For many professors, it would be legacy enough to have sent so many students into the hallowed halls of academia and the boardrooms of Silicon Valley. But for Meindl, it's just part of the story. He also did pathbreaking research in the design of low-power circuits and in the interconnects that link blocks of logic in a chip. It was for those achievements—specifically, his ”pioneering contributions to microelectronics, including low-power, biomedical, physical limits, and on-chip interconnect networks”—that he was awarded this year's IEEE Medal of Honor.
And yet, when Meindl started out in technology, half a century ago, semiconductors were little more than laboratory curiosities. Enrolling in 1951 at Carnegie Institute of Technology (now Carnegie Mellon University), in Pittsburgh, he planned to get a degree in power engineering and then design heavy electrical equipment at Westinghouse Electric Corp., where his father worked. But in 1955, Carnegie's graduate power engineering department abruptly vanished: one professor quit and another changed fields.
Meindl, then just starting graduate school, was open to suggestions about what to do next, and Professor Edward Schatz had one. The U.S. military was trying to improve its communications systems and needed an energetic graduate student to analyze the loss of radio-frequency signals transmitted through coaxial cables. The goal was to come up with equations that would describe the signal loss and allow engineers to build better cables. Meindl solved the problem in 24 months, in the process becoming quite well versed in Maxwell's equations, the set of four equations describing the behavior of electric and magnetic fields and their relationships to each other and to electric-charge and electric-current density. Facility with these equations, which are considered to be the foundation of electrical engineering, gave Meindl the insights he needed to understand that latest electronic marvel, the semiconductor.
Meindl got his Ph.D. in electrical engineering in 1958. He took a job at Westinghouse, as he'd planned all along, but not as a power engineer. Instead, he became one of the company's first semiconductor engineers. His initial assignment was to use silicon-controlled rectifiers—diodes that must be triggered by a voltage pulse in order to conduct current—as part of an electronic system that would manage the control rods of a nuclear reactor. He loved the job. ”I got to buy and burn out transistors that cost about a thousand dollars each,” he recalls. ”And I learned that electrical engineering can be a lot of fun.”
Unfortunately, the fun only lasted about a year. In 1959 he received a summons from the U.S. Army. It was payback time. Meindl, a member of the Reserve Officers' Training Corps program during college, went on active duty.
”Here I was, working,” he recalls. ”I had a great job, I had bought my first new car, and I just felt that the world is a really good place. And suddenly, here comes Uncle Sam.”
He ended up at the U.S. Army Signal Research and Development Laboratories, in Fort Monmouth, N.J. [see photos, ” One Haircut, Three Decades”]. It turned out to be ”the most fortunate unwanted experience” of his life. For one thing, he met his future wife, Frederica. She was an administrative assistant for Meindl's supervising officer. They had their first date that October, and the rest, Meindl says, is history.
Encountering his life partner wasn't the only happy surprise at Fort Monmouth. There was also his work assignment, which turned out to be a lot more interesting than he was expecting: he worked with integrated circuits—a field then barely six months old.
Just after Meindl arrived at the R&D labs, the Army awarded a research contract to Dallas-based Texas Instruments Inc., where Jack Kilby had built one of the first ICs. Meindl became the technical liaison for the project. He met Kilby in November; a few months later, early in 1959, he visited Gordon Moore and Robert Noyce at Fairchild Semiconductor Corp., in Palo Alto, Calif. Those three pioneers taught Meindl about the nascent field, and he began his own research, trying to figure out how to make an IC operate at a power level so low that it could be used inside a helmet as part of a radio receiver. Meindl stayed at Fort Monmouth for eight years, two as an Army officer and six more as a civilian.
In the early 1960s, hardly any engineers outside the military were interested in minimizing the power used by electronics. Metal-oxide semiconductors (MOSs), which consumed significantly less power than their bipolar predecessors, were in their infancy and had stability problems. But as the decade went on, the growing popularity of the quartz watch and the in-ear hearing aid, both of which could accommodate only tiny batteries, brought attention to the need for low-power circuits. Still, when Meindl published his first and only book, Micropower Circuits (Wiley), in 1969, you could count the number of copies sold on two hands.
