Understanding the basics of solid-state RF power

Explore answers to the most common questions we receive about RF heating and drying and solid-state RF power. If you don’t see what you’re looking for below, please contact us.

Radio Frequency (RF) heating is a technology wherein rapidly varying electric fields produce heat within a targeted material. RF heating (also known as dielectric heating) shares much in theory with a domestic microwave oven, however, it is very different in practice with significant advantages when employed on a large scale. RF technologies use longer wavelengths for instant heat generation, better penetration, and more even heating from within.

A solid-state radio frequency power generator is a device that converts AC power from the power grid into radio frequency (RF) power for industrial heating, drying, and other similar purposes.

Solid-state RF power generators use transistor technology as opposed to vacuum tube technology. Solid state outperforms legacy vacuum tube technology on every level by offering pinpoint precision, greater flexibility, digital control, unmatched energy efficiency, and a 20-year+ lifespan.

The difference between these RF technologies is that solid-state produces RF power using transistors instead of vacuum tubes. The vacuum tubes used in many RF power generators are high-power versions of the vacuum tubes used in early radio and television equipment.


One of the biggest issues with vacuum tube systems is they have a high failure rate*, causing system downtime and lost production capacity. They also require periodic replacement as their power and efficiency degrade over time.


Modern solid-state equipment requires virtually no physical maintenance and can last for over 20 years. Energy efficiencies of 95% or higher are typical in our designs, whereas vacuum tube technology is generally 50% to 60% efficient. Not only can our technology reduce the carbon footprint of the process, but electrical cost reductions of 50% are also often achieved.


Because our solid-state RF generators use digitally controlled amplifiers, thus providing precise power control, process control is significantly improved. Our control system monitors and adjusts the power thousands of times per second, compensating for external variations. This results in improved product quality and consistency.


(*) As published in MIL-HDBK-217F, the US military publication for predicting equipment reliability, a vacuum tube rated greater than 2000 watts has a mean time to fail (MTTF) of only 4000 hours or 167 days. Comparatively, a silicon MOSFET power transistor rated greater than 250 watts has a mean time to fail of 16 million hours or 1826 years.

Our technology makes solid-state affordable, and our solid-state RF generators offer opportunities for significant ROI. Examples include reduced electrical energy cost, smaller footprint, less process/product waste, more reliable and consistent processes, the ability to capture and feedback process data to improve process control, reduced downtime for scheduled and unscheduled maintenance, and the elimination of periodic vacuum tube replacements.

Additional savings will result from less product waste and improved product quality. Also, the cost of downtime resulting from vacuum tube system failures should be considered. A solid-state RF power generator minimizes downtime, because it requires no physical maintenance and has a 20 year+ lifespan.

To find out how much you could save by upgrading to solid-state RF power, contact us.

Most systems can be upgraded to solid-state technology. Our engineers are able to custom-build an APG™ series generator to create the ideal configuration and technical integration with your current processes. While it will be designed to be plug and play, we’re always available to perform the installation for you.

When properly installed and used for its intended purposes, our solid-state RF generator technology is completely safe. We ensure our equipment meets or exceeds all safety regulations and standards for the areas in which it is sold. We also test our equipment during the installation process to verify there are no issues.

In the case of a simple replacement of an existing vacuum tube RF generator-based system, we would typically offer a solution that operates at the same frequency as the installed system, whether that be 6.78 MHz, 13.56 MHz, or 27.12 MHz.

Many systems working at 27.12 or 40 MHz may be converted successfully to lower frequencies. We can also provide other frequencies, currently in the range of 1 MHz to 100 MHz, for applications as varied as space propulsion and nuclear fusion.

To find out what frequency you should be operating on, contact us.

Power is the specification that determines the amount of heat the generator can deliver to the product. We define power at the generator output, while vacuum tube suppliers typically rate power based on the DC input power to the vacuum tube.

Because of the relatively poor energy efficiency of a vacuum tube generator, a solid-state RF generator will typically deliver 40% more heating capacity compared to a vacuum tube generator of the same power rating.

Frequency refers to the number of times per second the RF wave vibrates. For example, a 6.78 MHz generator produces 6.78 million vibrations per second. In most cases, a given product may be processed effectively over a relatively wide range of frequencies.

Our APG™ series generators have a sophisticated control system that measures the RF power thousands of times per second, assuring repeatability and reducing process variations. Having a repeatable process improves product quality and reduces waste.

Solid-state generators have an expected lifespan of at least twenty years, with significantly reduced operating costs. We have successfully replaced vacuum tube technology with solid-state technology in several markets, and there has never been a case of the customer returning to its previous technology.