Microwave ovens have used the same basic design for decades, but, as we described
this video, upgrading to solid-state electronics promises to change how we cook food.
Today’s ovens are powered by a magnetron, which is a device originally
developed for World War II radar systems. Magnetrons use old-fashioned vacuum
tubes (valves) to generate the necessary short-wavelength radio waves for
cooking, and this leads to certain drawbacks.
Magnetrons don’t cook very well
Magnetrons don’t always heat evenly, so food can be overcooked in
some places and raw in others, and they deliver less power when they’re
warm, which means the same dish can require more time to cook if the oven has
been in heavy use.
Magnetrons also have a relatively short lifespan – about 500 hours in
the average household oven, and about a year of continuous use in commercial
environments – and they get weaker as they age, so food takes longer to
cook before the oven stops working entirely.
Using solid-state electronics instead
The good news, though, is that magnetrons can finally be retired. Recent
developments in wireless communication have yielded radio frequency (RF)
components – including the high-power transistors needed for
microwave generation – that deliver higher efficiency, greater power
density and improved voltage capability, at prices that are competitive
enough for consumer appliances like microwave ovens.
Replacing magnetrons with solid-state electronics promises to transform
microwave cooking, with appliances that cook more evenly, more
consistently, more efficiently and with more predictable results. Here are
some of the benefits:
Fewer hot spots – Using solid-state RF for precise phase
control makes it possible to redirect hot spots, for more uniform heating
and greater efficiency. Multi-source phase locking, a concept used in mobile
phones to improve signal delivery, adds another level of control and
Higher accuracy and stability – With solid-state components,
power control is more linear, so there’s less variation in
temperature within a cooking cycle. Also, the latest modulation and digital
signal-processing (DSP) techniques make the microwave signal more accurate
and more stable.
Higher efficiency – Solid-state RF supports frequency tuning
(used in Bluetooth accessories), which makes better use of the frequency
spectrum to increase efficiency. It also makes it easier to modify the
oven’s operation based on what’s being cooked, since a bag of
popcorn is different from a raw potato or a frozen turkey.
Better cooking algorithms – Sensor technology, used to
measure the reflection of RF power, lets the oven become a measurement
system and supports the development of new, closed-loop algorithms that can
monitor, modify and optimize cooking in real time.
Longevity – Solid-state RF components, which are used in
rugged applications like cellular base stations, have to operate without
interruption for as long as 15 years, so they’re designed for