GaN Amplifier Input Resonance Network for Wideband Harmonic Termination

Solution Overview

Problem

The existing methods for terminating harmonics at the input of Gallium Nitride field-effect transistors (GaN-FETs) are not satisfactory in terms of bandwidth, leading to suboptimal performance in amplification systems.

Innovation Solution

The proposed solution involves an amplifier configuration that includes at least one resonance network between the input terminal and ground, comprising a first inductor, a first capacitor, and a series network with a second inductor and a second capacitor. This configuration presents a susceptance that cancels the input susceptance of the transistor and creates an RF short at the second harmonic frequency within the operational frequency band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a double low-pass matching network is used to terminate harmonics at the gate of GaN-FET, then harmonic termination is achieved, but the bandwidth is limited and not satisfactory

Engineering Contradiction:

Improveharmonic terminationVSAvoidbandwidth

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The matching network is divided into two separate functions: a first matching network (30) dedicated to fundamental frequency impedance matching, and a second matching network (40) dedicated to second harmonic termination. This segmentation allows each network to be independently optimized for its specific frequency range, enabling the first network to provide broad bandwidth matching while the second network provides effective harmonic termination without compromising the overall bandwidth.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A series inductor (Ls) is introduced as an intermediary element between the two matching networks. This inductor acts as a frequency-selective element that isolates the second harmonic termination function from the fundamental frequency matching function, allowing the second matching network to present a short circuit at the second harmonic while not affecting the fundamental frequency impedance match. This intermediary element enables both functions to coexist with broader bandwidth.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If impedance matching is simplified, then bandwidth operation is broadened, but harmonic termination effectiveness may be compromised

Engineering Contradiction:

Improvebandwidth operationVSAvoidharmonic termination effectiveness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The matching network is divided into two separate functions: a first matching network (30) dedicated to fundamental frequency impedance matching, and a second matching network (40) dedicated to second harmonic termination. This segmentation allows each network to be independently optimized for its specific frequency range, enabling the first network to provide broad bandwidth matching while the second network provides effective harmonic termination without compromising the overall bandwidth.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A series inductor (Ls) is introduced as an intermediary element between the two matching networks. This inductor acts as a frequency-selective element that isolates the second harmonic termination function from the fundamental frequency matching function, allowing the second matching network to present a short circuit at the second harmonic while not affecting the fundamental frequency impedance match. This intermediary element enables both functions to coexist with broader bandwidth.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach simplifies impedance matching at the input of the transistor, allowing for broader bandwidth operation while effectively terminating harmonics, thereby enhancing the overall performance of the amplification system.

Implementation Method 1

a frequency f3n, the series network is inductive and resonates with the first capacitor

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

the series network displays a series resonance at a frequency that is smaller than f1, an RF short is presented by the resonance network at the input terminal at a frequency 2×f2n

Methodology Applied

Scientific EffectSeries resonance: Resonance

Data Source

PatentUS20250158574A1Amplifier With Second Harmonic Termination

Publication Date: 2025.05.15 AMPLEON NETHERLANDS

AI summary

The present disclosure relates to an amplifier configured to amplify signals within a given operational frequency, and further relates to an amplifier system, and to a Doherty amplifier. Examples include one or more resonance networks connected to an input terminal of a transistor of the amplifier that each include a first inductor arranged in between the input terminal and an intermediate node, a first capacitor arranged in between the intermediate node and ground, and a series network arranged in between the intermediate node and ground that includes a second inductor and a second capacitor. A susceptance presented by the one or more resonance networks at the input terminal cancels the input susceptance of the transistor at a frequency within an operational frequency band. In addition, an RF short is presented by each resonance network at a second harmonic of which the corresponding fundamental lies within the operational frequency band.