The MIT Radiation Laboratory - RLE's Microwave Heritage

RLE currents Vol. 4, No. 2  (Spring 1991)

Contents:

The MIT Radiation Laboratory

The recent Persian Gulf conflict vividly demonstrated America's high-tech arsenal. Although laser-guided smart weapons and Patriot missiles had not been previously used in actual combat, their superiority on the battlefield was evident. While they may not have single-handedly won the war, they did minimize civilian casualties by accurately pinpointing strategic targets and may have curtailed hostilities by challenging traditional military tactics.

Fifty years ago, the new technology of that era would also change the nature of warfare. Even as fighting raged on, no effort was spared to develop combat-ready microwave radar equipment that eventually gave the Allies a decisive edge in World War II. The remarkable success of this wartime effort depended not only on the goodwill between the U.S. and Britain, but also on an innovative partnership that was taking shape between academia, industry and the government, and the new cooperation that was evolving between physicists, engineers, and other scientists from different academic backgrounds. These fledgling bonds would transform scientific research and how it would be carried out in the future.

Hands Across the Water

Radar, an acronym for radio detection and ranging, had been patented in 1935 by British scientist Sir Robert Watson-Watt for meteorological applications. Watson-Watt and other scientists believed that radar could also be developed into a system to locate objects using transmitted and reflected high-frequency radio waves. The range of an object in the radio wave’s path could be determined by measuring the time it took to transmit and receive the reflected radio waves. This idea had potential for navigation and military applications, especially in determining the distance and altitude of airborne objects.

During the 1920s and '30s, early radar research was being conducted by Germany, France, the United States, and Britain. By the late '30s, the Chain Home network, a ground-based radar network along Britain’s east and south coasts, was in operation. Chain Home was a system of antennas that could detect aircraft up to 150 miles away and low-flying planes as they came over the water. Because it removed the element of surprise, the system was crucial during the London Blitz. British fighter planes were also using radar at one-meter wavelength frequencies. But, in 1940, microwave airborne radar was not yet realized.

From left: Professors Julius A. Stratton, Albert G. Hill, and Jerome B. Wiesner have been the inspiring and foresighted builders of the Research Laboratory of Electronics As both RadLab scientists and RLE directors, all three have emphasized the importance of collaboration between government, industry, and academia in broad-based, fundamental research. (1948 Photo by Benjamin Diver)

With Germany threatening, invasion, British scientists aggressively experimented with shorter wavelengths, narrower beams, more compact equipment, and greater power generation to improve their radar capability. Existing radar operated on relatively low frequencies with wavelengths several meters long. The goal was to generate more powerful and narrower beams that operated on shorter wavelengths which could more accurately pinpoint small, airborne targets. The problem was generating enough high power at these shorter (microwave) wavelengths.

In August 1940, the British government dispatched the top-secret Tizard Mission to the United States to exchange information on radar. The mission's members were Sir Henry Tizard, Chairman of the British Aeronautic Research Committee; Sir John Cockcroft, Director of the British Army Air Defense Research and Development Establishment; and Dr. Edward G. "Taffy" Bowen, a cosmic ray researcher from the University of London. The Tizard Mission arrived first in Canada, and then traveled on to Washington, DC, to meet with the U.S. National Defense Research Committee (NDRC).

The NDRC had been conceived by Dr. Vannevar Bush, Dean of Engineering at MIT and scientific advisor to President Franklin Roosevelt; Dr. James Conant, President of Harvard University; and Dr. Karl Taylor Compton, President of MIT. Established in June 1940 as an independent federal agency under Vannevar Bush, the NDRC sought to apply civilian scientific ideas in military operations. NDRC's Section D-1, known as the Microwave Committee, consisted of representatives from industry and was charged with investigating radio detection and countermeasures. Dr. Alfred L. Loomis, lawyer-scientist and MIT Corporation member, headed up the Microwave Committee. (Dr. Loomis also hosted a program for MIT students at his Tuxedo Park, New York, laboratory on microwave radiation and the detection of moving targets using the Doppler effect.)

In September 1940, the Tizard Mission met with representatives from the U.S. Navy and Army, the NDRC, and its Microwave Committee to exchange highly sensitive information on radar. The U.S. Naval Research Laboratory disclosed that it had obtained clear, pulsed echoes from aircraft and from those sprouted the idea for the MIT Radiation Laboratory.

