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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.


Papers
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Proceedings ArticleDOI
01 Jun 2009
TL;DR: In this paper, an improved theory for the uncertainty of measurements in reverberation chamber is obtained by including the error due to the direct coupling between the antenna under test and the wall-mounted antennas.
Abstract: We have presented an improved theory for the uncertainty of measurements in reverberation chamber. The theory is obtained by including the error due to the direct coupling between the antenna under test and the wall-mounted antennas. The theory includes the Rician K-factor that can be estimated from simple formulas, and an empirical mechanical stirring bandwidth B mech that is adjusted to get good agreement with the measured STDs. However, B mech is fixed for a given chamber and stirrer configuration. The new theory is able to describe variations of uncertainty with frequency and loading, and it can very well predict the degradation when platform and polarization stirring is not used. The validation of the theory is representative for efficiency measurements, but it will be equivalent for measuring total radiated power and receiver sensitivity.

28 citations

Proceedings ArticleDOI
01 Oct 1993
TL;DR: In this article, the authors introduce the concept of artificially soft and hard surfaces in electromagnetics, which are defined from the boundary conditions of the E-field by an analogy with soft-hard surfaces in acoustics.
Abstract: This paper give an introduction to the concept of artificially soft and hard surfaces in electromagnetics. The soft and hard surfaces are defined from the boundary conditions of the E-field by an analogy with soft and hard surfaces in acoustics. The electromagnetic soft and hard surfaces have polarisation-independent boundary conditions (at the centre frequency), in contrast to a metallic conductor that has different boundary conditions for the tangential and normal components of the E-field. This makes the soft and hard surfaces desirable in many practical antennas, in particular when dual or circular polarisation is required. The soft and hard surfaces are realised by providing a metal conductor by an anisotropic surface impedance. This can be obtained by providing it with corrugations, or with a strip-loaded dielectric layer. The most known application of the soft surface is in hybrid-mode horns, more commonly known as corrugated horns. The corrugated "soft" surface is also often called "chokes" and used to reduce coupling and sidelobes in particular directions (e.g. choke-horn). The hard surface has only been known a few years. Two of the most important applications of the hard surface are described in the present paper. The first is to design hard horns which have very high aperture efficiency for application in cluster feeds and arrays. The second is to reduce scattering from masts or struts that block the aperture or radiation fleld of an antenna. The paper also describes how known calculation methods now are extended to analyse these types of loaded surfaces.

28 citations

Proceedings ArticleDOI
10 May 2015
TL;DR: In this article, a V-band iris filter based on groove gap waveguide technology is presented, which does not need electrical contact between two constituting metallic surfaces, as it is needed in conventional hollow waveguides.
Abstract: This work presents a V-band iris filter, based on recently introduced groove gap waveguide technology. In this technology, it doesn't need to have electrical contact between two constituting metallic surfaces, as it is needed in conventional hollow waveguides. Therefore, it is cheaper to manufacture gap waveguide components, in particular in millimeter wave frequency range. In this work, square shape groove gap waveguide cavities are used as filter resonators. To realize the input/output coupling and also inter cavity coupling, two larger pins are used to act as an iris. A fifth order bandpass Chebyshev filter is designed with 1 GHz bandwidth at 59.5 GHz center frequency and a prototype is manufactured to validate the simulation results. Design process, simulated results, and measured results are presented here.

27 citations

Proceedings ArticleDOI
01 Jun 2009
TL;DR: In this paper, the authors presented the design of a simple transition from ridge gap waveguide to coaxial line transition and achieved a return loss of −10 dB over the frequency band of 12-15.75 GHz.
Abstract: This paper presents the design of a simple transition from ridge gap waveguide to coaxial line transition. First, a straight ridge gap waveguide with single transition on end is simulated. Then a ridge gap waveguide with two 90° bends is simulated with two transitions on each end. Available commercial FDTD simulation tool was used to design the transitions. A return loss of −10 dB was achieved over the frequency band of 12– 15.75 GHz.

27 citations

Proceedings Article
23 Mar 2009
TL;DR: In this paper, the relationship of coherence bandwidths and RMS delay spread in a reverberation chamber is investigated and the measured results are in good agreement with the theory. But the coherence coherence is controlled to be between 2.5 and 10 MHz by loading the chamber.
Abstract: This paper presents the derivation and measurements of the relationship of coherence bandwidths and RMS delay spreads in reverberation chamber. The measured results are in good agreement with the theory. The coherence bandwidths are controlled to be between 2.5 and 10 MHz by loading the chamber.

27 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a new type of metallic structure has been developed that is characterized by having high surface impedance, which 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.
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.

4,264 citations

Journal ArticleDOI
TL;DR: 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 sub-millimetre spectral range 55 671 m.
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.

3,359 citations

Proceedings Article
01 Jan 1999
TL;DR: In this paper, the authors describe photonic crystals as the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures, and 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.
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.

2,722 citations

Journal ArticleDOI
TL;DR: The potential of transformation optics to create functionalities in which the optical properties can be designed almost at will is reviewed, which can be used to engineer various optical illusion effects, such as the invisibility cloak.
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.

1,085 citations

Journal ArticleDOI
TL;DR: The 2017 roadmap of terahertz frequency electromagnetic radiation (100 GHz-30 THz) as discussed by the authors provides a snapshot of the present state of THz science and technology in 2017, and provides an opinion on the challenges and opportunities that the future holds.
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.

1,068 citations