Mahta Moghaddam: Harvesting Electromagnetic Waves

With the goal of harnessing the untapped potential of Iranian-Americans, and to build the capacity of the Iranian diaspora in effecting positive change in the U.S. and around the world, the Iranian Americans’ Contributions Project (IACP) has launched a series of interviews that explore the personal and professional backgrounds of prominent Iranian-Americans who have made seminal contributions to their fields of endeavor. We examine lives and journeys that have led to significant achievements in the worlds of science, technology, finance, medicine, law, the arts and numerous other endeavors. Our latest interviewee is Mahta Moghaddam.

Dr. Mahta Moghaddam is Professor of electrical engineering at the University of Southern California (USC) Ming Hsieh department of electrical engineering and the Director of New Research Initiatives at the USC Viterbi School of Engineering. Until 2011, she was on the faculty at the University of Michigan. She received her Ph.D. degree in electrical and computer engineering from the University of Illinois, Urbana, in 1991. From 1991 to 2003, she was with the NASA Jet Propulsion Laboratory (JPL), Pasadena, CA. Besides leading several research projects at JPL as well as the Science Chair. She has more than 25 years research experience in microwave systems and remote sensing, Dr. Moghaddam has pioneered new approaches for quantitative interpretation of airborne and space-borne radar imagery, developed new radar measurement technologies for subsurface and subcanopy imaging focused on characterization of water resources and arctic permafrost, and led the development of sensor web technologies for ground-based environmental data collection and dissemination. She and her group have also been strongly engaged in transforming concepts of radar remote sensing to high-resolution medical imaging, focused microwave therapy, and image-guided thermal therapy.

Dr. Moghaddam is the 2016 recipient of the NASA Honor Award “Outstanding Public Leadership Medal” for outstanding leadership in the advancement of microwave remote sensing technologies. She has also received numerous other research and education awards. She has co-authored over 100-reviewed journal papers and more than 200 conference papers. She is a Fellow of the Institute of Electrical and Electronics Engineers (IEEE) and the Editor-in-Chief of the IEEE Antennas and Propagation Magazine.

Tell our readers where you grew up and walk us through your background. How did your family and surroundings influence you in your formative years?

I was born in Tehran in 1965, and lived there with my family until mid-1982 when I finished high school. At the time, all of Iran’s universities were shut down and going through what was termed the “cultural revolution.” To continue my education, at the time I had no choice but to seek it outside of Iran. I arrived in the US later that year on a student visa, and started my undergrad studies at the University of Kansas in Lawrence in spring of 1983, joining my older sister who was already a graduate student there. I got my bachelor’s degree in electrical and computer engineering in 1986, and proceeded to complete a master’s degree and a PhD at the University of Illinois at Urbana-Champaign that were also in electrical and computer engineering, in 1989 and 1991, respectively. Junior high and high school education in Iran were (and are) rather rigorous, and additionally, for a few years there, I was fortunate to attend a special school that had an even-more advanced curriculum. So I recall that my first two years of undergraduate work in the US seemed like a walk in the park!

My first job after obtaining my PhD was at the NASA Jet Propulsion Laboratory (JPL), where I worked on various projects related to remote sensing of the Earth and planetary bodies using imaging radars. It was a great privilege to be given the chance to work on these projects and ultimately to lead some that were related to understanding the dynamics of the Earth’s environment, and in particular, the water cycle. What I learned at JPL, and the enormous scientific problems I was introduced to while there, have shaped much of my career. After being offered a faculty position at the University of Michigan in 2003, followed by a faculty position at the University of Southern California (USC) in 2012, I have had the chance to explore new methods for making more robust observations of the Earth system, and in particular, have focused on the dynamics and stores of water, and more recently, on the dynamics and vulnerability of the arctic permafrost systems. The combination of the fundamental science I learned in grad school and the practical methods and solutions I picked up at NASA/JPL have also resulted in the development of a different class of technologies. These are related to medical imaging and therapy systems that are based on the concepts of radar (that is, using radio waves for both medical imaging and thermal therapy of cancer).

When I started studying electrical engineering, I didn’t have a grand vision or plan for how I would end up using my knowledge. I was intrigued by the rapidly advancing technologies and wanted to have a part in it. I knew that I wanted it to be used to positively impact people’s lives or to make discoveries that enhanced human knowledge in some meaningful way (and therefore, once again, improve human life). I know this sounds like a generic motherhood-and-apple-pie statement, but at least it was a starting point to keep myself in check, answering the “so what?” question as I made decisions at each step of the way. Growing up, the concepts of seeking in-depth and well-rounded knowledge and making a difference were very strongly taught and expected by my parents and reinforced by the various schools I attended, so the overall “mission statement” was there all along. There was no other way to do things. I just had to (and continually have to) figure out the details!

