception capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12489474B2RF transceiver

Publication Date: 2025.12.02 CSEM CENTRE SUISSE D ELECTRONIQUE ET DE MICROTECHNIQUE SA

AI summary

An RF transceiver (100) which has a single RF antenna port (20) for a receive path, and two transmit paths, a balun (10) including a primary winding (11) and a secondary winding (12), the latter coupled to the RF antenna port (20), the receive path including a low noise amplifier (LNA), the first transmit path including a high power amplifier (HPA), switches (S1, S2), and capacitors (C1, C2), the second transmit path including a low power amplifier (LPA) and a switch (S3).