Professor Luk Kwai-man

Engineering the future

By : Professor Luk Kwai-man, Chair Professor, Department of Electronic Engineering

To address future needs in post-5G wireless communications, we have extended our research to terahertz technology.

I think this is what an engineering researcher should do. Engineering science is a profession that shapes the future.

Yet it would be wrong to assume that antenna design simply means faster and more data transmission. I have been studying antennas for more than thirty years, during which time I have designed smaller and thinner antennas, antennas made with flexible materials, liquid antennas, antennas with electronic scanning property, and antennas with precise positioning function. All these developments have been enacted in response to the needs of the world.

Take the water dense dielectric patch antenna that we presented a few years ago as an example. The use of pure water has a number of advantages: it is easily accessible so the cost is low; it is a safe material; it is transparent so it can be designed aesthetically; and since it is transparent, it can be conveniently integrated with solar cells to realise a dual-function design.

An example of the antenna the CityU team is working on for 5G communication. The antenna has a lot of functions, and is not limited to telecommunication. It can be applied to medicine, the military and space programmes. For example, my colleagues and I were working recently with some senior medical professionals on applications of radio waves, including a study on electromagnetic protection, the use of electromagnetic body imaging to detect abnormalities in the body, and using microwaves to soften blood clots in stroke patients.

I always take account of what I have in hand— this means my time and my resources. I will then set a goal for the coming few years. For instance, contributing my knowledge of antennas to the medical field is my present goal.  I believe small, incremental steps lead to significant gains.

Looking to the future

A liquid antenna My first encounter with antenna and microwaves dates back to the 1980s when most people thought the antenna basically meant fishbone-like TV antennas on the roof or the rabbit ear antenna on radios. The smaller size microstrip antenna was just beginning. The study of antenna was not particularly popular and did not guarantee any promising future, but I worked on it anyway.

Yet today, microstrip antennas are universal. The word “universal” is by no means exaggerated. Microstrip antennas are found in everyone’s smartphones today. Had I turned away looking for other disciplines that might have brought me fame and fortune, I would not have achieved my exciting antenna career today.

Don’t give up

I have collaborated with many antenna industry partners over the years and on several occasions they were negative about my designs; but I never backed down. I am always optimistic about improving my designs and earning appreciation. This was the case when my L-shaped probe fed microstrip antenna invention did not receive positive feedback from the industry.

A circularly polarized magneto-electric dipole array antenna developed by Professor Luk and his team. Back then traditional probe fed microstrip antennas usually had a narrow bandwidth, ranging from 2% to 3% only. So some twenty years ago, we presented the L-shaped probe fed microstrip antenna to the world. This piece of technology increased relative bandwidth to 30% while keeping reasonable radiation properties.

But industry found the back radiation too strong and the antenna impractical. Such criticism of your brainchild could be disheartening, but I tried to refine my work, confident that we could find a solution.

In fact, the negative comments motivated me to fine-tune my design and I eventually came up with the magneto-electric dipole antenna that possessed stable radiation patterns, a wide impedance bandwidth, low cross polarisation and low back radiation. The work was better received second time round.

Be connected

Professor Luk (left) at the 2018 New Fellows’ dinner of the Royal Academy of Engineering. Success never comes from a single person’s efforts. We were able to establish the State Key Laboratory of Terahertz and Millimeter Waves in 2008 thanks to support from CityU and peers in the Department of Electronic Engineering. We work as a team and contribute to our projects wholeheartedly, and we share a good laugh afterwards. Professional and psychological support is priceless, further propelling our research. Sincerity and honest communication will definitely lead to advancement.

I have studied antenna for over thirty years. I still love what I do, and I still look to the future. I do not surrender easily. With my colleagues, we will advance together and thus contribute to society. By helping the world, success will come to you.