RF Energy in Daily Life Part 2: Plasma Lighting

Dec. 13, 2016

BlogPlasmaLights.jpgAs the value of Gallium Nitride (GaN) technology becomes recognized in the commercial microwave and radio frequency (RF) market, potential applications abound, perhaps most notably in the RF energy sector, as we highlighted recently in an earlier blog post. RF energy uses controlled electromagnetic radiation to power different process, efficiently replacing today’s magnetron tubes with a solid-state solution that offers low-voltage drive, semiconductor-type reliability, and a smaller form factor, in addition to fast frequency, phase and power agility, complemented by hyper-precision. This technology delivers an unprecedented control range, even energy distribution, and fast adaption to changing load conditions.

Among the exciting applications benefiting from RF energy is plasma lighting, which promises to be the next evolution in the lighting market, and has included milestones like the standard Philips lightbulb and LED lighting. Plasma lighting is a light without electrodes, formed by a noble gas discharge and energized by RF power. It was invented by Tesla as a result of a study on high voltage, during which he experimented with high frequency currents in glass tubes. The electrical field is directed by a special type of waveguide, exciting the plasma.

Plasma lights provide key advantages over alternative mainstream light sources. They’re much smaller in size than the conventional fluorescent and high-intensity discharge (HID) lamps commonly used today to light large areas, and they provide much higher luminaire efficiencies. These qualities enable plasma lights to deliver high levels of visual acuity while requiring fewer light fixtures and consuming less power.

Since their invention, plasma lights have been powered by magnetrons, which are estimated to have a lifespan average of 500 to 1000 hours. This is an important consideration when assessing the value of plasma lights, so it’s worthwhile to run some numbers.  The United States Naval Observatory offers a tool to calculate the number of hours of darkness (or time the entire Sun is below the horizon) in a given time period. In Los Angeles, California, there was an average of 10 hours and 9 minutes of daily darkness for the month of August this year, totaling almost 313 hours of darkness for one month. If left on continuously during these periods of darkness, plasma lights powered by magnetrons will have reached the end of their lifespan anywhere from 2 months at a minimum to 4 months at a maximum. As a result, applications like outdoor, street, stadium or area lighting would not benefit from magnetron-based plasma lighting due to the excessive cost of replacing bulbs.

However, utilizing the performance benefits of GaN technology, solid-state RF energy-based plasma lighting vastly extends the lifespan of the light source, giving plasma lights previously unreachable market opportunities. As a result of the efficiency and longevity of solid-state RF energy, plasma lighting can now offer extreme value for wide-area lighting applications.

Not only does RF energy powered by GaN offer greater efficiency and a longer lifespan, it also enables controllable energy. The hyper-precise lightbulb powered by RF energy is able to adapt to the time of day, or the motion of a passing person or vehicle, and transition the light emitted accordingly. With RF energy, electricity would no longer be wasted on vacant areas, further extending the longevity of a lightbulb.

Although this is an appealing concept, historically the cost structure of a solid-state chip has been more expensive than a magnetron, making RF energy applications a luxury. However, with the superior efficiency and gain performance of MACOM GaN—available on silicon wafers at silicon cost structures—plasma lighting has an opportunity to dominate the lighting market for the first time.

By improving the efficiency and controllability of plasma lighting with RF energy, at a cost that’s lower than legacy technology, the upgrade to an energy-saving solution is as simple as changing a lightbulb. Existing street light fixtures, wiring and supports should be fully compatible with RF plasma-based lighting and require no modifications. In Los Angeles and around the world, we can reap the benefits of hyper-precise lighting to achieve enormous energy savings! The value of RF energy in plasma lighting, combined with GaN technology, is virtually limitless.

Learn more about RF Energy and products like MACOM’s recently announced 300W GaN Power amplifier at: www.macom.com


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