| 1. |
- Stjernman, Anders, et al.
(författare)
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Multi-Objective Optimization of MIMO Antenna Systems
- 2009
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Ingår i: Antennas and Propagation, 2009. EuCAP 2009. 3rd European Conference on. - 9781424447534 ; , s. 1758 -1762
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Konferensbidrag (refereegranskat)abstract
- This paper discusses the use of multi-objective optimization in the context of designing a dual antenna system for diversity reception or MIMO communication on a mobile platform in the recently released communication band 750-800 MHz. The performance of such systems is highly dependent on the received signal levels and also on the correlation between the signals. Also, from a radio-engineering point of view, there are limitations on the S-parameters of the design. Further, the antennas also need to share space with other devices on the platform, which adds requirements on the size of the antennas. All these aspects often lead to conflicting requirements, which traditionally are dealt with in the optimization by weighting the different requirements into a single requirement. That approach has several disadvantages including that no trade-off discussion between the different requirements can be made. Multi-objective optimization avoids these disadvantages and has the benefit that the decision of optimal design is made by the antenna engineer then all possibilities and limitations are known.
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| 2. |
- Bolin, Thomas, et al.
(författare)
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Two-antenna receive diversity performance in indoor environment
- 2005
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 41:22, s. 1205-1206
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Tidskriftsartikel (refereegranskat)abstract
- Receive diversity gain performance of a two-antenna setup in an office environment is reported. The terminal is handheld in front of the user simulating a data mode scenario while walking around. The dual polarised base station sector antenna is placed at the end of a corridor. The results indicate that experimentally achieved diversity performance is similar to previously predicted theoretical data.
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| 3. |
- Derneryd, Anders, et al.
(författare)
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A 23 GHz sector antenna for point-to-multipoint communications
- 2005
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Ingår i: 18th International Conference on Applied Electromagnetics and Communications, Conference Proceedings. - ZAGREB : KOREMA. ; , s. 297-300
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Konferensbidrag (refereegranskat)abstract
- A broadband and compact antenna concept for a point-to-multipoint communication system at millimeter-wave frequencies is presented. The antenna consists of a rectangular feed waveguide, an H-plane parallel plate horn, an enclosed parabolic reflector section, a radiation slot aperture, and corrugated external baffles. The bandwidth is 2.9 GHz corresponding to a relative bandwidth of 12.6 % at 23 GHz for a return loss better than 10 dB of a prototype. The overall dimensions of the manufactured antenna are 200 mm by 14 7 mm by 50 mm.
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| 4. |
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| 5. |
- Derneryd, Anders, et al.
(författare)
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Application of gain-bandwidth bounds on loaded dipoles
- 2009
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Ingår i: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725. ; 3:6, s. 959-966
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Tidskriftsartikel (refereegranskat)abstract
- Physical limitations based only on antenna volume, form factor and material parameters are applied to electrically small antennas in the form of single dipoles. The upper bound on the gain-bandwidth product is solely determined by the polarisability matrix that characterises the antenna when it is immersed in a uniform applied static field. The polarisability, and hence the bandwidth, is increased by loading the dipole arms close to their ends. The half-power impedance bandwidth is increased from 5 to 13% by moving the coils from the centre to the ends of the dipole arms. The introduction of a stub-matching further improves the bandwidth but the physical limit is not reached. Finally, a dual-resonance dipole antenna is analysed. It is observed that a second resonance hardly reduces the bandwidth of the first resonance if the resonances are separated more than 1.7 times in frequency.
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| 6. |
- Gevorgian, Spartak, 1948, et al.
(författare)
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Tunable Arrangements
- 2007
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates to a tunable microwave/millimeter-wave arrangement comprising a tunable impedance surface. It comprises an Electromagnetic Bandgap Structure (EBG) (Photonic Bandgap Structure) comprising at least one tunable ferroelectric layer (3), at least one first, top, metal layer (1) and at least one second metal layer (2A, 2B). Said first (1) and second metal layers (2A) are disposed on opposite sides of the/a ferroelectric layer (3), and at least the first, top, metal layer (1) is patterned and the dielectric permittivity of the at least one ferroelectric layer (3) is dependent on a DC biasing voltage directly or indirectly applied to first (1) and/or second (2A, 2B) metal layers disposed on different sides of the/a ferroelectric layer.
