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.

Investigation of transitions for use in inverted microstrip gap waveguide antenna arrays

Abstract: The main purpose of this work is to create good transitions for inverted microstrip-based versions of gap waveguide that are used to feed slot or horn antenna arrays. Two new millimeter-wave transitions from inverted microstrip gap waveguide to rectangular waveguide are presented. Both geometries are similar and consist of a planar probe, which contains a rectangular patch or T-section. The planar probe is inserted inside the rectangular waveguide through an opening made in the broadside wall of the waveguide. The main difference between the two geometries is that one of them extends upwards and the other one downwards with respect to the planar inverted microstrip gap waveguide circuit. The simulated S-parameters show promising results.

Presentation of the spectral electric and magnetic field integral equations used in G2DMULT for analyzing cylindrical structures of multimaterial regions

Abstract: When dealing with electromagnetic problems of three-dimensional (3D) elements, such as dipoles, microstrip patches, and slots, in the vicinity of two-dimensional (2D) structures, it is very efficient to find the radiation characteristics of the 3D elements and the mutual couplings between them by using a spectrum of 2D solutions (S2DS). G2DMULT is a general algorithm that applies the S2DS technique to calculate the spectral Green's functions of 2D multiregion structures by using the method of moments (MoM). When these spectral Green's functions are used, the spectral electric and magnetic field integral equations (EFIE and MFIE) are needed to solve the 2D problems in the spectral domain. This Letter presents the spectral electric and magnetic field integral equations (EFIE and MFIE), their moment-method solution formulations, and the special expressions needed to handle the discontinuity of some field components at the material boundaries. Several numerical examples show that G2DMULT with these spectral EFIEs and MFIEs can provide accurate results compared with measurements. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 88–93, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10382

High efficiency 2×2 cavity-backed slot sub-array for 60 GHz planar array antenna based on gap technology

Abstract: This paper presents a two layer 2×2-slot element as a sub-array for 60 GHz planar array antenna based on gap waveguide technology. The proposed element consists of 2×2 slots in a gap waveguide cavity where the cavity is fed through a coupling slot from a ridge gap waveguide corporate-feed network in a lower layer. The 2×2-slot sub-array is numerically optimized in an infinite array environment. The designed sub-array shows the relative bandwidth of 11% with reflection coefficient better than ™13 dB over 58.2–65 GHz frequency band. A prototype of a 8×8-element slot array antenna is designed and fabricated in order to verify the simulations.

A new 2×2 microstrip patch sub-array for 60GHz wideband planar antenna with ridge gap waveguide distribution layer

Abstract: We propose a two layer planar antenna where a ridge gap waveguide corporate distribution network feeds a subarray of 2×2 radiating microstrip patch elements. There exists a coupling slot in the ground plane of the substrate layer which allows the excitation of the microstrip patch elements from the ridge gap waveguide layer. The ground plane of the substrate also serves the purpose of top metal layer for the ridge gap waveguide section. The proposed antenna is operating over 15% relative bandwidth covering 56–66 GHz frequency range with −12 dB reflection coefficient. The simulated directivity of the 2×2 element array is 11.5dbi at the center of the band. The simulated directivity for the 16×16 element array using the infinite array approach is found to be 28.7dBi.

Asymptotic transition region theory for edge diffraction. II. Calculation of diffraction losses in multireflector antennas

Abstract: For pt.I see ibid., vol.38, no.9, p.1350-8 (1990). Asymptotic formulas that can be used to calculate diffraction losses in a multireflector antenna without having to integrate rapidly varying fields over the reflector surfaces and the aperture are presented. Two kinds of losses caused by edge diffraction are considered: the reduction in antenna efficiency and the increase in spillover. The asymptotic formulas are obtained from the standard transition region field introduced in part I and are expressed in terms at the Delta rho defined there. >

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.