In my formative years in grade school through high school, many social and scientific ideals were formed in my mind by reading literary and science fiction classics including the works of Leo Tolstoi, Romain Rolland, John Steinbeck, Anton Chekhov, Graham Greene, Bertolt Brecht, Mark Twain, Victor Hugo, Isaac Asimov, and Jules Verne, among others. Music was also another immense influence — growing up listening to traditional Persian music at home, and later learning to play western classical piano became, in an unexplainable way, a glue for consolidating otherwise disparate inputs. I feel extremely fortunate to have been allowed and encouraged by my parents to explore along many different paths, and to be challenged to reconcile the cultural, social, political, and scientific contradictions of what I was reading and observing during those early years of life. Much of this time was during the Iranian revolution and post-revolutionary turmoil; it was a time of many contradictions. I learned to observe and try to understand before passing judgment, making a decision, or reacting. The consequences could otherwise be dire. It was a good primer for the scientific method, although it had nothing to do with nominal science!

You received a number of awards and honors for your research, mentorship. and teaching. What were the significant accomplishments that led to these?

I am humbled by receiving research recognitions and awards, including the 2016 NASA Outstanding Public Leadership Medal Honor Award (for leadership in advancement of microwave remote sensing), several NASA Group Achievement Awards, and other university and professional society awards. Many of these have been for the development of new measurement methods, instruments, and algorithmic technologies for radio wave (or microwave) observations of the Earth’s environment, and especially for observations of permafrost as well as the components of the water cycle such as soil moisture and groundwater. With the help of my wonderful group of graduate students, post-doctoral researchers, and other team members, we have developed state-of-the-art technologies, for the first time, for mapping water content in soils, down to the root zone of plants, with high accuracy and over rather extensive areas with diverse types of land cover. This information is critical for understanding how the ecosystems function in response to availability of water, which in turn is crucial for understanding the global water and carbon cycles. While there is a general understanding that plant growth responds to water availability (think of your house plant, then think about whether it grows or wilts in response to your watering it), no one had previously held the specific information about root zone soil moisture to be able to quantify this relationship at large spatial scales. Much of the global variability of greenhouse gases can be explained by knowing how much water is available to plant roots, then projecting how that translates into carbon sequestration or release into the atmosphere. So what we are able to provide with our radar technologies has the potential to reduce the uncertainty about climate projections due to ecosystem function. Many years of our technology development with large teams of researchers are now making this possible.

Regarding teaching and mentoring awards — the credit goes to my students and mentees for keeping me on my toes and helping me remain a student at heart. Teaching and learning, in my opinion, are one. It is hard to talk about specific accomplishments that have led to receiving education awards, but I hope in some way those are a consequence of having successful students! Many of my former graduate students and post-docs are now themselves highly successful researchers, academics, and engineers. It has been through interactions with them that much of our technology advancements have become possible.

What has been your personal key to success? What were the biggest inspirations for your career?

Regarding the environmental remote sensing aspect of my work, what drives me at the very high level is curiosity about how the Earth system works and how our modern-human behavior may be impacting it, possibly throwing it off its natural balance. I can’t really answer these questions on my own or immediately by using my engineering tools, so moving a little farther below that high level, I am interested in having a role in providing objective, tractable, consistent, and validated data and information about the Earth system (specifically the water cycle) to scientists who can answer those high-level questions.

I believe the key to success is a combination of a gut-level curiosity and interest, hard work, objectivity, and serendipity. If you are genuinely interested in solving a problem, and you have or can get the tools to do so, you will eventually do so. Circumstances are important, though. Not every hard-working and curious person has the chance to reach their goals. I’ve therefore learned to look diligently for opportunities, appreciate them, and grab them if I can.

Biggest inspirations have come from people, places, and events (sounds like an NPR radio quiz show, doesn’t it?).

People, of course, have been the main influencers, starting with my parents, who had and have unfailing support while setting high expectations. I’ve also had great fortune to have incredible mentors and inspiring friends at every stage of my life. I would actually also give special credit to “difficult” people over the years, who in strange ways helped me learn tolerance and value compassion.

Events, which also involve people, have been undeniably important. For example, as my contemporaries would probably agree, the 1979 revolution in Iran was what shaped our world view to a large extent.

And places have been especially important for me because they have shaped key parts of my environmental research agenda. I still remember the first few times that I spent time out in the field in the boreal forests in Canada in the 1990s, and later in the arctic regions of Alaska both in the field and flying over while collecting data, and realizing the importance of our environmental research to these enormous but vulnerable places on Earth. I understood how little we knew about these places, and that there was so much that we needed to know, ASAP! Additionally and quite importantly, I come from [Iran], and now live [in southern California], both water-scarce regions. The question of what will happen to large and increasing populations around the world in water-scarce environments is huge. How will we feed ourselves, how will the population distributions change, and how will we adapt to the ensuing changes? Answering these requires a scientific and engineering approach. We can’t just wing it, and we can’t delay in dealing with it. Considering that more than 80% of freshwater globally is used for agriculture, we need more information and better tools to optimize our use of fresh water for growing food. This is one of the most important human-scale issues that we have to tackle, and is a key part of what drives and inspires my and my team’s environmental research. Our work on developing radar technologies for mapping root zone soil moisture is directly related to this issue.

