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- Rahiminejad, Sofia, 1987, et al.
(författare)
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Micromachined Ridge Gap Waveguide and Resonator for Millimeter-Wave Applications
- 2012
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Ingår i: Sensors and Actuators, A: Physical. - : Elsevier BV. - 0924-4247 .- 1873-3069. ; 186, s. 264-269
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Tidskriftsartikel (refereegranskat)abstract
- The ridge gap waveguide is a fundamentally new high-frequency waveguide. It does not need any electrical contact between the split blocks which gives it an advantage compared to the rectangular waveguide which is the standard today. These waveguides are conventionally fabricated by milling, although above 100 GHz milling is not adequate anymore. MEMS technology on the other hand, can offer high-precision fabrication and thus opens the path for new types of high-frequency components. In this paper both a ridge gap waveguide and a ridge gap resonator have been fabricated for the frequencies 220–325 GHz using MEMS technology. Support packages have been designed to enable device measurements. Simulations show that the reflection coefficient for the ridge gap waveguide is below −15 dB between 240 and 340 GHz. Two resonance peaks were measured at the frequencies 234 GHz and 284 GHz for the ridge gap resonator with unloaded Q-values of 336 and 527 respectively. Both the waveguide and resonator have the potential to obtain similar performances as the rectangular waveguide without strict requirement on electrical contact, allowing simplified fabrication and assembly technique.
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| 6. |
- Sorkherizi, M. S., et al.
(författare)
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Design of integrated diplexer-power divider
- 2016
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509006984 ; 2016-August
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Konferensbidrag (refereegranskat)abstract
- A new configuration is introduced to integrate diplexers and power dividers. The proposed configuration is based on coupling matrix. The design of the lumped element network is based on addition of an extra term to the conventional error function of the coupling matrix to decouple the two ports of the power divider. An optimized lumped element network is implemented successfully on an EBG based guiding technology known as ridge gap waveguide. The optimization of the physical structure is done efficiently by dividing the diplexer-power divider into many sub-circuits and analyzing the corrected delay response of them.
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| 7. |
- Kildal, Per-Simon, 1951, et al.
(författare)
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Modern Antenna Technologies Stimulated by the Arecibo Radio Telescope Upgrade Project 1984-1997
- 2016
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Ingår i: 2016 Ieee Antennas and Propagation Society International Symposium. - 1947-1491. - 9781509028863 ; , s. 379-380
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Konferensbidrag (refereegranskat)abstract
- The world's largest single-reflector radio telescope is located in Arecibo. Its Gregorian dual-reflector feed was inaugurated in 1997, representing an enormous improvement in terms of bandwidth (limited by that of a wide-angle corrugated horn) and aperture efficiency compared to using the previous line feeds of about 1% bandwidth. The inauguration was preceded by an upgrading project of more than 10 years duration, during which author of this paper was stimulated to get ideas of several other technologies that were further developed the decades thereafter. The present paper gives an overview of these technologies, and how they are related to the upgrade project: the Comhat antenna (a hat-fed reflector) originating from an initial theoretical model of the line feeds, semi-analytical reflector synthesis by ray tracing, wideband constant widebeamwidth feed for paraboloids, canonical soft and hard surfaces, and gap waveguides.
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| 8. |
- Carlsson, Jan, et al.
(författare)
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Diversity gains in random line of sight and rich isotropic multipath environment
- 2012
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Ingår i: LAPC 2012 - 2012 Loughborough Antennas and Propagation Conference.
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Konferensbidrag (refereegranskat)abstract
- Antenna diversity gain for theoretical as well as measured antennas is studied in two extreme environments, the rich isotropic multipath environment (RIMP) and the random line-of-sight environment. The RIMP diversity gain was previously defined based on improved fading performance, here we equivalently consider it as a metric for the cumulative improvement of the 1% worst users randomly distributed in the RIMP environment. Similarly, we consider the diversity gain in the random line-of-sight environment to be the performance improvement of the 1% of the users which receives the weakest signal relative to a theoretical Rayleigh distribution of the signal levels among the users. The random line-of-sight environment is regarded as being caused by the statistics of an ensemble of users (or terminals) with arbitrary 3D orientations. © 2012 IEEE.
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| 9. |
- Kildal, Per-Simon, 1951, et al.
(författare)
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OTA Testing of 3G-5G Devices with MIMO: From Anechoic Chambers to Reverberation Chambers and ... Back Again?
- 2017
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Ingår i: IEEE Antennas and Propagation Society International Symposium. - 1522-3965. - 9781538632840 ; , s. 1697-1698
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Konferensbidrag (refereegranskat)abstract
- The present paper describes the paradigm shift in OTA testing that came with the arrival of the 4G wireless system. The testing was previously mainly done in anechoic Line-Of-Sight (LOS) environments, and now in 4G it is done in reverberation chambers, emulating Rich Isotropic MultiPath (RIMP). Now we are preparing for the 5G wireless system, which is expected to have mm-wave antennas with steerable lobes. This will require OTA testing in anechoic environments again, but with an emphasis on system measurements, i.e. data rate throughput for an arbitrary location and orientation of the user, referred to as Random-LOS.
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| 10. |
- Sibille, Alain, et al.
(författare)
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Guest Editorial AWPL Special Cluster on Impact of User-Related Randomness on Antennas and Channels
- 2017
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757 .- 1536-1225. ; 16, s. 1840-1842
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The papers in this special issue focus on the impact of user-related randomness on antennas and channels. In the early days of telecommunications, most antennas were considered as fixed installations, and their performance was determined in terms of their directivity and radiations patterns when the polarizations of the antennas on the transmitting and receiving sides were aligned. With the birth of satellite communications, there soon became a need for reusing the frequencies by polarization multiplexing, resulting in dual polarized systems with an even stricter requirement to alignment in order to avoid interference between the two communication channels. Furthermore, mobile communications resulted in random channels owing to both fast Rayleigh fading and slow shadow fading. Nowadays, wireless devices and base stations/access points are used more and more in hugely differing contexts and environments for terminals. The papers in this issue have been prepared in this context, the aim being to help make better known the issues raised above from the antennas and propagation community and to contribute to foster research and development in this area.
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