of the microwave oven
here to go to our main page on microwave history
here to go to our page on heating with microwaves
Scan of original Radarange logo, courtesy of Wendy Bock Mitchell
New for March 2013! Learn about David Arthur Copson
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.
One of the subject matter experts
on this topic is John Osepchuk, who worked at Raytheon during the
60s, 70s and 80s. His papers on the topic include:
"A History of Microwave
Heating Applications", IEEE Transactions on Microwave Theory
and Techniques, Vol. MTT-32, No. 9. Page 1205
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 anything you want on the internet. We hereby invite
John to give us a hand telling the real microwave oven story!
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 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
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
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).
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 issed to the others mentioned
in this timeframe.
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
Marvin graduated from Pratt.
Death: March 27, 1971, Santa Barbara, California.
Electronic Engineer, 29 years with Raytheon
These words are from Marvin's
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
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
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
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!