Milestone-Proposal:Microwave Oven
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Docket #:2024-05
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To the proposer’s knowledge, is this achievement subject to litigation? No
Is the achievement you are proposing more than 25 years old? Yes
Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes
Did the achievement provide a meaningful benefit for humanity? Yes
Was it of at least regional importance? Yes
Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes
Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes
Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes
Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes
Year or range of years in which the achievement occurred:
1945-1997
Title of the proposed milestone:
Microwave Oven, 1945-1997
Plaque citation summarizing the achievement and its significance:
200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.
IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.
In what IEEE section(s) does it reside?
Boston Section
IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:
IEEE Organizational Unit(s) paying for milestone plaque(s):
Unit: IEEE Boston Section
Senior Officer Name: Maíra Marques Samary, 2024 IEEE Boston Section Chair
Unit: IEEE Boston Section
Senior Officer Name: Robert J. Alongi, Jr., Business Manager
IEEE Organizational Unit(s) arranging the dedication ceremony:
Unit: IEEE Boston Section
Senior Officer Name: Maíra Marques Samary, 2024 IEEE Boston Section Chair
Unit: IEEE Boston Section
Senior Officer Name: Robert J. Alongi, Jr., Business Manager
IEEE section(s) monitoring the plaque(s):
IEEE Section: IEEE Boston Section
IEEE Section Chair name: Maíra Marques Samary, 2024 IEEE Boston Section Chair
Milestone proposer(s):
Proposer name: Dr. Joseph P. Campbell
Proposer email: Proposer's email masked to public
Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.
Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):
Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.
Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need.
Are the original buildings extant?
Details of the plaque mounting:
How is the site protected/secured, and in what ways is it accessible to the public?
Who is the present owner of the site(s)?
What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include justification here. (see section 6 of Milestone Guidelines)
S T A R T I N G D R A F T
- personal names to be removed and to be taken out of first-person narrative form*
Almost everyone has a microwave oven today, or has at least had food processed in such an oven. These ovens are found in homes, restaurants, industrial and medical facilities, etc. Where did they come from? Who developed them, and when? Actually, a Vice President and engineering manager at Raytheon Company in Waltham, Massachusetts, by the name of Percy Spencer, holds the first patent on a microwave oven. He conceived it in November 1945 while watching the manufacture and processing of a magnetron microwave tube. These tubes were the heart of all early radar systems, generating the high-power microwave energy in short pulses that were transmitted and bounced off targets to track and identify ships and aircraft in WW II. They were being produced in large quantities by Raytheon at that time.
Other people had noticed the heating effect of microwaves. Radar technicians had found that they felt warm when standing in front of their radar antennas. Some German soldiers even were reported to warm their meals by placing them in front of the antennas. However, Percy Spencer was the first to assign development engineers, create a product, and pursue it for many years to make an oven practical for home use.
How did I get involved in microwave oven development? After graduating from OHS in 1940 at age 16, earning a degree in Electrical Engineering from Union College in 1944, and spending 2 years in the U.S. Navy as a Radar/Sonar Specialist Officer (including training at Harvard and MIT and assignment to the Naval Research Lab), I joined Raytheon in October 1946 as a Magnetron Development Engineer. I worked there 43 years, mostly on high-power microwave tube designs for new radar systems. I also worked on marine and airport radars, missile guidance and weather radars. In the late 1960s and early 1970s I also contributed to the magnetron work for the microwave oven. At one time I had as many as 40 ovens assigned to "life tests," running under various stress conditions and on-off cycles, to evaluate our design improvements and discover any weaknesses. (Not all 40 were running at once. Some were undergoing construction changes, circuit modifications, or magnetron tube revisions, but it was a very busy activity. Certain combinations of on-off cycles or power loads in the oven could cause short life – unacceptable in any use. The object was to achieve the equivalent of ten years of typical household usage.)
As shown in Figures 1 and 2, the earliest microwave ovens were large and heavy, about the size of a common home refrigerator. They were based on tubes and circuit technology used in WW II radars and were really only suitable for industrial use, or in restaurants, military establishments, hospitals, railroad dining cars, etc. However Raytheon did some business in those areas for several years, while trying to optimize the ovens for the much broader home market. Fortunately, Raytheon Company acquired Amana Refrigeration Co. in 1963 with the purpose of using their expertise in manufacturing home appliances to convert the ovens for more practical home use.
