Click here to go to our main page on microwave history
Click here to go to our page on heating with microwaves
Scan of original Radarange logo, courtesy of Wendy Bock Mitchell
An example of the 1950s commercial Radarange, from courtesy of Raytheon's participation in the 2026 IMS Historical Exhibit
The microwave oven was developed after W.W.II in order to beat swords into plowshares. Perhaps the engineer who is best known for birthing the idea of using microwaves to prepare food was Percy Spencer, of the Raytheon Company, located in Waltham Massachusetts.
Many non-engineers have the perception that a lone inventor goes into a lab for a few months or years, and creates an invention like the automobile or the cell phone by himself. That is almost never the case. Multiple contributors, performing hard work as a team or as individuals, slowly evolve an idea into a product that every once in a while changes the world. Like most other breakthroughs, the microwave oven was a group effort and did not happen overnight.
John Osepchuk
Dr. John Osupchuk was a huge resource on the history of microwaves ovens, and biological effects of microwaves. He died in 2024 at the age of 97. Read his obituary here.
John Osepchuk worked at Raytheon during the 1950s, into the 1980s. His papers on the topic include:
"A History of Microwave Heating Applications", IEEE Transactions on Microwave Theory and Techniques, Vol. MTT-32, No. 9. Sept. 1984, pp 1205-
"The History of the Microwave Oven: A Critical Review", IMS 2009, pp 1397-1400 (it's easy to find this article on the internet...)
His acted as editor on an IEEE/Wiley Press book on biological effects of Electromagnetic Radiation, publishied in 1994. You can often find a copy on Ebay. He retired in 1995 but continued to contribute to professional societies.
John has complained in recent years at IEEE talks that some web sites propose that the microwave oven was invented in Russia, or Germany, but then again, you can find almost any incorrect "fact" you you are looking for on the internet. Below is a video of John talking about the invention of the microwave oven:
John Osepchuk explains some microwave oven history
Also, we refer to The Creative Ordeal, The Story of Raytheon, by Otto J. Scott, published in 1974. This book commemorates the 50th anniversary of the Raytheon Company. Readers should be aware that such autobiographical efforts contain a wealth of information but have been put through a corporate filter, and can often distort the truth either by omission of details, politics, or simple corporate favoritism.
This web page will draw on Osupchuk's and Scott's publications, as well as the US patent office, and remarkably, the accounts of of an eye witness, a girl who consumed far too many hot dogs as her father tinkered on early oven prototypes in the family garage...
Percy Spencer
Percy Spencer 9 July, 1894 – 8 September, 1970
Much work was afoot in the latter days of W.W.II by Daddy Warbucks companies looking for industrial heating applications of microwaves, including diathermy, and industrial heating of products such as inks, glue, and tires. Anyone who worked around the magnetron burn-in stand knew that "soft" objects such as people would start to heat up if they were to stay in the direct path of high-power microwave radiation. Maybe John will send us a picture of the burn-in stand one of these days...
Spencer's thoughts turned to heating food; legend has it that a candy bar melted in his pocket from stray radiation. However, he could not have been thinking of a consumer application, as the high cost of microwave equipment would prevent widespread home use.
Raytheon was not alone in looking at heating applications, General Electric reported on equipment that would thaw and heat frozen meals in a restaurant, using ~1 GHz energy (see Osepchuk).
Spencer's original US patent 2,495,429, Method of Treating Foodstuffs, was filed October 8, 1945 and granted on January 24, 1950. In this patent he points out the choice of frequency which provides high heating efficiency, the size of the cavity, and some superfluous details on the magnetron oscillator itself. He envisioned a conveyor belt for parading the food into the cavity, no mention of safety, or how the radiation might be enclosed or how the food might enter the cavity (like a door). In a second patent 2,480,679 Spencer shows the now-ubiquitous use of microwaves to pop popcorn.
In a later patent 2,540,036, filed March 26, 1948, and granted January 30, 1951, entitled "Food Cooking", Spencer discusses how you might "broil" a lobster in a microwave oven, by violating said lobster with a "pencil like rod", in order so that its tail doesn't curl up which would make harder to cook. Yikes!
