Koichi Ito is a Professor Emeritus and Visiting Professor at the Center for Frontier Medical Engineering, Chiba University, where he served as Deputy Vice-President for Research, from 2005 to 2009, and as Director of the Center for Frontier Medical Engineering, from 2009 to 2015. He is also a Visiting Professor to Hiroshima University, Japan, since 2015, and an Honorary Professor of Xidian University, China, since 2019. Ito served as 2018 President-Elect of the IEEE Antennas and Propagation Society (AP-S) and was the 2019 AP-S President. He is an inaugural member of IEEE OJAP’s Advisory Board.

Ito has made significant contributions in the research and development of small antennas for mobile communications and microwave antennas for medical applications such as cancer treatment. He has pioneered technologies for the evaluation of the interaction between electromagnetic fields and the human body by use of human-equivalent phantoms, and has advanced antenna systems for body-centric wireless communications. He is an IEEE Life Fellow and has received numerous awards for his research and service. In 2020 he earned one of the highest awards from the International Union of Radio Science (URSI), the Balthasar van der Pol Gold Medal, "for contributions to research and development in the fields of medical applications of electromagnetic waves and their evaluation using human-equivalent phantoms".

An influential expert and truly inspirational mentor of our Antennas and Propagation (AP) community, he shares his career path, reveals interesting aspects of his research work, and provides useful advice to young researchers entering the AP field.

What is your background and how did you become a researcher in your field?

When I was a schoolboy in Nagoya, Japan, I was into amateur radio. I still remember that I made an antenna called as HB9CV with a big help of my father who built a 10-meter-high tower for the antenna. I joined the Tokyo Institute of Technology as an assistant professor after graduating a university. My boss was Prof. Naohisa Goto who was running an antenna laboratory. At that time, a research on microstrip antennas had emerged and many researchers were tackling various patch antennas. I was particularly interested in circularly polarized series-fed microstrip array antennas without using patch antennas. An idea came to me that a combination of a dipole and a slot arranged along a microstrip line can create circular polarization regardless of its terminal condition. I was eager to continue studying the antennas after moving to Chiba University. It was hard but a kind of fun to start my own small laboratory with a couple of students from scratch.

It was easy for me to forget time when immersed in the study.

You have received a number of awards for your research. Which significant accomplishments led to these distinctions?

I feel so humbled to have received the awards, particularly the 2020 Balthazar van der Pol Gold Medal from URSI (International Union of Radio Science). The citation reads: "For contributions to research and development in the fields of medical applications of electromagnetic waves and their evaluation using human-equivalent phantoms." I am very grateful to the former students and staff of my laboratory as well as to my friends and colleagues who have supported my nomination.

Although I started my research career with antennas for communications, I was interested in microwave antennas for cancer treatment as well. In 1980’s and 1990’s, many microwave researchers were studying on external applicators using waveguide antennas or patch antennas. I was convinced that thin internal antennas were more promising for treatment of deep-seated tumors. I proposed thin coaxial-slot antennas for microwave hyperthermia which have been applied to clinical use. For R&D of coaxial-slot antennas, we needed to devise a reliable evaluation system utilizing human-equivalent phantoms instead of edible meat. After a great deal of trial and error, we developed various human-equivalent semi-solid physical phantoms. Interestingly, such semi-solid physical phantoms have been widely used by companies and universities for evaluation of interaction between antennas and the human body.

When I was serving an AP-S Distinguished Lecturer for five years, I gave many talks on these topics in many different countries and regions. I believe that my talks inspired young researchers and students to undertake antenna-related study.

…I was fortunate to have collaborated with medical doctors who were interested in our research work… such a collaboration is essential for the research in medical applications of electromagnetic waves.

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

Well, I have tried to set much value on novelty and originality in my research. It was easy for me to forget time when immersed in the study. I believe it was quite helpful to me to serve a few professors with different topics and personality when I was an assistant professor. In addition, I think I was fortunate to have collaborated with medical doctors who were interested in our research work.

I have attended numerous international conferences mostly relevant to antennas, hyperthermia and microwaves. Before or after the conference, I have usually visited a couple of laboratories to meet and discuss with my friends and colleagues. I have sometimes drawn much inspiration from them.

The late Prof. Jim James at the Royal Military College of Science (RMCS), UK, was a big inspiration to me in my early days. He invited me to stay at his house a few times when I attended conferences in UK. I had learned a lot from him about not only research but also an outlook on life. Whenever I met Prof. James, he always asked me “Why are you studying such an antenna for hyperthermia?” and “What is the best antenna for the purpose?”

When I served Director of the Center for Frontier Medical Engineering, Chiba University, and a Vice-President of the Japanese Society for Thermal Medicine (JSTM), I had lots of chances to discuss and collaborate with medical doctors in various researches on cancer treatment. I have drawn another inspiration from them. I believe such a collaboration is essential for the research in medical applications of electromagnetic waves.