Off to a Fast Start

Initially, Bell Telephone Laboratories’ findings had produced shipboard radar. The U.S. Signal Corps had also devised mobile air-warning radar and searchlight-director radar. But, neither country had made substantial progress in airborne radar or high-power transmitters for centimeter wavelengths. In a pivotal meeting with the Microwave Committee, the Tizard Mission revealed the 10-centimeter resonant cavity magnetron invented by British physicists Dr. H.A. Boot and Sir John T. Randall at the University of Birmingham. This magnetron, an efficient, high-power (10-kilowatt) pulsed oscillator that operated at 10-centimeter wavelengths, proved to be the seed that General Electric, Westinghouse, Sperry, and RCA agreed to quickly supply the magnetrons and other components needed. The NDRC, its Microwave Committee, and the Tizard Mission worked out plans for an independent laboratory that would be staffed by civilian and academic scientists from every discipline. Lee A. DuBridge, a nuclear physicist from the University of Rochester, was hired as the laboratory’s director on October 16, 1940. On the following day, MIT was chosen as the site for this still unnamed laboratory. Later that month, under the guise of an applied nuclear physics conference at MIT, staff members were recruited. Kenneth T. Bainbridge (SB'25, SM'26), a Harvard physicist, was the first to be enlisted, and the laboratory's first meeting took place on Armistice Day 1940 in MIT's Building 4 Room 133. Finally, a name was chosen. To protect the secrecy of its sensitive work, it was called the Radiation Laboratory. The name conjured thoughts of atomic and nuclear physics, a safe and acceptable field of scientific investigation at that time. It also served as a decoy for the laboratory's real work on sophisticated microwave radar.

Fourteen months before the U.S. entered World War II, RadLab (as it was known) began its investigation of microwave electronics. Six technical working groups were set up to study different components: pulse modulators, transmitter tubes, antennas, receivers, cathode-ray tubes, and klystrons. The first three projects tackled by RadLab were Britain's top priorities:

Project 1 focused on 10-centimeter airbome intercept microwave radar that could be used by bombers to detect enemy aircraft at night. The first success of Project I came in February 1941, with the detection of buildings in Boston across the Charles River from a two-parabola system on MIT's Building 6. But, as night bombings of London decreased, attention turned to anti-submarine strategies, since German U-boats threatened to cut Britain off from the sea. The experimental airborne intercept project then shifted to aircraft-to-surface vessel detection. Project 1 also spawned experiments in shipborne search and landbased harbor defense systems.

Project II, which developed 10-centimeter ground radar for anti-aircraft gun-laying, began in January 1941. The goal was to produce automatic radar tracking to control the aiming and firing at enemy aircraft. Project II resulted in the production of the highly successful SCR-584 gun-laying radar, which is credited with destroying 85% of the V-1 buzz bombs that were dropped on London.

Project III involved long-range radio navigation for ships and aircraft called LORAN. LORAN enabled crafts to locate themselves using radio frequencies. It improved on Britain's Oboe system for bombing Europe and also guided North Atlantic convoys later in the war. By the end of the war, LORAN covered one-third of the Earth's surface.

On October 9, 1990, IEEE President Eric E. Sumner (left) presorted an Electrical Engineering Milestone commemorative plaque to MIT President Paul E. Gray. The plaque, installed in the corridor outside of MIT room 4-133, RadLab's original office, reads. "The MIT Radiation Laboratory, operated on this site between 1940 and 1945, advanced the Allied war effort by making fundamental contributions to the design and deployment of microwave radar - the first radar system small enough to be operated in aircraft. In the process, the Laboratory’s 3900 employees made lasting technological contributions to microwave theory, operational radar, systems engineering, long-range navigation, and control equipment." IEEE established the Milestones program in 1983 to honor accomplishments in electrical and electronics technology. Through this program, the IEEE hopes to increase the understanding of electrical history, among engineers and the public, and to encourage preservation of the historical record of these achievements. The Milestones program is sponsored by the IEEE History, Committee and administered by the Center for the History of Electrical Engineering at Rutgers University. (Photo by John F. Cook)

