Antenna theory and design

Electromagnetic waves are launched and received by antennas. Antennas are used in many applications, such as wireless communications, radar systems, radio-astronomy, medicine and security scanners. Our research is focused on optimal antennas, arrays, lens antennas and leaky wave antennas.

1) Optimal antennas: Given a volume for an antenna, what is the best possible impedance bandwidth? Does constraints like a high directivity or a narrow beam influence the best possible bandwidth, a first answer can be read from the graph to the right that shows the trade-off between directivity and (in essence) reciprocal relative bandwidth. Research on optimal antennas aim to answer questions of this and similar type, e.g. what is the possible bandwidth of an antenna under different constraints. Is it possible to realize antennas that reach the constraints? For more information about optimal antennas, please contact Prof. Lars Jonsson (

2) Arrays: At ETK, we work on the development of new analytic and numerical methods for the design of advanced antenna arrays. Investigations of strongly coupled antennas, as illustrated in the figure, but also antennas where the RF front-end is closely integrated with the array. The applications include communication, sensors and radars, and is in close collaboration with Swedish industries. For more information please contact. Prof. Lars Jonsson (

3) Lens antennas: We are also working in lens antennas for high frequency. For example, we make use of Luneburg lenses to produce directive and steerable beams at given directions. Particularly, these lenses can be applied for satellite communications and 5G. At ETK, we are focusing our research activities in two innovative techniques: Transformation optics and higher symmetries. The work on lens antennas is led at KTH by O. Quevedo-Teruel (

4) Leaky-waves antennas: Finally, we are focusing our research activities in the development of low-dispersive leaky-wave antennas. These antennas possess low-cost and simple feeding networks and they can be employed to produce very high directivity with low-side levels and high radiation efficiency. The research on leaky-wave antennas is led at KTH by O. Quevedo-Teruel (

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