…the concept of human-centric antennas could be used to mitigate mutual interference between different antennas placed closely… the use of a common antenna for different purposes could reduce the number of antennas needed, which would become beneficial not only to the human body but also to our environment.

Your fields of research have covered a wide range — from small antennas for mobile communications and antenna systems for body-centric wireless communications to microwave applications for cancer treatment. What binds these areas together?

The purposes and functions of these antennas look considerably different, but all the antennas are commonly used in the vicinity of a human body. This led me to the concept of human-centric antennas, namely, antennas specifically designed for use in or near the human body, more than 10 years ago. It was also a title of my keynote talk at EuCAP 2017.

The concept of human-centric antennas can be applied as a unified approach to deal with such antennas for different purposes and functions. Generally speaking, the mathematical problem of an antenna that is placed close to or in the human body may be considered as a so-called “boundary value problem,” in which the human body itself is treated as a complex lossy medium. In principle, the electromagnetic fields generated around the antenna could be obtained by solving Sommerfeld integral equations. As one of the advantages of this theoretical approach, we could distinguish among three different waves—namely, space waves, surface waves, and bulk waves—generated by the antenna. However, considering the difficulty of this approach and its lack of popularity, individual cases involving antennas in or near the human body are usually addressed appropriately in a specific manner by means of numerical or computer simulation.

Nevertheless, the concept of human-centric antennas could be used to further mitigate potential risks, such as mutual interference between different antennas placed closely. In addition, promoting the use of a common antenna for different purposes could reduce the number of antennas needed, which would become beneficial not only to the human body but also to our environment.

Theranostics can shorten a stay in hospital for patients and help bypass some of the undesirable biological effects that may arise when diagnostics and treatment are employed separately...these will significantly improve the quality of life of patients.

Your contribution in the field of medical applications of electromagnetic waves has been recognized through the Balthazar van der Pol Gold Medal. Recently, there has been much talk about “theranostics” and their promising role in cancer treatment. How can microwave-based theranostic devices transform healthcare?

Recently, the term “theranostics” has been used as a combination of therapeutics and diagnostics particularly in cancer treatment. In a clinical situation, drugs, radiation, ultrasound or electromagnetic waves are sometimes combined to diagnose and treat medical conditions simultaneously or sequentially. For example, a compact and thin microwave-based theranostic device was developed and reported. The device can act as an implantable sensor to detect malignant tumor and as an applicator for thermal ablation. Another example is a prototype of breast cancer treatment system which includes an ultrasound transducer array for thermoacoustic tomography and a microwave phased antenna array for hyperthermia.

It is obvious that theranostics can shorten a stay in hospital for patients. In addition, it seems possible to bypass some of the undesirable biological effects that may arise when diagnostics and treatment are employed separately. We are sure these will significantly improve the QOL (quality of life) of patients. Although it seems quite challenging to achieve this goal, it must be tremendously beneficial not only to patients but also to hospitals and medical doctors.

What advice would you give to a young researcher trying to attend an international conference?

If a young researcher needs to select an international conference to submit his/her paper, I suggest visiting websites of relevant conferences and looking into essential information in the past few years. If he/she submits a paper for the first time and has no preference, then I suggest a flagship conference such as an AP-S annual symposium. When submitting a paper, it is important to follow the instructions given by the conference organizer. Furthermore, most of the conferences have different supporting programs or awards for young researchers.

When preparing presentation slides, again it is important to follow the specific instructions provided. No need to say, but a rehearsal for the presentation is a must.

When attending an international conference in person, I recommend not only participating in relevant sessions but also discussing with other speakers and participants. I also recommend participating in extra events and social activities if possible. I believe these are good chances to know key persons and to make new friends.

…OJAP accepts not only typical research articles but also review or overview articles … publishes papers on mature topics as well as on emerging topics in other engineering and science fields that are dependent on antennas and propagation.

OJAP was launched under your leadership with the aim of serving openness and speeding up innovation. What sets OJAP apart from other journals in the field?

In 2019, the AP-S decided to launch OJAP as the first gold fully open-access journal of the Society when the IEEE seriously urged its Societies to establish their own open access journals. The AP-S appointed Prof. Konstantina Nikita as the inaugural Editor-in-Chief.

I believe that Prof. Nikita mostly answered to this question in her article titled “Meet the Editor-in-Chief” appeared in the OJAP Focus. Nevertheless, I would like to emphasize that OJAP accepts not only typical research articles but also review or overview articles without imposing limits on article length. Also, OJAP publishes papers on mature topics as well as on emerging topics in other engineering and science fields that are dependent on antennas and propagation.

As a good and timely example, OJAP has recently published a review article entitled “Next-Generation Healthcare: Enabling Technologies for Emerging Bioelectromagnetics Applications” which is 28-page long and contributed by 17 co-authors.