Switchable T/R Module GaN HPA Dwell Time

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Solution Overview

Problem

In Gallium Nitride (GaN) based radar systems, the slow decay of drain voltage in High Power Amplifiers (HPAs) during the transmit mode causes a delay before switching to the receive mode, which increases the dwell time between transmit and receive modes, hindering system performance.

Innovation Solution

A switchable transmit/receive module with a common RF port switch terminated into a matched load when both transmit and receive enables are off, allowing the drain voltage to decay quickly and enabling faster switching to the receive mode by shutting off the transmit path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If GaN HPA is used to achieve higher power output, then transmit power is improved, but drain voltage decay becomes slow causing increased dwell time

Engineering Contradiction:
Improvetransmit powerVSAvoiddwell time
Core Design Contradiction:
PowerVSLoss of time

Solution Approach 1:

The patent extracts the drain voltage decay problem from the GaN HPA system by introducing a separate bleeder circuit that independently manages the voltage discharge process. This allows the HPA to maintain high power output while the bleeder circuit handles the time-critical voltage decay function, resolving the contradiction between power output and dwell time reduction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bleeder circuit acts as an intermediary component between the GaN HPA and the rest of the radar system. It mediates the voltage decay process by providing a controlled discharge path, allowing the HPA to deliver high power during transmit while enabling rapid voltage decay during the transition to receive mode, thus reducing dwell time without sacrificing transmit power capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If drain voltage decays slowly in GaN HPA, then power stability is maintained, but switching speed to receive mode decreases

Engineering Contradiction:
Improvepower stabilityVSAvoidswitching speed
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The patent segments the voltage management function by separating the power delivery path from the voltage decay path. The HPA maintains power stability during transmit operations, while the bleeder circuit independently controls the voltage decay rate during mode transitions. This segmentation allows both power stability and fast switching speed to be achieved simultaneously without compromising either function.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3440476B1Switchable transmit/receive (t/r) module
Publication Date: 2022.10.05 RAYTHEON CO
  • EP3440476B1 patent drawingFigure 1
  • EP3440476B1 patent drawingFigure 1A
  • EP3440476B1 patent drawingFigure 1B

AI summary

A transmit/receive module having a switch, a load and a controller for coupling radar energy fed to switch to the load during a time interval subsequent to the controller producing a transmit enable signal to the transmit/receive module and prior to the controller producing a receive enable signal to the transmit/receive module.