| 1. |
- Stjernman, Anders, et al.
(författare)
-
Multi-Objective Optimization of MIMO Antenna Systems
- 2009
-
Ingår i: Antennas and Propagation, 2009. EuCAP 2009. 3rd European Conference on. - 9781424447534 ; , s. 1758 -1762
-
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.
|
|
| 2. |
- Bolin, Thomas, et al.
(författare)
-
Two-antenna receive diversity performance in indoor environment
- 2005
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 41:22, s. 1205-1206
-
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.
|
|
| 3. |
- Derneryd, Anders, et al.
(författare)
-
A 23 GHz sector antenna for point-to-multipoint communications
- 2005
-
Ingår i: 18th International Conference on Applied Electromagnetics and Communications, Conference Proceedings. - ZAGREB : KOREMA. ; , s. 297-300
-
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.
|
|
| 4. |
- Derneryd, Anders, et al.
(författare)
-
Antenna signal correlation and its relation to the impedance matrix
- 2004
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 40:7, s. 401-402
-
Tidskriftsartikel (refereegranskat)abstract
- Theory is presented that extends the analysis to signal correlation between any antennas in an array of elements. It is generalised to include non-identical elements and arbitrary load termination of passive antenna ports. The method is related to the power balance concept and based on the antenna impedance matrix.
|
|
| 5. |
|
|
| 6. |
- Derneryd, Anders, et al.
(författare)
-
Application of gain-bandwidth bounds on loaded dipoles
- 2009
-
Ingår i: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725. ; 3:6, s. 959-966
-
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.
|
|
| 7. |
- Derneryd, Anders, et al.
(författare)
-
Mobile and terminal antennas
- 2003
-
Ingår i: Antenn 03. Nordic Antenna Symposium. Conference Proceedings. ; , s. 37-38
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This project deals with the analysis of antennas for mobiles and terminals in the form of a patch element on a grounded substrate. A special case of this antenna element is the PIFA-element. The analysis is based on the propagator method, a vector generalisation of the transmission line theory, that has been extended to the analysis of surface waves in inhomogeneous permittivity profiles. Analyses of combined antenna radiation pattern and propagation channel characteristics have been initiated in order to demonstrate the performance advantage of exploiting two-antenna signals on a terminal for diversity or interference suppression. A generic two-antenna terminal is presented in this paper which improves capacity on reception. Signal correlation coefficients that depend on the mutual coupling are calculated.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Derneryd, Anders, et al.
(författare)
-
Signal correlation including antenna coupling
- 2004
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 40:3, s. 157-159
-
Tidskriftsartikel (refereegranskat)abstract
- Mutual coupling effects between antenna elements on signal correlation are reported. A simple expression is derived to compute the correlation coefficient from the far-field radiation patterns including the characteristics of the propagation environment and the terminating impedance. It is shown that the mutual coupling between closely spatially separated dipoles call lead to increased signal decorrelation.
|
|
| 11. |
- Engström, Ulrika, et al.
(författare)
-
Multi-beam antennas in a PMP system : An up-link carrier to interference ratio performance evaluation
- 2001
-
Ingår i: IEEE 54TH VEHICULAR TECHNOLOGY CONFERENCE, VTC FALL 2001. - 0780370058 ; , s. 338-342
-
Konferensbidrag (refereegranskat)abstract
- The performed study is an up-link carrier-to-interference (C/I) performance evaluation of narrow multi-beam and wide sector-beam node antennas in a PMP system. It is shown that the introduction of three-beam node antennas improves up-link C/I with 5 dB compared with wide-beam sector antenna. The replacement of wide-beam antennas can be made on a sector by sector basis. Simulations have shown that it is possible to get significant interference improvement in a 5x3-hub network by replacing 20% of the wide-beam antennas with multi-beam antennas.
|
|
| 12. |
- Gevorgian, Spartak, 1948, et al.
(författare)
-
Tunable arrangements
- 2011
-
Patent (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.
|
|
| 13. |
- Gevorgian, Spartak, 1948, et al.
(författare)
-
Tunable Arrangements
- 2007
-
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.
|
|
| 14. |
- Harrysson, Fredrik, et al.
(författare)
-
Dual antenna terminals in an indoor scenario
- 2006
-
Ingår i: [Host publication title missing]. - 1550-2252. ; 6, s. 2737-2741
-
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
|
|
| 15. |
- Harrysson, Fredrik, et al.
