Injection-Locked Subcritical Magnetron RF Power Range Control
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Solution Overview
Problem
Magnetron power sources for particle accelerators lack efficient control over a broad range of output RF power and phase, limiting their application in variable load conditions and introducing inefficiencies by diverting power to dummy loads.
Innovation Solution
Operating a magnetron with a cathode voltage below the critical voltage and using a strong injection phase-locking signal to achieve broad power control through small changes in cathode voltage, implemented in a 2-stage magnetron system with phase-modulated injection-locking and high-voltage power supply feedback loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a magnetron operates with constant output power using regulated cathode voltage, then the magnetron provides stable RF power output, but the output power cannot be efficiently controlled over a broad range
Solution Approach 1:
The patent changes the operating parameter of cathode voltage from constant (above critical voltage) to variable (below critical voltage), enabling broad output power control range. By operating below the critical voltage and using injection phase-locking, the magnetron can efficiently produce variable power without diverting to dummy loads, directly resolving the contradiction between power control range and energy efficiency.
2Adaptability or versatility
If a magnetron operates below critical voltage with injection phase-locking, then broad power control range is achieved, but the system requires strong injection signals and precise voltage control
Solution Approach 1:
The patent implements feedback control through phase-locking the magnetron to a reference signal. The injection phase-locking mechanism provides automatic frequency and phase control, stabilizing the magnetron operation below critical voltage. This feedback system manages the complexity by automatically adjusting parameters to maintain stable operation across the broad power range.
Solution Approach 2:
The patent applies preliminary action by pre-locking the magnetron frequency to the reference signal before power modulation. The strong injection signal establishes the operating frequency and phase in advance, allowing subsequent power control to proceed smoothly without instability, thus managing system complexity.
3Power
If a magnetron operates in free running mode above critical voltage, then the magnetron produces sufficient power output, but the power control range is limited
Solution Approach 1:
The patent inverts the conventional operating approach by operating below critical voltage instead of above it. Conventionally, magnetrons operate above critical voltage for sufficient power output, but this patent reverses that paradigm - using injection phase-locking to enable stable operation below critical voltage, thereby achieving both sufficient power and broad control range simultaneously.
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 enables efficient control of output power over a 10 dB range with high efficiency and precise frequency stability, reducing noise and eliminating the need for dummy loads, making it suitable for superconducting RF accelerators and other applications.
Implementation Method 1
A magnetron is an oscillator that produces coherent microwave radiation
Implementation Method 2
regulated cathode voltage power source
Implementation Method 3
an injection phase-locking signal RF signal is fed into the magnetron through the magnetron output antenna
Implementation Method 4
a fixed magnetic field
Data Source
AI summary
A system and method of operating a magnetron power source can achieve a broad range of output power control by operating a magnetron with its cathode voltage lower than that needed for free running oscillations (e.g., below the Kapitsa critical voltage or equivalently below the Hartree voltage) A sufficiently strong injection-locking signal enables the output power to be coherently generated and to be controlled over a broad power range by small changes in the cathode voltage. In one embodiment, the present system and method is used for a practical, single, frequency-locked 2-magnetron system design.