The resonant cavity magnetron has been described as a "metal ball with protruding glass horns. British physicist Sir Jobn T. Randall and Dr. H.A Boot, working under Professor M.L. Olipbant at the University of Birmingham, deteloped the idea of using the klystron's resonant cavity principle in a magnetron. Several production models of this magnetron were manufactured (with different numbers of cavities) by British GEC in 1940, and one accompanied the top-secret Tizard Mission to the United States. Thought to have been a six-cavity magnetron, the mission accidentally brought one with eight cavities for demonstration. Thus, British models have six resonant cavities, and American models have eight. In this electronic tube, electrons are generated from a heated cathode and move under the combined force of a radial electric field and an axial magnetic field to produce high-energy microwave radiation in the frequency range from 1-40 gigahertz. The miagnetrons used for radar applications generate pulsed energy while magnetrons for microwave ovens generate continuous radiation. (Photos courtesy MIT Museum)

The Proving Ground

U.S. government and military officials were skeptical of both the civilian scientists and the experimental radar technology. But, on the morning of the Pearl Harbor attack, an Army ground-based long-wavelength radar set at Opana, Oahu, detected Japanese planes as they approached the island. Even though the radar's indications were reported to the officers in command, it was mistakenly believed that the equipment was malfunctioning, and the warnings went unheeded. Consequently, radar gradually gained acceptance as the equipment designed at RadLab proved its accuracy on the battlefields of Europe, Africa, and the Pacific.

In April 1942, Professor Edward L. Bowles was selected as a consultant to Secretary of War Henry Stimson. His first assignment was to assess radar's role in detecting German submarines. Since U-boats would surface at night to attack convoys, they could not be located by sonar defenses. Professor Bowles persuaded the military to use radar in defense of the Atlantic. Radar was installed on escort ships and, working in tandem with sonar, enabled the Allies to track the U-boats above and below the surface. This proved crucial in winning the Battle of the North Atlantic.

The RadLab was not alone in its mission. Other electronic research centers under NDRC sponsorship studied radar and microwaves. Harvard University's Radiation Research Laboratory worked on countermeasure methods and other aspects of electronic warfare. Columbia University's Radiation Laboratory was established in 1942 and headed by RadLab scientist Isidor I. Rabi. Columbia's Rad Lab investigated microwave components such as the tunable X-Band magnetron that operated at frequency ranges above existing devices. Brooklyn Polytechnic Institute's Microwave Research Group worked on measurement techniques and components for microwave systems.

RadLab also contracted with seventy industrial companies to assist in mass producing radar sets. These companies included General Electric, Raytheon, RCA, Westinghouse, Philco, Sperry, and Western Electric. In October 1941, RadLab established its own company, the Research Construction Company (RCC), to manufacture limited quantities of microwave radar systems and components that were not immediately available from industry.

Fire control, airborne radar for blind and precision bombing, ground imaging, beacon bombing radar, bombing reconnaissance, mobile microwave sets, aircraft and ship search radar, and harbor/coastal surveillance-these are only a few of RadLab's other projects. The microwave early warning system had the greatest range and adaptability of all the microwave ground equipment produced at RadLab, and it played a leading role in D-Day operations, as did the SCR-584 fire-control radar. Supporting the laboratory's hardware production was a group devoted to advanced research on microwave propagation and transmission; the theory of noise, antennas, and waveguides; and signal and design problems with the radar systems. This group was headed up by Isidor I. Rabi, who has been acknowledged by many as RadLab's "scientific heart and soul."

What began as a British-American effort to make microwave radar work, swiftly evolved into a centralized laboratory, committed to understanding the theories behind experimental radar while solving its engineering problems. From 1940-1945, RadLab designed almost half of the radar deployed in World War II, created over 100 different radar systems, and produced $1.5 billion of radar equipment. By the end of the war, over a million magnetrons had been produced by the Allies, some operated at millimeter wavelengths, and others were capable of one-megawatt of power.