(författare)
-
Evaluation of user hand and body impact on multiple antenna handset
- 2010
-
Ingår i: [Host publication title missing]. - 1522-3965 .- 1947-1491. - 9781424449675
-
Konferensbidrag (refereegranskat)abstract
- From our experimental investigation of multiple-antenna performance and user impact of a realistic mobile terminal setup, we find that apart from the important loss of efficiency due to the user hand, the impact on the individual antennna elements and the directional impact of the user body shadowing have quite small influence on the diversity and capacity performance. It is found that the top and bottom placement of antennas within the handset case are the most efficient to be used with up to two antenna elements. There are, however, significant diversity and capacity gain that can be explored by using four distributed antennas even if only two radio chains are available through hybrid selection and combining schemes. It was also found that the practical method of choosing antennas based on signal power for 2 branch MIMO with 4 available handset antennas, performs well compared to the optimal solution.
|
|
| 16. |
- Jamaly, Nima, 1979, et al.
(författare)
-
Analysis of Antenna Pattern Overlap Matrix in Correlated Nonuniform Multipath Environments
- 2013
-
Ingår i: Proceedings of the 7th European Conference on Antennas and Propagation. - 2164-3342. - 9788890701832 ; , s. 2113-2117
-
Konferensbidrag (refereegranskat)abstract
- In this paper the covariance matrix of received voltage signals across ports of a multiport antenna in correlated multipath environments is formulated. This eventually leads to some expressions for mean effective gain and directivity in these environments, which to our best knowledge has not been addressed before. The notion of pattern overlap matrix is utilized to coin correlated pattern overlap matrix. We show the crucial role of the latter parameter in general correlated multipath environments.
|
|
| 17. |
- Jamaly, Nima, 1979, et al.
(författare)
-
Effects of coupling and overspeeding on performance of predictor antenna systems in wireless moving relays
- 2019
-
Ingår i: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 13:3, s. 367-372
-
Tidskriftsartikel (refereegranskat)abstract
- Using predictor antenna systems for modern wireless moving relays and base stations on top of vehicles such as buses, trains etc. proves to be a reliable approach for collecting channel state information to such fast moving nodes. Recently, it has been shown that coupling between different ports of a multiport antenna system used as a part of a predictor system can reduce the prediction performance. In this study, by integrating position and velocity vectors in the channel covariance matrix as seen at the antenna ports in a rich multipath environment, the authors quantify the impact of antenna coupling on prediction performance. Moreover, practically these predictor systems are designed for a certain target velocity. They further quantify the adverse effect of velocities, different from the target velocity, on prediction performance. In case open-circuit decoupling is necessary, the sensitivity of the predictor antenna system performance with respect to the accuracy of the input network parameters is disclosed.
|
|
| 18. |
- Jamaly, Nima, 1979, et al.
(författare)
-
Fast Measurement of Antenna Pattern Overlap Matrix in Reverberation Chamber
- 2013
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 49:5, s. 318-319
-
Tidskriftsartikel (refereegranskat)abstract
- Presented is a fast way for the measurement of the pattern overlap matrix in an arbitrary multi-port antenna system by a reverberation chamber. This parameter is central for calculation of the spatial correlation between different elements with arbitrary terminations. To the authors' knowledge, this is the fastest method for the measurement of the pattern overlap matrix in a lossy structure.
|
|
| 19. |
|
|
| 20. |
- Jamaly, Nima, 1979, et al.
(författare)
-
Spatial Diversity Performance of Multiport Antennas in the Presence of a Butler Network
- 2013
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 61:11, s. 5697-5705
-
Tidskriftsartikel (refereegranskat)abstract
- The main concern of this paper is to study the presence of a cascaded Butler network in diversity antenna systems. The advantages of a cascaded Butler network in 2Dmultipath environments have been already shown. These advantages are limited to either correlated or nonuniform multipath environments with a line-of-sight component. In the frame of this paper, for the first time, we show a further advantage of a cascaded Butler network in 3D multipath environments, including the effects of coupling. This advantage is associated with an improved convergence in received signals’ covariance matrix in a multipath environment wherein the number of independent incoming waves is limited, i.e., non-rich multipath environment. For this purpose, we use a simulation tool in which a multipath scenario with certain number of incoming waves is emulated and some selected multiport antennas are exposed to it. Afterwards, the simulated random received signals are used to yield different performance metrics like spatial correlation. This advantage achieves considerable practical interest since a typical actual multipath scenario is most likely a non-rich multipath environment.
|
|
| 21. |
- Kristensson, Gerhard, et al.
