In the world of engineering, certain disciplines are often shrouded in mystery. In the 2023 study “A Practical RF Engineering Curriculum for Engineering Technology Students,” D. Kim highlights that Radio Frequency (RF) is one of the most challenging subjects to teach.
This difficulty stems from two primary factors: the rigorous theoretical requirements in physics and mathematical modeling, and the prohibitive cost of essential equipment, such as network analyzers, which limits hands-on training in many undergraduate labs.
Antennas, situated at the intersection of pure physics and high-end electronics, lie at the heart of this complexity. To demystify this fascinating field, we sat down with Dr. Adrien Laffont, a PhD in Electromagnetics and High-Frequency Systems who has specialized in antenna measurement for the past four years.
In this interview, Dr. Laffont shares his pedagogical vision, moving from concrete utility to theoretical mastery, while revealing his approach to understanding fundamental concepts and the real-world constraints of industrial antenna design.
Learning antennas: A step-by-step pedagogical approach
How should you start learning about antennas?
I believe that learning about antennas must begin by demonstrating their utility in the real world, even before diving into theory. Antennas are everywhere around us: in phones, satellites, and all communication systems. Understanding this provides meaning and sparks students’ interest. It is then important to make things tangible: showing real antennas, performing measurements, and allowing students to handle hardware. Seeing and touching makes the theory far less abstract.
Once this foundation is laid, concepts and models can be introduced more naturally. At advanced levels, such as a Master’s degree, the objective is not just to understand, but also to apply and adapt these concepts in order to innovate.
How would you define an antenna?
An antenna is an electrical device designed to emit and/or receive electromagnetic waves. It ensures the transition between a guided electromagnetic wave, for example, in a cable, and a radiated electromagnetic wave propagating through space or the atmosphere, and vice versa.
The term “antenna” is generally used for systems operating from radio frequencies (RF) up to millimeter waves, or even terahertz (THz). As frequencies increase further, we approach infrared and then visible light: we then speak of optical devices, such as lasers or infrared and visible cameras, even though the transition between these domains remains progressive.
What are the fundamental concepts for understanding how an antenna works?
To approach antenna operation simply, it is useful to see it initially as a system capable of emitting an electromagnetic wave in a preferred direction. Depending on the application, that direction can vary significantly.
For example, to communicate with a satellite from a ground station, it is preferable to concentrate energy in a precise direction to optimize transmission. Conversely, in the case of a mobile phone, the position of the relay antenna is not known in advance: it is therefore more relevant to radiate across multiple directions. This spatial distribution of radiated energy is described by a key quantity called the radiation pattern, often characterized by its beamwidth and main lobe direction.
Another important notion is efficiency. Like any electronic component, an antenna has losses. If a certain power is injected at its input, only a portion will actually be radiated, with the rest dissipated as heat. This is known as radiation efficiency. The radiation pattern and efficiency together constitute what are called radiation performances. Although these concepts are often introduced in the context of transmission, they also apply in reception: some antennas are, for example, more sensitive to signals arriving from specific directions.
One must also consider that an antenna is always connected to an electronic circuit. This introduces a fundamental electronics concept: impedance. For efficient power transfer, whether in transmission or reception, the antenna’s input impedance must match that of the connected circuit. When impedance mismatch occurs, part of the power is reflected and lost, a phenomenon measurable through indicators such as VSWR or return loss. A simple analogy is plumbing: connecting two pipes of very different diameters without a transition causes losses and inefficient flow.
Beyond these, other fundamental notions are worth exploring as you deepen your knowledge, such as polarization or antenna gain. All these concepts allow for a better understanding and comparison of antenna performance. It is also essential to keep in mind that an antenna’s performance depends heavily on frequency: each antenna is designed to operate over a specific frequency band, directly linked to its application, telecommunications (including 5G and IoT systems), localization, or radar.
Summary of fundamental antenna concepts
| Concept | Definition |
| Radiation pattern | Describes the spatial distribution of electromagnetic power that an antenna emits or receives in different directions around it. |
| Radiation efficiency | Represents the ability of an antenna to convert electrical power into electromagnetic waves (in transmission) and, conversely, to convert received waves into electrical power (in reception). |
| Input impedance | A characteristic quantity of the antenna: when the antenna’s impedance matches that of the circuit, the transfer of current and power is optimal. |
| Frequency band | The range of frequencies over which the antenna operates effectively for the intended application, in direct connection with impedance matching and radiation performance. |
In your opinion, which antennas are the most accessible for beginners?
The approach is similar to many engineering disciplines: start with simple cases and gradually increase complexity. In the case of antennas, the most accessible are wire antennas (such as dipoles or monopoles), aperture antennas (for example, horn antennas), and planar antennas (such as patch antennas).
These are particularly interesting starting points because they can be described with analytical or semi-analytical models, simulated numerically with relative ease, and readily obtained for hands-on measurements.
These are, in a sense, “elementary” radiating elements — essential to master before tackling more complex structures, such as antenna arrays. And above all, keep in mind that an antenna is always tied to an application: depending on the need, one technology will be favored over another, each with its own advantages and trade-offs.
From academia to industry: the reality of RF engineering
How did you become passionate about antennas?
Becoming passionate about antennas… I’m not sure it’s an immediate passion. Rather, I think it’s a journey, a path that gradually leads you to take an interest in, and then to love, a field. And that experience is very specific to each person.
In my case, I was drawn to engineering, to a technical field close to applied physics. My move toward antennas was largely shaped by the people I met along the way: teachers, researchers, and professionals from industry. In my second year of engineering school, I particularly enjoyed a course on antennas and RF, largely thanks to the teacher’s pedagogical qualities. I then had the opportunity to carry out a project with him, which led to a first internship on the subject, then a second.
Gradually, my interest deepened: in my final year, I specialized in antennas and RF, then pursued a doctorate in the field. Ultimately, I find the subject itself genuinely compelling. Antennas span many areas: there is pure physics, notably electromagnetism, but also very concrete engineering constraints, such as the performance targets for each application and how they are measured. In the end, it is a blend of theory, practice, and real-world constraints that makes this field so rewarding.
How does academic training compare to working in the industry?
I’ll focus more specifically on antenna measurement, which is a somewhat particular aspect of the field. Today, there are relatively few training programs dedicated specifically to antenna measurement. Most engineers working in this area have a background in antennas or electromagnetism, complemented by more or less significant hands-on measurement experience.
As in many engineering disciplines, there is a natural gap between academic learning and industrial reality. At university, you primarily acquire theoretical foundations and fundamental tools: understanding physical phenomena, designing and simulating antennas, and carrying out initial measurements. In my view, this stage is indispensable, the antenna field is technically demanding and requires solid grounding.
Industrial reality then introduces dimensions that are less addressed in academic training: engineering constraints such as costs, deadlines, performance trade-offs, and physical limitations like size, weight, or electromagnetic compatibility (EMC). Bridging that gap is part of what makes the profession both challenging and stimulating.