RadLab occupied fifteen acres of MIT space, and its field stations included East Boston (Logan) Airport and Deer Island; Orlando, Florida; and Spraycliff, Rhode island. Branches also sprung up on several continents, including the British Branch of the Radiation Laboratory at Malvern, England, and the Advanced Service Base in Paris, France. The RadLab switchboard soon became the largest in Cambridge. Almost 4,000 men and women worked for RadLab-nuclear physicists, chemists, mechanical and electrical engineers, mathematicians, biologists, bankers, lawyers, accountants, secretaries, professors, and students. Nine staff members went on to become Nobel laureates, and two became presidential science advisors.

MIT's research program at the 277-acre Round Hill estate in South Dartmouth, Massachusetts, started in 1923. Colonel Edward Howland Robinson Green offered the use of his property to MIT where radio station WMAF broadcasted early network-like programming. Experiments at Round Hill focused on radio communications, the theory, and application of microwaves, air navigation, and radio and light propagation through fog This program was the forerunner of research that was to take place in the MIT Radiation laboratory In 1936, the property, was given to MIT following Colonel Green's death, and various experiments were carried out there by MIT and Lincoln Laboratory, until the estate was sold in 1964. (Photo courtesy MIT Museum)

A Picture of War

"June 5 was a clear beautiful night. It was a bit windy a little after midnight; the moon was up bright and nearly full. The sea was much calmer than previously. After the operation had started it really was a night to set your blood tingling.

"At 2345 something new appeared on the scope; a kind of target I had never seen before. It was a long streak moving directly south. A second group appeared at 2355 looking almost the same; and at 2356 the first streak turned straight east. I had no longer any doubt that something big was on. At 0010 Squadron Leader Cherry Downes told us the Invasion had started, that we were taking part in it and had to do our job as well as possible."

In this way, as reported by the Laboratory’s E.C. Pollard, the invasion of France began. Pollard sat in England at a MEW (microwave early warning radar) scope and watched it. He saw armies of planes arise, form and head down towards France. Strings of planes, 20, 40, and 80 miles long were visible at once. Weaving in and out among these, each one separate and distinct, were the roving fighter planes that furnished cover. This whole air fleet performed a slow orbital movement, swinging down over France, dropping the bombs, swinging up over England again and dispersing. It went on all night and continued the next day. It was a picture of war no man had ever seen before....

Reprinted from Five Years at the Radiation Laboratory.

RadLab Ends with a New Beginning

Termination of RadLab was announced on August 14, 1945, and it formally closed on December 31, 1945, leaving behind tons of surplus equipment and a concept for basic research that was to continue in MIT's Research Laboratory of Electronics. The laboratory's technical achievements were recorded in a 28-volume set, the Radiation Laboratory Series, published in 1948 by McGraw-Hill, which is still used today by engineers as a definitive reference on microwave theory and techniques.

Plans for a peacetime continuation of RadLab had been under consideration since the invasion of Normandy in June 1944. Professor John C. Slater conceived the idea for an electronics laboratory at MIT that would operate jointly under the Department of Physics and the Department of Electrical Engineering. In August 1944, Slater met with MIT President Karl T. Compton, Dean of Science George P. Harrison, and Professors Harold L. Hazen and Julius A. Stratton to discuss these plans. Slater recommended Stratton as director, and in September 1945, Stratton presented a transition plan for the new laboratory. The NRDC had already voted to provide continued funding under the RadLab contract.

On January 1, 1946, a fragment of RadLab was set up as a transitional organization called the Basic Research Division. Under Director Julius A. Stratton and Associate Director Albert G. Hill, it continued investigation on problems in physical electronics that involved cathodes, electronic emission, and gaseous conduction. In microwave physics, the electromagnetic properties of manner at microwave frequencies were studied, and modem techniques were applied to both physics and engineering research. Engineering applications were used in microwave communication studies.

In March 1946, the Department of Defense set up a committee to oversee the transition: Lieutenant Colonel Harold A. Zahl (Army), Commander Emanuel R. Piore (Navy), and Major John W. Marchetti (Air Force). These three were later joined by Mr. John Keto (Army Air Corps) on a technical advisory committee for what was to become the Joint Services Electronics Program (see related article, page 7).

On July 1, 1946, the Basic Research Division was finally incorporated into the new Research Laboratory of Electronics (RLE) at MIT.

RadLab's Microwave Legacy

A plan position indicator scope image of Cape Cod (left), as seen with the experimental airborne search and bombing radar known as X-band AS developed at RadLab. From this 1942 picture, the exact shape of Cape Cod was known for the first time (compare to"map on right). Radar photos such as this one prompted a surprised British RAF dignitary to say, "Gentlemen, this is a turning point in the war. " (Photo courtesy MIT Museum)

The growth of RLE research was boosted by the abundance of microwave components and test equipment left over from the RadLab. Professor George G. Harvey has been credited with inventorying and tagging much of RadLab's surplus equipment, thus ensuring its continued use at RLE. This valuable equipment was coupled with the newly acquired knowledge of microwave measurement techniques plus the backlog of many uninvestigated theoretical and experimental ideas from World War II. RLE scientists and students could now capitalize on shared academic interests, the lab's pooled physical resources, and a new common funding source in the Joint Services Electronics Program.

In 1946, there were five RLE research groups: microwave and physical electronics, microwave physics, communications and related projects, modern electronic techniques applied to physics and engineering, and aids to computation. The microwave studies focused on the generation of powerful radar transmitter pulses, while the activity, in electronic circuits and aids to computation supported work in theoretical design and statistical communication.

Both the microwave and communication interests branched out in many different directions over the years:

Microwave spectroscopy: Professor Malcom W.P. Strandberg studied fundamental atomic resonance phenomena that contributed to the basic knowledge of quantum-mechanical amplifiers. This ultimately led to the invention of devices that could generate coherent radiation by stimulated emission of radiation (the maser and laser).

Research on atomic and molecular beams was another direction that resulted from RLE's initial interest in physical electronics. Professor Jerrold R. Zacharias investigated the resonance phenomena associated with nuclear magnetic moments of elements such as cesium. This work contributed to the first practical demonstration of atomic clocks. Highly accurate standards for time measurement were established using the frequency characteristic of certain atoms, such as cesium, as they were observed in a molecular beam apparatus. The cesium frequency standard is now used commercially and is important in scientific observations and in terrestrial and space navigation systems.

The interest in physical electronics also branched off into solid-state physics, which addressed fundamental problems in condensed matter physics and electronic materials and structures.

Plasma dynamics. Absorption properties of ionized gases in microwave gas discharge experiments conducted by Professor Sanborn C. Brown verified the theory work of Professor William P. Allis and stimulated plasma dynamics research in RLE. There was a special emphasis on radio frequency and microwave gas discharge breakdown and spectroscopy. Initially, the experiments were concerned with low-temperature, low-density plasmas, and progressed to high-temperature, high-density, and hilly ionized plasmas. Studies of plasma resonance phenomena led to a better understanding of high-frequency radio wave transmission, since the upper atmosphere contains layers of ionized gas. Later, there were plasma radiation studies and the first quantitative measurements of cyclotron emission and bremsstrahlung by Professor George Bekefi. The phenomena of wave instabilities were also explored, which led to their first classification. In the '60s and '70s, the generation of coherent electromagnetic radiation and the development of new microwave and millimeter-wave devices also came from this work and ultimately resulted in the building of free-electron lasers. Professor Bruno Coppi later examined the magnetohydrodynamics of hot fusion plasmas and advanced the theory for the highfield tokamak. In 1980, the evolution of plasma research at RLE contributed to the formation of MIT's Plasma Fusion Center.

Linear accelerator and magnetron phasing. The problem of magnetron phasing was addressed by Professor John C. Slater's construction of a small linear accelerator for electrons. The knowledge acquired in RadLab was the basis for his work, and additional techniques were conceived in RLE. Klystrons or other microwave power sources eventually replaced the magnetron in more modern accelerators, but this work was important in perfecting this type, of particle accelerator. In similar studies more closely related to communication and radar applications, Professor Jerome B. Wiesner and graduate student Edward E. David, Jr., (both future Presidential science advisors) investigated transient and steady-state phenomena in phase-locking a magnetron to a more stable source.

