Per-Simon Kildal

Bio: Per-Simon Kildal is an academic researcher from Chalmers University of Technology. The author has contributed to research in topics: Antenna (radio) & Electromagnetic reverberation chamber. The author has an hindex of 60, co-authored 504 publications receiving 13470 citations. Previous affiliations of Per-Simon Kildal include SP Technical Research Institute of Sweden & Norwegian Institute of Technology.

A fast calculation of impedances of dipoles near cylindrical structure by applying asymptotic waveform evaluation in a spectrum of 2d solutions

Abstract: A spectrum of 2D solutions (S2DS) applies the Fourier transform to 3D currents in the uniform direction of a 2D cylindrical structure to arrive into a spectral-domain problem which can be solved by 2D spatial techniques. In order to calculate the near fields that are needed for the calculation of impedance, the inverse Fourier transform must be performed. This usually requires a large number of 2D solutions in the spectral domain. By using the asymptotic waveform evaluation (AWE) method in S2DS, the inverse Fourier transform can be performed very efficiently, with only several 2D solutions in the spectral domain. This paper presents the fast calculation of the impedance of a dipole in the vicinity of a 2D cylindrical structure. The cases presented in this paper show that the calculation is accelerated seven times more than by using the direct S2DS method.

A microwave or millimeter wave rf part assembled with pick-and-place technology

Abstract: A radio frequency (RF) part of an antenna system, e.g. for use in communication, radar or sensor applications, is disclosed, as well as a method for producing such a part. The part comprises: a first conducting layer; a plurality of monolithic waveguide elements, each having a base and protruding fingers extending up from the base, arranged to form a waveguide along the first conducting layer; and a second conducting layer arranged on top of the first conducting layer, so that a gap is formed between the first and second conducting layers, thereby providing gap waveguides. The protruding fingers of the waveguide elements form a set of periodically or quasi-periodically arranged protruding elements forming a texture to stop wave propagation in a frequency band of operation in other directions than along intended waveguiding paths. This RF part is easy to manufacture, e.g. using pick-and-place equipment, and allows flexible design of passive and active networks, e.g. using combinations of various waveguide elements as building blocks.

Electromagnetic scattering from a circular cylinder with an anisotropic surface impedance due to an obliquely incident plane wave

Abstract: The series solution of the electromagnetic scattering from a circular cylinder with an anisotropic surface impedance due to an arbitrary plane-wave incidence is given The solution can be used as a canonical problem, and for validation of more general numerical methods or for exact calculations of the cylinder with the actual dimension of the realization of the surface impedance Examples are given for verification purposes © 1995 John Wiley & Sons, Inc

High-impedance electromagnetic surfaces with a forbidden frequency band

Abstract: A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Although it is made of continuous metal, and conducts dc currents, it does not conduct ac currents within a forbidden frequency band. Unlike normal conductors, this new surface does not support propagating surface waves, and its image currents are not phase reversed. The geometry is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements, and distributed in a two-dimensional lattice. The surface can be described using solid-state band theory concepts, even though the periodicity is much less than the free-space wavelength. This unique material is applicable to a variety of electromagnetic problems, including new kinds of low-profile antennas.

Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy

Abstract: Herschel was launched on 14 May 2009, and is now an operational ESA space observatory o ering unprecedented observational capabilities in the far-infrared and submillimetre spectral range 55 671 m. Herschel carries a 3.5 metre diameter passively cooled Cassegrain telescope, which is the largest of its kind and utilises a novel silicon carbide technology. The science payload comprises three instruments: two direct detection cameras/medium resolution spectrometers, PACS and SPIRE, and a very high-resolution heterodyne spectrometer, HIFI, whose focal plane units are housed inside a superfluid helium cryostat. Herschel is an observatory facility operated in partnership among ESA, the instrument consortia, and NASA. The mission lifetime is determined by the cryostat hold time. Nominally approximately 20,000 hours will be available for astronomy, 32% is guaranteed time and the remainder is open to the worldwide general astronomical community through a standard competitive proposal procedure.

Photonic crystals

Abstract: The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

Transformation optics and metamaterials

Abstract: Transformation optics describes the capability to design the path of light waves almost at will through the use of metamaterials that control effective materials properties on a subwavelength scale. In this review, the physics and applications of transformation optics are discussed.

The 2017 terahertz science and technology roadmap

Abstract: Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz–30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to 'real world' applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies.