Compared to capacitors utilizing other dielectric materials, vacuum capacitors are characterized by high voltage withstand capability, compact size, low loss, and stable, reliable performance. Their unique advantages can be summarized in the following aspects:
Rated Voltage
Due to the high dielectric strength of a vacuum-combined with inherent resistance to dust contamination and moisture-vacuum capacitors achieve significantly higher rated voltage values for a given physical size and capacitance compared to other types. These voltages can reach levels as high as several hundred thousand volts.
Low Loss and High Rated Current
Because these capacitors employ a vacuum dielectric, a low-loss insulating envelope, and an oxygen-free copper electrode structure, they are capable of handling very high radio-frequency (RF) currents-even at extremely high frequencies-under standard convective cooling conditions. When equipped with a specialized water-cooling system, the RF current capacity can reach up to several thousand amperes.
Space Efficiency
For any given capacitance and rated voltage value, vacuum capacitors occupy the absolute minimum amount of physical space.
Wide Tuning Range
The ratio of maximum to minimum capacitance can reach as high as 150:1, spanning a range from a few picofarads to several thousand picofarads; this makes them an ideal component for applications requiring a wide tuning range.
Self-Healing Capability Against Overvoltage
Vacuum capacitors are capable of withstanding momentary overvoltage transients-conditions that would otherwise cause permanent damage to other types of capacitors.
High-Altitude Operational Capability
The vacuum-sealed construction enables vacuum capacitors to operate effectively in high-altitude environments without any degradation in their performance characteristics.