Phase-sensitive microwave systems. Missile guidance studies in the late '40s and early '50s included Project Meteor, the code name for a ship-to-air missile research program. Professors Lan Jen Chu, Henry J. Zimmermann, and Campbell L. Searle developed fundamental phase-sensitive microwave systems used in missile guidance. Professor Chu's microwave interferometer used for Project Meteor's homing device led to other studies in phased-array radar systems. Microwave interferometer, was also employed in radio astronomy, where very-long baseline interferometers (VLBI) obtain high angular resolution of distant sources. Professors Bernard F. Burke and Alan H. Barrett have used VLBI to correlate radio signals in stellar maser observations. This work received the 1971 Rumford Prize of the American Academy of Arts and Sciences.

Radio astronomy instrumentation

RadLab's interest in minimizing component and cosmic radio noise stimulated RLE studies of high-performance amplifiers. Many early radio astronomy studies were done with former radar equipment (the dishes used to track targets were now tracking celestial objects with great accuracy), but a variety of new instruments were created as the science evolved. In RLE, Professor Alan H. Barrett used balloon-borne radiometers to measure the oxygen concentration in the atmosphere (OH line), and made microwave observations of Venus in 1962 using radiometers on a NASA Mariner spacecraft. That same year, Professor Louis D. Smullin and Dr. Giorgio Fiocco were the first to bounce a laser beam off the moon's surface.

Optics. Interest in characterizing noise in electronic amplifiers led to the study of optical systems. Although the noise properties of high-speed optical systems are not practical for analog communications, the ability to produce ultrashort optical pulses is important for digital optical communications. Today in RLE, Professors Hermann A. Haus, Erich P. Ippen, and James G. Fujimoto study femtosecond optical phenomena in a variety of materials and exploit this understanding for high-speed optical switching.

Communication sciences. Statistical communication theory and information and coding theory focused on problems in the generation, transmission, and processing of signals. Studies in statistical communication theory (by Professors Norbert Wiener, Yuk Wing Lee, and Jerome B. Wiesner) gave a better understanding of the communication process in the presence of noise and interference, the optimization of system parameters, and new forms of communication systems. Information theory and coding theory (Professors Claude Shannon, Robert Fano, David Huffman, Peter Elias, Robert Gallager, and John Wozencraft) involved quantitative studies of different noisy channels in terms of the rate of information transmitted. The work was initially concerned with channel capacity, and methods were used that approached the theoretical limit on transmission rate. But, as digital data transmission became more important, the emphasis shifted to error rate and the methods to reduce it by, means of error-correcting codes.

The pulsed techniques devised in RadLab were classified information, but in later years they would prove useful in communication technology that used pulses to convey messages. Professor Ernst Guillemin and Dr. Manuel Cerrillo worked on time-domain network synthesis which led to discrete systems and then to pulse techniques in computers. Guillemin and Cerrillo also worked on electronic circuit theory and the basis for circuit synthesis with graduate student John Linvill, who wrote an important thesis on the gain-bandwidth characteristics of amplifiers.

The results from the research projects mentioned above also stimulated MIT's academic program, where new subjects have been introduced in physics, electrical engineering, and other disciplines. Many of these new subjects began as graduate seminars in RLE while the research was in progress.

Riding the Beam from GCA to MLS

Since World War II, radar has been adapted for many purposes, including the navigation of civil aircraft. Highly accurate tracking guidance systems and distance measuring equipment have been used for air traffic control en route or in the airport control area. These systems are especially helpful in bad weather and under heavy traffic conditions.

Early blind-landing systems were studied at MIT's Round Hill program. The RadLab also produced a system for landing airplanes called ground control of approach (GCA). Since most of the GCA equipment was ground-based, the pilot received verbal landing instructions via radio communication. The plane would be detected at a range of 15-20 miles with 10-centimeter search radar, brought on course for landing, and guided down a glide path by the approach controller with a high-precision 3-centimeter system. The first GCA used in combat was at a night-fighter field near Verdun, and was credited with forty landings.

GCA was only one of several airplane navigation systems that was created during the war. Another, the instrument Landing System (ILS), is still used today as a low-approach guidance system to aid pilots in poor visibility. Although ILS is currently the worldwide standard precision approach guidance system, it has several drawbacks: there must be flat terrain over an extended area for accurate ground reflection patterns, flight patterns must be restricted to a single straight approach path, and there are communication problems with multipath interference. ILS is now over-burdened as large metropolitan areas are faced with airport congestion and channel spacing problems.

Professor Jin Au Kong's group in RLE's Electromagnetic Theory and Applications Group is investigating possible improvements using a different system, the Microwave Landing System (MLS). MLS offers several advantages over ILS: flat terrain is not required; shorter, curved flight approaches are permitted that can save fuel and reduce noise; and its channel capacity is five times larger than ILS. Professor Kong's group uses a computer simulation tool called EMSALS (Electromagnetic Simulations Applied to Landing Systems) to model and analyze the frequency, congestion and electromagnetic interference problems from ten metropolitan U.S. areas. Further details of this research can be found in RLE Progress Report No. 133.

Professor Jin Au Kong and his students and colleagues in RLE's Center for Electromagnetic Theory and Applications are evaluating a new airport traffic control system, the Microwave Landing System. Professor Kong displays a model of what may someday be the design for airplanes capable of vertical take-offs and Landings using the new, landing system. (Photo by John F Cook)

RadLab Readings

No single book or document has ever been published on RadLab's history, but several sources include it as part of a larger work:

A Century of Electrical Engineering and Computer Science at MIT, 1882-1982, by Karl L. Wildes and Nilo A- Lindgren, touches on the lives of the many individual who were part of RadLab and discusses historically important technological advances within MIT's Department of Electrical Engineering and Computer Science and RLE. (MIT Press, 1985)

Radar Days, by Edward G. Bowen, is an insightful personal history from Dr. Bowen's early involvement in the scientific discoveries of wartime radar in England through the inception and creation of radial. Dr. Bowen was a member of the Tizard Mission and RadLab. (Adam Hilger, 1987)

The MIT Radiation Laboratory Series, edited by Louis N. Ridenour, is an extensive technical documentation of RadLab projects in 28 volumes with an index. The series is now out of print, but is available at many scientific reference libraries including the RLE Document Room.

Five Years at the Radiation Laboratory was published by MIT after the termination of RadLab. This book is the most comprehensive overview of the laboratory, its work, and the people who were part of this unique experience. Originally published with classified information omitted, a limited number of copies has now been reprinted by the Boston chapter of the IEEE Microwave Committee to commemorate the RadLab's 50th anniversary, with much of the restricted information reinstated.

Echoes of War is part of the NOVA television series on the Public Broadcasting System. This one-hour program, which was produced in 1989, surveys RadLab's role and the impact of radar in World War 11, and includes interviews with several RadLab members. Videotapes of the program are available through the WGBH Public Video Service by calling (800) 248-8311. Transcripts are also available through NOVA Transcripts, Journal Graphics, 267 Broadway, New York, NY 10007.

by Dorothy A. Fleischer

A Building with Soul

A World War II survivor, Building 20 as it looks today, with the Research Laboratory of Electronics (Building 36) in the background.

"Building 20 is an admixture of all the interesting things at MIT," says Lettvin, a jovial mountain of shivering cerebra who is admired inside Building 20 not for his genius but as a man who first uttered a profanity on television, during a 1961 debate with Timothy Leary ("It made the front page of Variety," Lettvin insists. "You can look it up.")

What's so special about Building 20? Even the MIT Museum had trouble answering that question in 1980, when it organized an exhibit dedicated to the ramshackle "Plywood Palace," the least descript of all the institute's studiously nondescript structures. "Why do we celebrate a building so modest, so meek and indeed so homely in its demeanor?" asked the introduction to the exhibit catalogue.

First off, we celebrate its history. One of several temporary structures thrown up on campus during World War II -- it took less than an afternoon to design -- Building 20 is the only one still standing. Many of MIT's greatest projects, including the wartime radar project and its first interdisciplinary labs started in Building 20, along with many of the institute's leading professors.

Secondly, the building is the kind of academic melting pot that gives university presidents indigestion. Famed linguist and antiwar activist Noam Chomsky works just a few doors away from MIT's ROTC offices, which have decorated one whole wall with a colorful mural of an F-16 fighter.

The music department's piano repair facility -- a "computer-free zone," according to a sign on the

wall--shares a floor with the nuclear science lab's shop room. The model railroad club, which houses the most sophisticated toy train in the world, is just a stone’s throw away from the chemical engineering department's cell culture lab, where a bulletin board message inquires plaintively: "Did anybody use toxic substances in the small Corning spinner flasks? About half of mv cultures died without apparent reason."

