Reflex Klystron Calculator | Formula, Power & Efficiency

The reflex klystron is a microwave vacuum tube oscillator widely used for generating stable, low power microwave signals in laboratory instruments, local oscillators and educational setups. It operates on the principle of velocity modulation and electron bunching within a single resonant cavity, with feedback provided by a repeller electrode that reflects electrons back toward the cavity gap.

Unlike multicavity klystrons, the reflex klystron achieves oscillation using a single cavity, making it compact and analytically tractable for design and performance evaluation. This page provides a reflex klystron calculator and its formula.

EXAMPLE:

• INPUTS:
  • Frequency (GHz) = 10
  • Beam voltage (V) = 300
  • Beam current (mA) = 15
  • Mode = 2.75 ( = 11/4)
  • Repeller spacing (meter) = 0.001 (=1mm)
• OUTPUTS:
  • Power = 0.651 Watt
  • Repeller Voltage = 124.5 V
  • Efficiency = 14.47

Reflex Klystron Equation

The following equation or formula is used by the reflex klystron calculator:

Summary: This reflex klystron calculator provides a practical and physics based evaluation of key performance parameters using fundamental microwave tube theory.

The calculator highlights how:

• Repeller voltage controls electron transit time and mode selection
• Mode number governs oscillation stability and output characteristics
• Beam voltage and current directly influence RF power generation
• Repeller spacing affects bunching conditions and efficiency

Such calculations are essential for understanding mode behavior, power limitations and efficiency trade offs in reflex klystron oscillators.