The FCC was petitioned by Raytheon and General Electric, who each wanted to propose a frequency for their own work. Thus two frequencies were allocated, 915 +/-25 MHz and 2450 +/-50 MHz. To this day these are the Industrial/Scientific/Medical bands, and billions of cell phones and other wireless devices all communicate within them in the United States and elsewhere. And, of course, billions of meals are prepared each day using 2.45 GHz electromagnetic radiation.
Other Raytheon employees who worked on the microwave oven
The Creative Ordeal credits Lawrence Marshall and Fritz Gross with some of the early work on the "Radarange". Radarange was chosen for the product in an employee competition, combining the words radar and range. (Why they didn't add a "y" to create "Raydarange" to acknowledge the Raytheon company is a mystery to me... - UE). UPDATE: Faithful reader Ed wrote in to report that they DID have a "y" in the design prototypes, as shown in this picture from 1946. Want more pictures like this? Check out the article by Evan Ackerman over at the IEEE Spectrum site.
Marshall was president of the company, so it is safe to say his main contribution was leadership; knowing that this was a project worthy of financial support during tough times. Fritz Gross was chief engineer of the Equipment Division. However, the two often met after hours in the laboratory to experiment with oven concepts. At one point they coupled a magnetron to a galvanized trash can, and used the apparatus to heat water. Later they had a cabinet built, and performed cooking experiments with gingerbread mix (just beginning to appear in stores), the smell was everywhere. The Creative Ordeal also mentions Sam Hathaway (helped refine the design), John Dawson (supervisor of oven and control circuit development) and G.E.M. Bartram (production). Dawson did receive one microwave-related patent, 2,609,497, for a modification of the magnetron itself, really nothing to do with cooking. No other US patents were issued to the others mentioned in this timeframe.
Marvin Julian Bock
Using 2.45 GHz to heat popcorn and lobsters must be first credited to Percy Spencer. However, the engineer that reduced the idea to practice, and developed the first practical, commercially viable microwave oven known as the Radarange, was Marvin Bock. Some details of his life:
Born: December 31, 1914, New York
Marvin graduated from Pratt.
Death: March 27, 1971, Santa Barbara, California.
Electronic Engineer, 29 years with Raytheon
These words are from Marvin's daughter, Wendy.
My dear father, Marvin J. Bock (1914-1971) was an electrical engineer in Percy Spencer's R&D laboratory at Raytheon, and did indeed participate in the development of the microwave oven during the 1940s.
Marvin was a quiet man with a profound sense of integrity. He was an engineer not a manager and was never concerned about his name being on the door. He wanted to be in his laboratory and design systems. I heard that he was very proud of the work he did developing radar equipment for battleships. Until recently I did not understand why he did not pursue his own recognition but I have come to believe that his development of the microwave oven was just not the important invention for him. He went to the World's Fair in Montreal to "present the oven to the world" and died 4 years later, not really having a sense of the importance of the oven.
We had the original microwave in our garage in Needham when I was born in 1945 and I have the silver "Radarange" name plate from that oven.
From what I read in articles, in 1947 Marvin was appointed head of the microwave heating laboratory at Waltham. In 1949 he was named assistant head of the radio frequency and antenna department of Raytheon's Missile Systems Laboratory at Waltham and this is where his focus turned to the Sparrow and Hawk missiles.
We moved to the San Fernando Valley in 1953 and my father worked in Oxnard at Point Mugu. We moved to Santa Barbara in 1956.
This quote is from Osepchuk's 1984 article, which confirms Bock's contribution:
"Enthused Raytheon management sponsored a contest for a name for the microwave oven and the Radarange (TM) was born. Marvin Bock, who later worked with Tom Philips, today's CEO, built the first Radarange, the Model 1132, which provided an output power of 1.6 kW from one water-cooled, permanent-magnet magnetron. This is shown in Fig. 3. Note that it was a free standing white-enameled unit operating from 220 V."
Mr. Bock held five US patents, including one related to microwave heating: 2,516,503 filed December 14, 1946 and issued in July 25, 1950 and titled "Controlling Device for Cooking Apparatus". It discloses a means for shutting off microwave power when a food load is not present in a microwave cooking system, an important feature that the average user wouldn't even know about.
