GaN HEMT RF Switch for High Power Low DC Consumption

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Solution Overview

Problem

Existing high power RF and microwave switching devices, such as PiN diode switches, consume high dc power and have limited frequency bandwidth, while GaAs HEMT switches cannot handle high RF power levels due to low voltage handling, posing challenges for efficient signal redirection in microwave systems.

Innovation Solution

A monolithic high power RF switch using gallium nitride high electron mobility transistors (HEMTs) on a silicon carbide substrate, with a serpentine gate pattern and spiral inductor loops, capable of handling over 20 watts of RF power with low dc power consumption and wide frequency range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If PiN diode switches are used to handle high power RF signals, then power handling capability is improved, but dc power consumption increases significantly

Engineering Contradiction:

ImproveRF power handling capabilityVSAvoiddc power consumption

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The patent changes the material parameter from conventional PiN diode semiconductor to gallium nitride (GaN), which fundamentally alters the device characteristics. GaN enables high power handling with low dc power consumption by providing higher breakdown voltage and lower on-resistance, directly resolving the contradiction between power handling capability and dc power consumption

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure combining gallium nitride high electron mobility transistors (HEMTs) with spiral inductor loops and resistive elements. This composite design integrates the high power handling capability of GaN HEMTs with the power-saving characteristics of resistive switching, achieving both high RF power handling and low dc power consumption simultaneously

Inventive Principle:

Principle #40Composite materials

2Power

If PiN diode switches are used for high power RF signals, then power handling is improved, but frequency bandwidth is limited

Engineering Contradiction:

ImproveRF power handling capabilityVSAvoidfrequency bandwidth

Core Design Contradiction:

PowerVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic switching control using gate voltage modulation of the GaN HEMT. The switch can be rapidly transitioned between on and off states by applying control voltages to the gate terminal, enabling operation across a wide frequency bandwidth. The dynamic nature of the FET switching mechanism allows adaptation to different frequency requirements while maintaining high power handling capability

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If GaAs HEMT switches are used to reduce dc power consumption, then energy efficiency is improved, but voltage handling capability decreases

Engineering Contradiction:

Improvedc power consumptionVSAvoidvoltage handling capability

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The patent changes the material parameter from gallium arsenide (GaAs) to gallium nitride (GaN), which fundamentally improves the voltage handling capability. GaN provides higher breakdown voltage and higher electron saturation velocity compared to GaAs, enabling the switch to handle high RF power levels while maintaining low dc power consumption characteristics

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 GaN HEMT switch achieves linear transmission of over 20 watts of RF signal with minimal loss and mismatch error across a broad frequency band, consuming less than 1 mW of dc power and operating with high efficiency, addressing the limitations of existing technologies.

Implementation Method 1

gallium nitride high electron mobility transistors (HEMTs)

Methodology Applied

Scientific EffectHigh electron mobility:

Implementation Method 2

spiral inductor loops

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2572450B1High power gallium nitride field effect transistor switches

Publication Date: 2019.02.20 WOLFSPEED INC

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AI summary

A monolithic high power radio frequency switch includes a substrate, and first and second gallium nitride high electron mobility transistors on the substrate. Each of the first and second gallium nitride high electron mobility transistors includes a respective source, drain and gate terminal. The source terminal of the first gallium nitride high electron mobility transistor is coupled to the drain terminal of the second gallium nitride high electron mobility transistor, and the source terminal of the second gallium nitride high electron mobility transistor is coupled to ground. An RF input pad is coupled to the drain terminal of the first second gallium nitride high electron mobility transistor, an RF output pad is coupled to the source terminal of the first gallium nitride high electron mobility transistor and the drain terminal of the second gallium nitride high electron mobility transistor.