(författare)
-
Radiation efficiency and surface waves for patch antennas on inhomogeneous substrat
- 2001
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this paper the surface wave characteristics, as well as the radiation efficiency and the directivity of a patch antenna, with a given current distribution, located on top of an inhomogeneous, isotropic substrate are calculated. The substrate is infinite in the lateral directions and inhomogeneous with respect to the height coordinate. The surface waves in the substrate are analyzed using the propagator technique and residue calculus. The propagators and the residues are found by solving two sets of systems of ordinary differential equations (ODEs). Several dispersion curves of the surface waves for inhomogeneous substrates are calculated. The radiation efficiency and the directivity are compared with the corresponding quantities of a printed antenna on a homogenized substrate. Moreover, some alternative ways of calculating the reflection dyadic of an inhomogeneous substrate are presented in a series of appendices.
|
|
| 22. |
- Kristensson, Gerhard, et al.
(författare)
-
Radiation efficiency and surface waves for patch antennas on inhomogeneous substrates
- 2003
-
Ingår i: IEE Proceedings - Microwaves Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1350-2417. ; 150:6, s. 477-483
-
Tidskriftsartikel (refereegranskat)abstract
- Surface wave characteristics and radiation efficiency are calculated for a patch antenna with a given current distribution and located on top of an inhomogeneous, isotropic substrate. The substrate is infinite in the lateral directions and inhomogeneous with respect to the height coordinate. The surface waves in the substrate are analysed using the propagator technique and residue calculus. The propagators and the residues are found by solving two sets of systems of ordinary differential equations (ODEs). Several dispersion curves of the surface waves for inhomogeneous substrates are calculated. The radiation efficiency is compared with the corresponding quantities of a printed antenna on a homogeneous substrate.
|
|
| 23. |
|
|
| 24. |
- Lundh, Ros-Marie, et al.
(författare)
-
Processing of RF-MEMS Switches
- 2004
-
Ingår i: MEMSWAVE, June 30-July 2, 2004, Uppsala, Sweden.
-
Konferensbidrag (refereegranskat)
|
|
| 25. |
- Plicanic, Vanja, et al.
(författare)
-
Actual diversity performance of a multiband diversity antenna with hand and head effects
- 2009
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 57:5, s. 1547-1556
-
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.
|
|
| 26. |
- Plicanic, Vanja, et al.
(författare)
-
Antenna diversity evaluation for mobile terminals
- 2006
-
Ingår i: European Space Agency, (Special Publication) ESA SP. - 0379-6566 .- 1609-042X. ; 626 SP
-
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.
|
|
| 27. |
- Plicanic, Vanja, et al.
(författare)
-
Channel capacity performance of multi-band dual antenna in proximity of a user
- 2009
-
Ingår i: 2009 IEEE International Workshop on Antenna Technology: Small Antennas and Novel Metamaterials (IWAT). - 9781424443956 ; , s. 41402-41402
-
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.
|
|
| 28. |
- Plicanic, Vanja, et al.
(författare)
-
On MIMO capacity of a dual multiband antenna prototype with user interactions
- 2008
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)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.
|
|
| 29. |
|
|
| 30. |
- Uz Zaman, Ashraf, 1975, et al.
(författare)
-
Dual polarised microstrip patch antenna with high port isolation
- 2007
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 43:10, s. 551-552
-
Tidskriftsartikel (refereegranskat)abstract
- A probe fed stacked microstrip patch antenna for operation in dual polarisation mode is proposed. A slot loaded lower patch is presented to improve isolation between the two polarisation ports. Simulations and measurements show two linear polarisations with an isolation of more than 30 dB within the band 2.5-2.7 GHz. A return loss of -10 dB is achieved within the above-mentioned bandwidth for the proposed antenna. The radiation pattern for the antenna is similar to that of a conventional microstrip antenna and the measured cross-polar level is 16.5 dB below the peak co-polar level within the band 2.5-2.7 GHz.
|
|
| 31. |
|
|
| 32. |
- Ying, Zhinong, et al.
(författare)
-
Diversity antenna terminal evaluation
- 2005
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1947-1491 .- 1522-3965. - 0780388836 ; 2 A, s. 375-378
-
Konferensbidrag (refereegranskat)abstract
- Simulated and measured correlation and diversity performance for a couple of two-antenna concepts are presented. The results indicate that the three-dimensional isotropic incident field is a good reference case to evaluate diversity performance in a multi-antenna application.
|
|
