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Will Today’s Microwave Oven Soon be a Thing of the Past, Part 2?

How can solid-state RF energy impact the microwave oven? We set out to answer that question.

Recently I wrote an editorial titled, “Will Today’s Microwave Oven Soon Be a Thing of the Past?” That piece discussed the possibility of microwave ovens based on solid-state RF energy, which would essentially replace traditional magnetron-based microwave ovens. The potential benefit of healthier cooked food was specifically mentioned.

A few readers have since commented in regard to that editorial. One specific question concerns exactly how solid-state RF energy can cook healthier food. Since not much detail was offered in that editorial piece, I thought it would be beneficial to write another article in an attempt to provide a better explanation. This article will hopefully shed some light on the topic of solid-state RF energy.

Meet the Skeptic

Of course, it is common that any new technology will lead to skepticism. Solid-state RF cooking can certainly fit that description, as some may seriously doubt the legitimacy of microwave ovens based on solid-state RF energy. One question could simply be this: How can solid-state cooking help to enable healthier eating? Let’s try to answer that question.

As mentioned in the previous editorial, MACOM (www.macom.com) is one company that is at the forefront of solid-state RF energy (see figure). Mark Murphy is currently the company’s senior director, RF power. He says, “Anytime food is heated, its nutrients and state can be degraded if the cooking process is not controlled properly. That is why precise temperature control is so important for healthier cooking. Microwave ovens that leverage solid-state power amplifiers are superior to conventional magnetron-based microwave ovens in that they enable far greater precision and control of the directed energy, which helps to preserve the nutritional integrity of the food.”

Although magnetron-based microwave ovens have been used for many years, Murphy can plainly state their shortcomings. He explains, “Magnetron-based microwave ovens aren’t equipped to measure and adapt to energy that’s absorbed by or reflected from the food into the cavity as it cooks. They instead deliver open-loop, crudely-averaged heating that’s assisted by a rotating turntable at the base of the cavity. This imprecise energy delivery often results in overcooking and hot spots that can lower the food’s nutritional value.”

Murphy continues, “By using multiple solid-state power amplifiers and antennas with closed-loop feedback to adjust for precise energy absorption, the energy can be directed with greater precision to exactly where it’s needed and in a controlled way that ensures optimal temperature control. Rather than relying on moisture sensors that measure humidity in the cooking cavity—an indirect mode of measurement that’s sometimes implemented in modern magnetron-based microwave ovens—solid-state microwave ovens measure the properties of the food itself while it cooks and adapt accordingly. This promotes the retention of the nutrients, moisture, and flavors of the food.”

Economics of Solid-State Microwave Ovens

Another possible question concerning solid-state RF cooking is with regard to its economic viability. In other words, will solid-state microwave ovens be economical for the commercial market? According to Murphy, the short answer is yes. He states, “The adoption of solid-state microwave ovens will commence in the industrial and commercial cooking market, where the value that these systems provide will be well worth the modest increase in cost. Customers will gain significant advantages centric to system reliability, food processing speed, and throughput.”

This microwave oven based on solid-state RF technology was demonstrated at IMS 2017.

 

Murphy believes that reliability is a major benefit of solid-state RF cooking. He notes, “With regard to system reliability, solid-state RF transistors can provide 10X longer lifespans that magnetrons—this is a major benefit in 24/7 production environments where frequent magnetron failures can slow production and require numerous expensive service calls. By eliminating the rotating platters common to magnetron-based microwave ovens, system reliability is further increased due to the reduction of mechanical moving parts, which are a common point of failure.”

Greater reliability is not the only benefit of solid-state RF cooking, according to Murphy. He adds, “Food processing speed and throughput are increased due to solid-state microwave ovens’ ability to heat and cook food much faster than magnetron-based systems, owing to the rapid energy transfer enabled by RF power. Solid-state RF technology is particularly valuable for food defrosting processes, enabling food to be defrosted much faster and more evenly than it can today without drying or damaging the food.”

To sum it all up, Murphy does indeed believe that microwave ovens based on solid-state RF energy will eventually find their way into homes. He says, “With continued innovation in solid-state GaN based RF technology and cost structure improvements, this technology will eventually migrate to consumer kitchens, and in so doing will change our perceptions of the modern microwave oven. Its value will evolve from that of a simple heating device, to a device that’s capable of cost-effectively cooking healthier, multi-course meals with unprecedented efficiency. In a way, this evolution will do for cooking what the smartphone did for the way we use our cell phones.”

In summary, this article hopefully answered some questions that one may have concerning the possibility of cooking based on solid-state RF energy. Some interesting points were made in an attempt to validate this technology. While everyone still may not be convinced, one thing can be said: it will be interesting to see how solid-state RF cooking unfolds in the future.

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