To learn more about engineer Marvin Bock, here's an article from the Santa Barbara News Press, November 16, 1958 "Men of Science" series.
Marvin Julian Bock
Thus from four accounts, Osupchuk, the USPTO, The Santa Barbara News Press, and Marvin's daughter, we know that Marvin Bock did indeed contribute heavily to the development of the Radarange, the world's first commercially successful microwave oven. The Creative Ordeal fails to mention his name even once; as we implied before, corporate history accounts are never 100% complete and accurate.
It should be noted that the microwave oven didn't become a household appliance until 1967, when Raytheon began to market a countertop version of the Radarange though its subsidiary, Amana. You can learn more about the Radarange history at Raytheon's web site history page.
David Arthur Copson
Learn more about David Arthur Copson here!
This came from Tilan (thanks!)
I came across your website and note you are missing information on a contributor to the development of microwave heating. His name is David Arthur Copson, born in Dorchester, MA in 1918. He worked at Raytheon with many of the other folks you listed, and wrote three books, two on Microwave Heating. He was head of the Microwave Heating laboratory in Raytheon (not sure which years, but I'm researching it) and developed the proper methods for heating foods using microwave technology. He holds several patents in the field.
Copson was awarded four US patents for his work in the fifties and sixties. One of his interests was in using microwave energy to assist in freeze-drying, as it provides preferential warming to moist areas of the product without heating areas that are already dry.
Copson was the first or only name on all of his patents, but shared one with Dr. Luther Davis Jr, who went on to become head of the Raytheon Research Division in the 1970s and 80s. Copson wrote the book Microwave Heating in 1975, and you can probably still get a used copy on Amazon.
A quick Google search suggests that Copson lived from 1919 to 1999. If anyone knows more about him we will gladly post more contributed information!
Keishi Ogura
Keishi Ogura was an engineer at Japan Radio Corporation (NJRC), a company founded in 1959 from Japan Radio Corporation. In 1961, Raytheon and Japan Radio Corporation teamed up in a 1/3 (Raytheon) /2/3 (JRC) split of NJRC. The reason for this venture was to find a way to build a cheaper magnetron. Japan was keenly interested in microwave ovens, possibly more interested than the United States, as they noted that Americans eat steak and that's the one thing that cannot be cooked by microwaves. They were also forbidden to work on defense contracts.
Ogura was assigned a seammingly inpossible task... create a better magnetron that was much cheaper to manufacture. With access to Raytheon's magnetron drawings he started over. By 1964 he succeeded, and Japan began developing their own consumer microwaves well ahead of Raytheon. Raytheon played around with building Ogura's design at their war-time Waltham factory but could only get the cost down to $125 versus NJRC's $25. Raytheon launched their Amana microwave product in 1967, and soon all of their magnetrons were sourced from Japan.Below is an image of Raytheon's 1500W CW commercial magnetron, the QK-217, circa 1950s. This is what Ogura started with (and virtually ignored). Note that it is missing its magnet and waveguide flange.
An example of a 1950s magnetron used in the Radarange, courtesy of Raytheon's participation in the 2026 IMS Historical Exhibit
An image of a complete QK-217 tube can be found on page 131 of May 1949 Electronics Magazine, which you can find here. We cut and pasted it below. Maybe Raytheon can look in the junk drawer for the missing pieces?
References
1. Otto J. Scott, "The Creative Ordeal The Story of Raytheon".Antheneum, 1974.
2. John Osepchuk, editor, "Biological Effects of Electromagnetic Radiation", IEEE/Wiley Press,1994.
3. Here's an excellent reference on tehhistory of the microwave oven: "Breakthroughs" by P. Ranganath Nayak and John M. Ketteringham, 1994. Subtitled "How Leadership and Drive Create Innovations that Sweep the World", you can find a used copy of it on Amazon, or you could cheat and look at a copy someone uploaded here. Chapter eight is devoted to the story of the microwave oven. NJRC is first mentioned on page 176. Trust us, it is worth a read!