Proceedings of 1995 IEEE MTT-S International Microwave Symposium
A new step recovery diode (SRD) model for CAD is developed by considering the voltage ramp in the... more A new step recovery diode (SRD) model for CAD is developed by considering the voltage ramp in the SRD and using a DC measurement to extract a model parameter. This model can be directly used in commercial circuit simulators for designs of SRD circuits. Examples of using this model to analyse a comb generator and a frequency multiplier are given.<<ETX>>
[Conference Digest] International Conference on Millimeter Wave and Far-Infrared Technology: ICMWFT '90
In Finland the research into millimeter wave techniques started from the challenge of radio astro... more In Finland the research into millimeter wave techniques started from the challenge of radio astronomy 16 years ago. In 1973-74 a 13.7 m diameter millimeter wave telescope antenna was erected at the Metsahovi Radio Research Station near Helsinki. The telescope is owned and operated by the Helsinki University of Technology (HUT). Since 1975 several low noise telescope receivers for frequencies from 22 to 115 GHz have been built in the Radio Laboratory of HUT.
IEEE Antennas and Propagation Society International Symposium 1997. Digest, 1997
The optimization of a submillimeter wave hologram type of compact antenna test range (CATR) is st... more The optimization of a submillimeter wave hologram type of compact antenna test range (CATR) is studied with a combined analysis of an exact near-field aperture integration (physical optics) and a finite difference time domain (FDTD) method at 500 GHz. The effect of altering the feed horn radiation pattern is discussed.
2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2014
Coherent detection of very weak THz signals is important in astronomy, spectroscopy, and communic... more Coherent detection of very weak THz signals is important in astronomy, spectroscopy, and communications. We report on coherent up-conversion of THz radiation into the optical telecommunication range. All resonant phase-matched conversion can be achieved in a whispering gallery mode (WGM) resonator. Furthermore we present first results on WGM resonators that can be coupled to both THz radiation as well as optical fields allowing the study of non-linear interactions between the two frequency domains.
[Proceedings] IGARSS'91 Remote Sensing: Global Monitoring for Earth Management
A low-noise superheterodyne receiver has been designed and constructed for the ground-based monit... more A low-noise superheterodyne receiver has been designed and constructed for the ground-based monitoring of stratospheric ozone. The receiver detects the pressure broadened spectral line of ozone at 110.836 GHz with a total bandwidth of 1200 MHz. The front-end consists of a ...
IEEE Transactions on Antennas and Propagation, 1992
... Meters Art0 Lehto, Jussi Tuovinen, Olga BoriE, and Antti Raisien ... is The phase difference ... more ... Meters Art0 Lehto, Jussi Tuovinen, Olga BoriE, and Antti Raisien ... is The phase difference of the signals received by the antennas is #d + (bo, where (bo is the phase difference of the two channels leading to the power meter P3. ...
The spectral line receiving system at the 13.7 m radio telescope at the Metsähovi Radio Research ... more The spectral line receiving system at the 13.7 m radio telescope at the Metsähovi Radio Research Station is described. A cooled low noise Schottky mixer receiver in 72–115 GHz range is employed. The back end system comprises three acousto-optical spectrometers (AOS) with bandwidths of 11 MHz, 100 MHz and 600 MHz, of which only the 11 MHz AOS has been
2015 9th European Conference on Antennas and Propagation (EuCAP), 2015
The focus of this manuscript is an analysis of various design aspects of composite right-left han... more The focus of this manuscript is an analysis of various design aspects of composite right-left handed transmission lines (TLs) with emphasis on practical implementation to periodic structures. Existing used design procedures consider the influence of a period to guided wavelength ratio, coupling of parasitic fields, or fabrication inaccuracies to a limited degree. These factors become especially important for composite right/left handed (CRLH) TLs design increasing the frequency of operation. The result of this work is a detailed analysis of finite periodic transmission lines design with regard on the factors mentioned. The optimal value of the period to guided wavelength ratio was found to be 0.1-0.25 for the best trade-off between easy balancing of the unit cell and maintaining the applicability of the Bloch analysis.
2012 International Conference on Electromagnetics in Advanced Applications, 2012
ABSTRACT This paper discusses the prospects of millimeter-wave beam steering antennas, such as tu... more ABSTRACT This paper discusses the prospects of millimeter-wave beam steering antennas, such as tuneable high-impedance surface, dielectric rod waveguide with an integrated phase shifter, tuneable leaky-wave antenna, active reflectarray, and shaped lens antenna with an integrated switched feed array. In these antennas the necessary phase change for antenna elements can be achieved using various electronically tuneable elements, but in our case MEMS are used. Some early results of our investigations are presented.
Proceedings of 2012 5th Global Symposium on Millimeter-Waves, 2012
ABSTRACT In many emerging applications of millimeter waves, electronic focusing and beam steering... more ABSTRACT In many emerging applications of millimeter waves, electronic focusing and beam steering is needed. We present a survey of mm-wave beam steering antennas, where the necessary phase change for antenna elements is achieved using various electronically tuneable elements, e.g. microelectromechanical systems (MEMS), such as tuneable leaky-wave antennas, shaped lens antennas with integrated switched feed array, active reflectarray, tuneable high-impedance surface, and dielectric rod waveguides with integrated phase shifters. Some early results of our own relevant investigations are also presented.