George Foerstner, President of Amana (see Figure 3), immediately made recommendations for major redesigns, which resulted in smaller size (about the size of an air conditioner; see Figure 4), air cooling instead of inconvenient water cooling, 120-volt operation (readily available in homes, versus the earlier 220-volt models), and lower cost (under $500). A new smaller and less expensive magnetron also appeared at this time from a Raytheon subsidiary, New Japan Radio. Miniaturization of the magnetron over the years is illustrated in Figure 5. Raytheon's magnetron development technology, such as seen in Figure 6, provided important engineering background for these design advancements. Moreover, by now small solid-state rectifier diodes could replace the bulky vacuum-tube rectifiers that converted the high-voltage AC to DC to operate the magnetrons in the oven. All of these features resulted in the ovens becoming much more attractive for home use. As shown in Figure 3, the Raytheon-Amana RadaRange oven, which first appeared on the market in 1967, was a tremendous success, and home microwave oven sales surged dramatically.
Raytheon licensed other U.S. companies, such as Litton, Tappan, GE, etc., to use similar design approaches and manufacture ovens. The search for still newer, better and cheaper designs continued. Soon companies began transferring manufacture overseas where labor rates were cheaper, and today nearly all microwave ovens are built in China, South Korea, Indonesia, etc. While a typical model of a 1946 oven might have cost as much as several thousand dollars, the 1967 RadaRange cost just under $500. I bought a small model of an Asian oven a few years ago for the Raytheon Archive display at a total cost of $27.00! U.S manufacturing costs cannot approach this.
Meanwhile, the use of high-power microwave energy for various commercial applications has turned into a worldwide industry. Companies such as Hormel Foods, Firestone Tires, Frito-Lay, and myriads of food, medical and materials processing users have found the technology beneficial and profitable. As shown in Figure 7, these ovens are huge, however, with some magnetrons delivering as much as 100 kilowatts of power (100 times more powerful than a home microwave oven) and employing conveyor belts to speed production. The scope of this industry is reflected by international conferences, that attract attendees from across the world, including the US, Switzerland, Israel, Brazil, China, Japan, India, Russia, England, Germany, and France. At the recent Annual Conference of the International Microwave Power Institute (IMPI), held in Cambridge, MA, on August 10, 2006, I was honored to give its keynote speech on the subject "Invention of the Microwave Oven at Raytheon Company."
Raytheon eventually sold Amana in order to withdraw from some commercial markets and concentrate more on the defense industry, and today is a major defense contractor with nearly 80,000 employees worldwide. Amana is still an important appliance manufacturer, with products in the microwave power field. I am glad to have participated in the development phase of microwave ovens. It was an exciting and educating experience and left me with a feeling of having contributed to a product that benefits many people.
What obstacles (technical, political, geographic) needed to be overcome?
What features set this work apart from similar achievements?
Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.
[a] Alan R. Earls and Robert E. Edwards, "Raytheon Company: The First Sixty Years," (ISBN-13: 978-1531622145) Arcadia, 2005. [b] Robert E. Edwards, "Invention of the Microwave Oven at Raytheon Company," keynote speech, Annual Conference of the International Microwave Power Institute (IMPI), Cambridge, MA, 10 August 2006 [c] Evan Ackerman, "A Brief History of the Microwave Oven: Where the “radar” in Raytheon’s Radarange came from," IEEE Spectrum, 30 Sep 2016 (Updated 11 Jan 2024), https://spectrum.ieee.org/a-brief-history-of-the-microwave-oven [d] Dana Canedy, "Sale to Remove Raytheon From Consumer Appliances," The New York Times, 15 Jul 1997, https://www.nytimes.com/1997/07/15/business/sale-to-remove-raytheon-from-consumer-appliances.html
Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to ieee-history@ieee.org. Please see the Milestone Program Guidelines for more information.
Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to ieee-history@ieee.org with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).
Please recommend reviewers by emailing their names and email addresses to ieee-history@ieee.org. Please include the docket number and brief title of your proposal in the subject line of all emails.
