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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 Article
01 Oct 2016
TL;DR: In this paper, the authors presented the design of a high efficiency corporate-fed 8 χ 8 slots array antenna in the 60 GHz band using four unconnected layers, which works as AMC, PCB microstrip feeding networks, groove waveguide cavity and radiation slots layer on the top.
Abstract: In this paper we present the design of a high efficiency corporate-fed 8 χ 8 slots array antenna in the 60-GHz band. The antenna is built using four unconnected layers — bed of nails, which works as Artificial Magnetic Conductor (AMC), PCB microstrip feeding networks, groove waveguide cavity and radiation slots layer on the top. The designed antenna shows a relative bandwidth of 14.63% with input reflection coefficient better than −15 dB and an overall efficiency larger than 70% with about 26.5 dBi simulated gain between 57 and 66 GHz.

6 citations

Proceedings ArticleDOI
01 Sep 2007
TL;DR: In this article, the similarity between the anisotropic soft surface, and the last decade's isotropic artificial magnetic conductor and in particular the so-called bandgap surface is discussed.
Abstract: Soft and hard surfaces for electromagnetic waves were defined in 1988. Here we will explain the similarity between the anisotropic soft surface, and the last decade's isotropic artificial magnetic conductor and in particular the so-called bandgap surface. It is summarized that a soft surface normally will have better performance than a bandgap surface when the purpose is to stop waves propagating along a surface for dual or circular polarization. We will also explain how the hard surface can be used to make cylindrical objects invisible, and that this was experimentally proven to have decent bandwidth in a journal article in 1996, ten years before the promised theoretical metamaterial cloak published last year. The invisibility is correctly and conveniently characterized in terms of an equivalent blockage width that characterizes the forward scattered field. There will be presented recent results in which the performance of hard surface cloaks and metamaterials cloaks are compared, showing the superiority of the hard surface cloak.

6 citations

Proceedings Article
01 Jan 2008
TL;DR: In this article, the intrinsic average mode bandwidth of the reverberation chamber is determined as it determines the averaged power transmission level of the chamber, and the number of independent samples in order to generate enough independent samples to improve the measurement accuracy.
Abstract: The reverberation chamber is basically a metal cavity with many excited modes which are stirred to create a statistical isotropic field environment with Rayleigh distributed magnitudes of the field [1]. The reverberation chamber used here is 1.8 m х 1.4 m х 1.2 m in size. The chamber makes use of frequency stirring, platform stirring, and polarization stirring to improve measurement accuracy [1], [2]. It has been used to measure antenna radiation efficiency and diversity gains [2]. For these measurements the intrinsic average mode bandwidth of the chamber is of interest as it determines the averaged power transmission level of the chamber [3]. It may also be sued to control the number of excited modes in the chamber, and thereby also the number of independent samples in order to generate enough independent samples to improve the measurement accuracy [4], [5]. Reverberation chamber can also be used to measure total radiated power and total isotropic sensitivity of active mobile phones [6], [7]. For such measurements the delay spread and coherence bandwidth are of relevance. Coherence bandwidth is defined as the frequency range over which the channel is correlated. When a signal at a certain frequency is transmitted through a reverberation chamber, several cavity modes will be excited. Each of these resonating modes can be characterized by its

6 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented a new uncertainty model based on the presence of an unstirred component of the transfer function, which was modelled by introducing an average Rician K-factor.
Abstract: Measurements in reverberation chamber (RC) produce data that are random, and therefore they need to be processed from the statistical point-of-view for obtaining the desired characteristics and the accuracy. The complex channel transfer function in the RC follows complex Gaussian distribution provided that the RC is well stirred. The authors have recently presented a new uncertainty model based on the presence of an unstirred component of the transfer function, which was modelled by introducing an average Rician K-factor. The model was validated in two RCs with translating mode-stirring plates, being able to correctly describe the improvement in accuracy by rotating the antenna under test, and by blocking the line-of-sight between this and the fixed RC antenna(s). In the present study, they apply this uncertainty model to four RCs with different settings (e.g. RC volumes, number of plates or fixed RC antennas, translating and rotating mode-stirrers etc.). For each RC, they examine the measurement uncertainty under different loading conditions. To repeat (during the different measurements) the actual mode-stirrer positions at which the transfer function is sampled, they conduct all the measurements with stepwise (instead of continuous) mode-stirring. The model is shown to work well for all the cases.

6 citations

Proceedings ArticleDOI
30 Dec 2008
TL;DR: The measured results show that the Eleven antenna is a flexible antenna that can be used with around 11 dB gain and arbitrary single or dual polarization in a Line-Of-Sight system and with 4 or 8 independent ports in a MIMO system, and it can easily be switched between these two modes by appropriate combination of the antenna ports.
Abstract: The purpose of the present paper is to investigate the MIMO performance of the L-band multi-port Eleven antenna. Both a single- and dual-polarized lab model are investigated, both having 4 ports per polarization. The 4 ports per polarization are normally combined in a 180 deg hybrid to produce sum and difference patterns, but we investigate them here as individual ports in an antenna for a MIMO system. The embedded element efficiency, diversity gain and maximum available capacity of both models have been measured in a Bluetest reverberation chamber. The measured results show that the Eleven antenna is a flexible antenna that can be used with around 11 dB gain and arbitrary single or dual polarization in a Line-Of-Sight system and with 4 or 8 independent ports in a MIMO system, and it can easily be switched between these two modes by appropriate combination of the antenna ports.

6 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