Proceedings of 1995 IEEE MTT-S International Microwave Symposium
A new step recovery diode (SRD) model for CAD is developed by considering the voltage ramp in the... more A new step recovery diode (SRD) model for CAD is developed by considering the voltage ramp in the SRD and using a DC measurement to extract a model parameter. This model can be directly used in commercial circuit simulators for designs of SRD circuits. Examples of using this model to analyse a comb generator and a frequency multiplier are given.<<ETX>>
[Conference Digest] International Conference on Millimeter Wave and Far-Infrared Technology: ICMWFT '90
In Finland the research into millimeter wave techniques started from the challenge of radio astro... more In Finland the research into millimeter wave techniques started from the challenge of radio astronomy 16 years ago. In 1973-74 a 13.7 m diameter millimeter wave telescope antenna was erected at the Metsahovi Radio Research Station near Helsinki. The telescope is owned and operated by the Helsinki University of Technology (HUT). Since 1975 several low noise telescope receivers for frequencies from 22 to 115 GHz have been built in the Radio Laboratory of HUT.
IEEE Antennas and Propagation Society International Symposium 1997. Digest, 1997
The optimization of a submillimeter wave hologram type of compact antenna test range (CATR) is st... more The optimization of a submillimeter wave hologram type of compact antenna test range (CATR) is studied with a combined analysis of an exact near-field aperture integration (physical optics) and a finite difference time domain (FDTD) method at 500 GHz. The effect of altering the feed horn radiation pattern is discussed.
2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2014
Coherent detection of very weak THz signals is important in astronomy, spectroscopy, and communic... more Coherent detection of very weak THz signals is important in astronomy, spectroscopy, and communications. We report on coherent up-conversion of THz radiation into the optical telecommunication range. All resonant phase-matched conversion can be achieved in a whispering gallery mode (WGM) resonator. Furthermore we present first results on WGM resonators that can be coupled to both THz radiation as well as optical fields allowing the study of non-linear interactions between the two frequency domains.
[Proceedings] IGARSS'91 Remote Sensing: Global Monitoring for Earth Management
A low-noise superheterodyne receiver has been designed and constructed for the ground-based monit... more A low-noise superheterodyne receiver has been designed and constructed for the ground-based monitoring of stratospheric ozone. The receiver detects the pressure broadened spectral line of ozone at 110.836 GHz with a total bandwidth of 1200 MHz. The front-end consists of a ...
IEEE Transactions on Antennas and Propagation, 1992
... Meters Art0 Lehto, Jussi Tuovinen, Olga BoriE, and Antti Raisien ... is The phase difference ... more ... Meters Art0 Lehto, Jussi Tuovinen, Olga BoriE, and Antti Raisien ... is The phase difference of the signals received by the antennas is #d + (bo, where (bo is the phase difference of the two channels leading to the power meter P3. ...
The spectral line receiving system at the 13.7 m radio telescope at the Metsähovi Radio Research ... more The spectral line receiving system at the 13.7 m radio telescope at the Metsähovi Radio Research Station is described. A cooled low noise Schottky mixer receiver in 72–115 GHz range is employed. The back end system comprises three acousto-optical spectrometers (AOS) with bandwidths of 11 MHz, 100 MHz and 600 MHz, of which only the 11 MHz AOS has been
2015 9th European Conference on Antennas and Propagation (EuCAP), 2015
The focus of this manuscript is an analysis of various design aspects of composite right-left han... more The focus of this manuscript is an analysis of various design aspects of composite right-left handed transmission lines (TLs) with emphasis on practical implementation to periodic structures. Existing used design procedures consider the influence of a period to guided wavelength ratio, coupling of parasitic fields, or fabrication inaccuracies to a limited degree. These factors become especially important for composite right/left handed (CRLH) TLs design increasing the frequency of operation. The result of this work is a detailed analysis of finite periodic transmission lines design with regard on the factors mentioned. The optimal value of the period to guided wavelength ratio was found to be 0.1-0.25 for the best trade-off between easy balancing of the unit cell and maintaining the applicability of the Bloch analysis.
2012 International Conference on Electromagnetics in Advanced Applications, 2012
ABSTRACT This paper discusses the prospects of millimeter-wave beam steering antennas, such as tu... more ABSTRACT This paper discusses the prospects of millimeter-wave beam steering antennas, such as tuneable high-impedance surface, dielectric rod waveguide with an integrated phase shifter, tuneable leaky-wave antenna, active reflectarray, and shaped lens antenna with an integrated switched feed array. In these antennas the necessary phase change for antenna elements can be achieved using various electronically tuneable elements, but in our case MEMS are used. Some early results of our investigations are presented.
Proceedings of 2012 5th Global Symposium on Millimeter-Waves, 2012
ABSTRACT In many emerging applications of millimeter waves, electronic focusing and beam steering... more ABSTRACT In many emerging applications of millimeter waves, electronic focusing and beam steering is needed. We present a survey of mm-wave beam steering antennas, where the necessary phase change for antenna elements is achieved using various electronically tuneable elements, e.g. microelectromechanical systems (MEMS), such as tuneable leaky-wave antennas, shaped lens antennas with integrated switched feed array, active reflectarray, tuneable high-impedance surface, and dielectric rod waveguides with integrated phase shifters. Some early results of our own relevant investigations are also presented.
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Papers by A. Raisanen