After the war many of the heavyweight research projects moved into their own buildings, and Building 20, with its creaky floors and poor ventilation, attracted researchers who couldn't find space elsewhere at MIT. Once they settled in, they fell in love with the place. "It turned out to be absolutely perfect for research," explains Halle, an ebullient bearded scholar who has made Building 20 his home for 37 years. "You can knock down a wall, you can punch out a ceiling, and you could get space. In academics, space is everything."

In the interests of space, Halle's lab launched an "expansionist" raid against the model railroad club's huge two-room suite. The land grab failed because the club argued that its computerized, 200-switch track layout could not be easily moved. Indeed, a move against the club might have set off a revolt among the building's older tenants, who fondly remember the five-cent Cokes dispensed from the club's specially programmed soft drink machine.

Not suprisingly, Building 20 has its own myths.

"I know someone who can tell you some hair-raising stories about the early days of microwave," Lettvin says, shoving aside piles of unopened mail to dial his phone. Unfortunately, his contact isn't in.

"Remember the phantom?" Lettvin asks. Indeed, Halle does remember the mysterious, homeless botanist who camped out in a Building 20 storeroom and haunted the building's corridors during the ‘60s and '70s. No one knows how he supported himself, or who his family was. "He turned down a job at the Field Museum in Chicago in order to remain a phantom in Building 20," Lettvin says.

The professors say MIT tried to evict the squatter and lost their case in a Cambridge court. The phantom hung on until 1980, only to drift into oblivion--and into the history of Building 20.

"A Building with Soul" by Alex Beam originally appeared in The Boston Globe, June 29, 1988. It is reprinted with permission of the Boston Globe.

Please Be Seated

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Today, Professor Abraham Bers (left) and Professor Emeritus Louis D. Smullin enjoy, a moment in the DuBridge chair as shown in the photograph below shows imprinted tag still in place. (Photos by John F. Cook)

When MIT Building 22, previously occupied by the RadLab, was razed in 1954, several stray chairs from the RadLab's conference room found a home in Building 20. Graduate student Abraham Bers had just arrived at MIT and was assigned to room 2OB-003, which he shared with the chairs. These wood desk chairs were typical of the World War II period, and were probably considered executive" models since they, had arms. Two chairs displayed name tags stamped with "L.A- DuBridge," MIT's Radiation Laboratory director. Prof. Bers, who was to join the faculty of the Department of Electrical Engineering and Computer Science in 1959, learned the historical significance of that name and has taken care of the chairs ever since. One might say that Professor Bers is the "holder of the DuBridge chairs."

The chairs have since moved several times with Professor Bers, who is a principal investigator in RLE's Plasma Physics Group. they, are now in the library across from his office in Building 38. "I'm not the only one who received support from these chairs," admits Professor Bers with a smile, referring to the many students he has worked with over the years. "They all sat a lot when they were here."

For now, the chairs will remain in his library. In the future, perhaps someone will offer to care for them as Professor Bers has done. Or, the chairs might find a home at the Smithsonian, because, in hindsight, didn't radar put an end to flying by the seat of one's pants?

Director's Message

Professor Jonathan Allen, Director, Research Laboratory of Electronics

The fiftieth anniversary of the founding of the MIT Radiation Laboratory (RadLab) is being celebrated this year, and we are especially pleased to devote this issue of currents to a remembrance of that lab, its many accomplishments, and its strong leadership. RLE is the natural continuation. into peacetime of the RadLab style. The extensive array of equipment amassed in the RadLab formed our initial equipment inventory, and our first three directors were associated with the RadLab.

The wartime experience in the RadLab showed that talented people from several disciplines could effectively focus on a variety of fundamental and applied research projects with outstanding results. Many of these investigators acquired new skills in order to solve these problems, and their achievements showed how effective interdisciplinary research can be.

This was the heritage upon which RLE was designed and founded, and the wide variety of research presently found in RLE is ample testimony that the interdisciplinary style of research started in the RadLab continues vigorously. We are extremely proud of our roots, and look forward to extending the RadLab style into the exciting future.