RF Power Amplifier Without Matching Network for Multi-Band Efficiency

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Solution Overview

Problem

Current power amplifiers for RF applications face inefficiencies due to the need for impedance transformation networks and band selection switches, leading to increased loss and complexity, especially in multi-band systems.

Innovation Solution

A power amplification system that operates with high-voltage supplies and eliminates impedance transformation circuits and band selection switches by configuring power amplifiers to drive characteristic load impedances of filters directly, allowing for reduced current drain and smaller device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If impedance transformation networks and band selection switches are used in power amplifiers, then the amplifier can operate across multiple frequency bands, but the system complexity and energy loss increase

Engineering Contradiction:

Improvemulti-band operation capabilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the power amplifier system into multiple independent single-band PAs, each optimized for a specific frequency band. Each PA is designed to operate efficiently at a fixed impedance and frequency, eliminating the need for complex impedance transformation networks and band selection switches. The system achieves multi-band capability through parallel independent amplifiers rather than a single reconfigurable amplifier.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a single power amplifier with reconfigurable impedance matching networks to achieve multi-band operation, the patent inverts the approach by using multiple fixed-impedance PAs. Each PA is designed for a specific band with simplified matching, and the system selects which PA to use based on the operating band, thereby reducing overall system complexity.

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If impedance transformation networks are used in power amplifiers, then the amplifier can match different load impedances, but the energy loss increases

Engineering Contradiction:

Improveimpedance matching capabilityVSAvoidenergy loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

Each power amplifier is designed with local optimization for its specific frequency band and impedance requirement. The PAs use fixed impedance values (e.g., 50 Ohms, 75 Ohms, or other characteristic impedances) tailored to their specific band, eliminating the need for broadband impedance transformation networks that would introduce energy loss. The matching network is optimized locally for each PA-band combination rather than using a single lossy broadband solution.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If traditional power amplifiers with impedance transformation circuits are used, then the amplifier can operate at various impedances, but the device size increases

Engineering Contradiction:

Improveimpedance rangeVSAvoiddevice size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent segments the power amplifier function into multiple independent single-band PAs, each with fixed impedance characteristics. This eliminates the need for large broadband impedance transformation networks and variable impedance matching components. Each PA can be miniaturized since it only needs to support a narrow frequency band with fixed impedance, and the overall system size is reduced by eliminating redundant matching network components.

Inventive Principle:

Principle #1Segmentation

4Adaptability or versatility

If band selection switches are used in multi-band power amplification systems, then the system can switch between frequency bands, but the loss and complexity increase

Engineering Contradiction:

Improveband switching capabilityVSAvoidloss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts and eliminates the band selection switch from the signal path by using multiple independent PAs instead of a single PA with switching. Each PA is directly connected to its corresponding band's filter and antenna interface, removing the need for RF switches and associated loss. The band selection function is achieved by activating only the required PA for the current operating band, rather than switching between bands through a common path with switches.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS10084411B2Reduced power amplifier size through elimination of matching network

Publication Date: 2018.09.25 SKYWORKS SOLUTIONS INC

AI summary

Reduced power amplifier size through elimination of matching network. In some embodiments, a power amplification system can include a power amplifier (PA) configured to receive and amplify a radio-frequency (RF) signal. The power amplification system can further include a filter coupled to the PA and configured to condition the amplified RF signal. The PA can be further configured to drive approximately a characteristic load impedance of the filter. Such a configuration of the PA can be achieved by operating the PA with a high-voltage supply. Such a power amplification system can allow elimination of a matching network to, for example, reduce loss and device size.