Your fields of research have covered a wide range — from development of sensor systems and algorithms for high-resolution subsurface and subcanopy characterization to microwave cancer treatment systems. What binds these areas together?

The common thread in my research is the use of radio frequency (RF) waves, sometimes also called microwaves, for both imaging and heat delivery applications. Most people are familiar with “microwaves” in the context of the common kitchen appliance that heats food. The physics associated with this appliance is that when microwaves impinge on materials that have water content, they can penetrate but they get attenuated as they try to propagate inside the material. For food, this attenuation process results in generating heat. The higher the water content, the stronger the degree of attenuation. If a high power source of microwaves is used, such as the common microwave oven in our kitchens, a lot of heat is deposited as a result of this attenuation process. Your cell phone also uses microwaves, but the power levels are extremely low compared to the microwave oven, so that while we can use the microwaves for delivery of communication signals, there is no appreciable heating or penetration for normal durations of a phone conversation, for example.

Now with this background, consider using microwaves of very low intensity (similar to cell phone signals) for gathering information about what’s under the ground surface down to the root zone of plants. That’s exactly what we do with our radars for mapping water content of soils. We send microwaves from our radar transmitters that are onboard airplanes or spacecraft, and measure the signals that are returned (or “scattered”) to the radar. Through a series of computational algorithms and models, we convert the measured scattered waves into maps of quantities such as root zone soil moisture. We comply with all sorts of regulatory requirements to ensure safety and compatibility with other existing microwave services. While many researchers have used radars for environmental mapping or target tracking purposes, the use of the lower-frequency radars for subsurface mapping applications is new and one of our main contributions to environmental studies. A similar approach can also be used for imaging the human body. If low-power microwaves are used (in intensities that do not generate measurable heat), we can form images of the interior of the body. This method of medical imaging has the advantage of being non-ionizing (compared to X-rays, for example) and therefore harmless.

Circling back to the use of microwaves in heat delivery applications, we have also developed a precision-targeting method for treating tumors (including cancerous tumors) with high-power microwaves. Here, the purpose is indeed to heat up a specific region in the body so that the target tumor is ablated — that is, destroyed by increasing its temperature. We have shown in the laboratory that we can significantly elevate the temperature of a treatment zone to ablation levels while keeping the temperature of surrounding areas at safe levels. But our more important contribution in the medical thermal therapy applications is being able to monitor the three-dimensional temperature map of the treatment zone while thermal treatment is being administered by a surgeon. Nowadays, thermal treatments using laser or RF probes are being used in a number of situations where invasive surgery is not an option or not the best option (such as some tumors in the brain or the liver). The problem is that it is not easy to monitor the heat being deposited by these probes, so the surgeon either has to do the treatment in an open loop (that is, without feedback as to whether the treatment is correct or complete), or through expensive and time-consuming means such as MRI imaging. Our microwave-based methods will make it possible to provide real-time feedback to surgeons so that they can deliver the ablation treatment accurately and rapidly.

In your view, what is the biggest challenge with which your field is currently grappling?

I believe that one of the biggest challenges that we are facing today is a stagnating interest in science and engineering among the younger generation. Doing in-depth scientific work requires focus and sometimes requires months or years of persistence before you see meaningful results. This has always been a challenge in attracting young researchers, but it may be more of a challenge now with so many high-tech distractions, fast-news on social media, and the appetite for results-now. To be a successful scientist, I still believe that you need to be highly dynamic and on the look-out all the time (see above under question 3), but you also need to have a certain level of introspection and quiet thinking to let the inputs gel together and connect. We need to be teaching this aspect of discovery some more, and to show the students how personally and societally rewarding that can be.

On a positive note, though, I believe the younger generation is more courageous in asking tough questions and expecting impact. So they are indeed asking the “so what” question more frequently now. They also have much more access to information and easy ways to look up scientific literature. I have high hopes that the pace of discovery will become even higher, and that we will eventually have higher numbers of students seeking knowledge and careers in the sciences and engineering.

Can you share your thoughts on your Iranian-American identity? What does it mean to be an Iranian-American to you?

I feel very fortunate to have the benefits of my dual backgrounds. The Iranian heritage and spending the first 16–17 formative years of my life in Iran are a point of pride for me, and one of the reasons for having developed a deep appreciation for how science and technology can and must impact human life. I am also extremely proud of, and grateful for, my American home of the past 3 and a half decades. I don’t know of any other country that is so welcoming of immigrants, providing them with the same opportunities as those for its native-born citizens. Being an Iranian-American to me is to appreciate and give credit to both backgrounds, adopt and accentuate their positive aspects, and be cognizant of any shortfalls or negatives. It’s a happy continuum!