But Meindl was onto something. ”Even at a time when few people worried about power consumption, he thought it was an interesting area to explore, because it would eventually become a big issue,” Plummer says. And so it has: laptop computers, cellphones, and iPods illustrate that product design today is all about reducing power consumption and extending battery life.
By 1966, several professors at Stanford were encouraging Meindl to leave New Jersey and join them in California. In 1967, John Linvill, then chair of the electrical engineering department at Stanford, made Meindl an offer he couldn't refuse. Linvill had come up with an idea for a system that would let blind people—including Linvill's own young daughter, Candace—read. It would use a camera to take a picture of the letters on a page and then translate that picture to a tiny pad of vibrating pins. With training, Linvill reasoned, a blind person would be able to place a finger on the pad and decipher the text. But making such a device portable and useful required two custom-designed, low-power chips. One chip would act as the image sensor—a solid-state camera, basically, at a time when they were experimental. The other chip would operate at a high voltage to vibrate the tactile array, consuming as little power as possible to prolong battery life.
Meindl worked on the project for about a year, along with several graduate students, including Plummer.
”We had significant problems,” Plummer recalls. They were using MOS devices in a high-voltage application—which no one had done before. After a lot of trial and error with the voltage levels, they finally found one that was high enough for the vibration to be felt by the user and yet low enough to keep the devices from burning out.
The group dubbed the device the Optacon, for optical-to-tactile converter, and demonstrated it for the first time at the 1969 International Solid-State Circuits Conference, in Philadelphia. Linvill's daughter Candace demonstrated the converter, and she got a standing ovation. ”That,” Meindl says, ”was the most thrilling moment in engineering work that I have ever had.” He later named his own daughter Candace to honor Linvill's daughter and the moment.
In 1970 Linvill, Meindl, and their team rolled the technology out into a company, Telesensory Systems Inc., now a division of the Singapore company Insiphil. Telesensory produced tens of thousands of the devices and sold them around the world. Today, text-to-speech converters have supplanted the Optacon, but it was an important aid in its time.
Telesensory never made its founders a fortune, but that didn't bother Meindl. Throughout his career, he says, he and his co-workers have always selected ”areas that could have the most impact.”
Inspired by that moment at the 1969 conference, Meindl asked a group of his Stanford students to develop novel low-power sensors and circuits for use in medical research. Gerzberg, who was part of the group, recalls that challenges were everywhere: in signal-processing algorithms, in circuit design, in chip fabrication, in systems integration, and in coordinating with medical researchers. Gerzberg also remembers that Meindl's enthusiasm never wavered. Gerzberg says, ”Once I gave him a demo of a prototype I had built, the first time I had it working, and he actually stood up and clapped his hands for several minutes. He always made me feel so good.”
The students built sensor packages that could be implanted in research animals, transmitting physiological data while the animal went about its normal activities. A medical researcher inserted one such sensor package in a monkey fetus still in the mother's uterus. The monkey mother eventually went into natural labor; the researcher then wirelessly activated the sensor package to provide the first detailed information about the baby's physiological experience during birth. Meindl and several graduate students designed another device to measure the velocity of blood cells as they flowed through different parts of the body. Meindl attended a procedure in which a surgeon used this device to monitor the progress of a heart valve replacement; after the artificial valve had been sewn into place, the flowmeter flagged a problem with the new valve, and the surgeon quickly replaced it, possibly saving the patient's life.
Another achievement at Stanford hasn't saved any lives, but it has saved many designers countless hours of R&D time. In 1971, Meindl posed a simple question to graduate student Swanson: theoretically, what is the lowest possible voltage at which an arbitrary complementary metal-oxide semiconductor (CMOS) circuit could operate? Knowing this value would prevent circuit designers from exploring dead ends—techniques that would drive the voltage so low the designs wouldn't work. Swanson determined that the minimum voltage is a multiple of the thermal energy of the material, with that multiple changing in a predictable way depending on the temperature of the material. Circuit designers the world over still use that fundamental limit.