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| 7. |
- Harrysson, Fredrik, et al.
(författare)
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Dual antenna terminals in an indoor scenario
- 2006
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Ingår i: [Host publication title missing]. - 1550-2252. ; 6, s. 2737-2741
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Konferensbidrag (refereegranskat)abstract
- The performance of two different dual antenna hand-held test mobile terminals has been investigated in a realistic indoor office environment and scenario, with respect to antenna performance, diversity combining and Shannon MIMO channel capacity. Measurements of a 2times2 MIMO channel at 1877.5 MHz (narrowband) were performed using a dual-polarized base station antenna. Analyses show that diversity gains, using ideal selection combining and maximum ratio combining, between 0.7 and 4.6 dB was achieved at the 10% outage probability level. Ideal dual-side beamforming (single branch) gives up to 3.3 dB capacity gain compared to single antenna systems at SNR less than 10 dB, however, decreases with rising SNR. Dual branch MIMO capacity gain is only significant at higher SNR above 10 dB. In addition, horizontal polarization at the base station was found to outperform vertical polarization in this scenario
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| 8. |
- Plicanic, Vanja, et al.
(författare)
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Actual diversity performance of a multiband diversity antenna with hand and head effects
- 2009
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 57:5, s. 1547-1556
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Tidskriftsartikel (refereegranskat)abstract
- Using the metric actual diversity gain (ADG), diversity performance is investigated for a compact mobile terminal prototype with two internal, triple frequency band antennas in four different cases of user interaction. ADG is presented as a preferred alternative to apparent diversity gain and effective diversity gain. Absorption due to user proximity causes degradation and imbalance in mean effective gain of the antennas over the frequency bands, contributing to a degradation in diversity performance. However, user-induced changes in the antenna patterns cause a decrease in correlation in the low frequency band, which facilitates increased diversity gain. The study reveals that a significant net diversity gain, i.e., ADG of 5-8 dB compared to a single antenna prototype, can be achieved using multiband antennas in the proximity of a user, even at low frequencies for antennas with high mutual coupling.
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| 9. |
- Plicanic, Vanja, et al.
(författare)
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Antenna diversity evaluation for mobile terminals
- 2006
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Ingår i: European Space Agency, (Special Publication) ESA SP. - 0379-6566 .- 1609-042X. ; 626 SP
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Konferensbidrag (refereegranskat)abstract
- In this paper we are focusing on the practical, engineering way of evaluating and characterizing the multi-channel antenna solutions on the mobile terminal. Two methods of calculating the parameters, describing the diversity performance, are described and the practical use of the methods in simulations and measurements are presented and evaluated. The time saving aspect of using the scattering parameters is lifted forward but also its limitations. For comparison, a statistical method for calculating Diversity Gain is also presented. This evaluation is performed for two multi-channel antenna solutions with different characteristics for the purpose of characterizing different diversity performances.
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| 10. |
- Plicanic, Vanja, et al.
(författare)
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Channel capacity performance of multi-band dual antenna in proximity of a user
- 2009
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Ingår i: 2009 IEEE International Workshop on Antenna Technology: Small Antennas and Novel Metamaterials (IWAT). - 9781424443956 ; , s. 41402-41402
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Konferensbidrag (refereegranskat)abstract
- This paper presents an evaluation of single input single output (SISO), single input multiple output (SIMO) and multiple input multiple output (MIMO) channel capacities for a dual antenna prototype in proximity of a user. The dual antenna prototype mimics today’s small mobile phone design in size and in comprising internal, compact, multi-band antennas. Four different user cases are evaluated by measuring the antenna radiation performance for each of the different interactions between a phantom user and the antenna. Measurements of a single antenna prototype with user are also performed for comparisons between the SISO case and the SIMO/MIMO cases. Depending on the user interaction case, the MIMO capacity of the prototype is between 40-90% at 850 MHz and 60-80% at 2100 MHz higher than the SISO performance of the single antenna prototype or the best antenna on the dual antenna prototype.
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