| 1. |
- Capdevila, S., et al.
(författare)
-
RFID based probes for EM-field measurements
- 2009
-
Ingår i: European Conference on Antennas and Propagation, EuCAP 2009, Proceedings. - : IEEE. - 9783000245732 ; , s. 2787-2790
-
Konferensbidrag (refereegranskat)abstract
- In this paper the use of RFID for EM field measurement is studied. A novel RFID antenna with high tuning capabilities is presented and measured, and it is used in combination with several RFID IC to measure the EM field along the H-plane of a horn antenna. A calibration procedure for the non-linear effects in RFID IC is introduced and used to correct the measured fields.
|
|
| 2. |
- Geterud, Erik G, 1978, et al.
(författare)
-
Simulation of a lens antenna using a parallelized version of an FDTD simulator
- 2009
-
Ingår i: 2009 3rd European Conference on Antennas and Propagation, Vols 1-6. - : IEEE conference proceedings. - 9781424447534 - 9783000245732 ; , s. 3337-3341
-
Konferensbidrag (refereegranskat)abstract
- This article is evaluating parallel processing in electromagnetic simulations for computationally demanding application, using developed FDTD code. A waveguide lens antenna which is complex and large in terms of wavelengths has been simulated and a prototype has been fabricated and measured. Simulated and measured radiation patterns are compared and showing good agreement. The approach of using parallel version of Quick Wave-3D software on a popular multi-CPU shared-memory computer has been found suitable for demanding simulations of complex structures.
|
|
| 3. |
- Gómez Calero, Carlos, 1981, et al.
(författare)
-
Effect of Mutual Coupling and Human Body on MIMO Performances
- 2009
-
Ingår i: 2009 Proceedings of the Third European Conference on Antenna and Propagation, EuCAP. - 9783000245732 ; , s. 1042-1046
-
Konferensbidrag (refereegranskat)abstract
- In the last recent years, MIMO (Multiple Input and Multiple Output) system have been studied and developed by many researchers. These systems allow an increase in the binary data rate and the improvement of the quality of received signals, due to spatial multiplexing and space-time diversity. The performances of MIMO systems depend on the antenna design. In this paper, we focused on the importance of mutual coupling and human effect on the MIMO performances. Three different types of antennas have been designed: monopoles, cross-polarized dipoles and a Planar Inverted-F Antennas (PIFAs). The antennas work at 2.45 GHz for WLAN applications and also PIFAs work at GSM 1800 and 5.4 GHz for the other WLAN band. The results show the importance of spacing among radiating elements due to the mutual coupling and measurements in a reverberation chamber comparing the effect of the user's head.
|
|
| 4. |
- Halim, Humam, et al.
(författare)
-
Evaluation of a Near Field Scanner for TRP and Radiation Pattern Measurements of GSM Mobile Phones
- 2009
-
Ingår i: 3rd European Conference on Antennas and Propagation, 2009. EuCAP 2009.. - Berlin : EUCAP2009. - 9781424447534 - 9783000245732 ; , s. 2207-2211
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper a new tool for estimation of the radio performance of terminal antennas in terms of Total Radiated Power, TRP is tested and evaluated. The tool is known as Lab Express and is developed by the Canadian company EMSCAN. The results from measurements performed with the Lab Express are compared with of the radiation patterns and total radiated power (TRP) estimates, measured with a CTIA approved Satimo SG24 chamber. The TRP and radiation pattern measurements are performed on 10 commercially available mobile phones at GSM 900 and GSM 1800 frequency bands. The dependency of the measured TRP on the positioning of the mobile phone on EMSCAN is also tested. Our results indicate that the TRP measured with Lab Express is well correlated with the results obtained from the Satimo SG24 chamber even though the Lab Express equipment seem to over estimate the TRP with on average about 4dB at 900MHz and about 1.3dB at 1800MHz.
|
|
| 5. |
- Jacobsson, Per, 1977, et al.
(författare)
-
Shape Optimization of Conformal Array Antennas
- 2009
-
Ingår i: European Conference on Antennas and Propagation. ; , s. 2713-2717, s. 2713-2717
-
Konferensbidrag (refereegranskat)abstract
- We present a shape optimization method for the minimization of the activereflection coefficient for conformal array antennas. Our formulation is based onthe continuum form of Maxwell's equations, where the gradient of the goalfunction is expressed in terms of the solution to the original field problem andthe solution to an adjoint field problem. The computational work for the goalfunction and its gradient amounts to the computation of the scattering matrix,which makes our method independent of the number of degrees of freedom used toparameterize the geometry. In addition, the field solver is decoupled from theoptimization process, which offers great freedom in the choice of field solver.The method is tested in two dimensions for an array antenna that conforms to acircular cylinder. An optimum is found in approximately 10 iterations when fourdegrees of freedoms are used to describe the antenna geometry and inapproximately 30 iterations when 40 degrees of freedoms are used.
|
|
| 6. |
- Jamaly, Nima, 1979, et al.
(författare)
-
Study of Excitation on Beam Ports versus Element Ports in Performance Evaluation of Diversity and MIMO Arrays
- 2009
-
Ingår i: 3rd European Conference on Antennas and Propagation, EuCAP 2009; Berlin; Germany; 23 March 2009 through 27 March 2009. - 9783000245732 ; , s. 1753-1757
-
Konferensbidrag (refereegranskat)abstract
- The main concern of the current communication is to elicit the influences of beam-forming upon different Multiple- Input Multiple-Output (MIMO) parameters in a rich scattering environment. A detailed study of desired parameters is presented with particular stress on total radiation efficiencies observed on Element ports and Beam ports. Measurements are performed in a Reverberation Chamber (RC). The results illustrate that performance as viewed through Element and Beam ports are, in general, equal. Hence, they confirm that in a rich and isotropic scattering environment, beam-forming technique does not prove beneficial. They also demonstrate that as long as received radiation power is preserved, the shapes of the elements' patterns are irrelevant.
|
|
| 7. |
- Maci, Stefano, 1961, et al.
(författare)
-
Dispersion characteristics of a metamaterial-based parallel plate ridge waveguides
- 2009
-
Ingår i: 3rd European Conference on Antennas and Propagation, EuCAP 2009; Berlin; Germany; 23 March 2009 through 27 March 2009. - 9783000245732 ; , s. 1675-1678
-
Konferensbidrag (refereegranskat)abstract
- This paper presents an approximate analytical analysis of the quasi-TEM dominant mode in a parallel plate metamaterial-based waveguide. This waveguide is constituted by a fakir's bed plate interrupted by a metal strip, and covered by a metallic plate. This structure is simple to manufacture, especially at millimetre and sub-millimetre wave frequencies.
|
|
| 8. |
- Orlenius, Charlie, 1976, et al.
(författare)
-
Repeatable performance measurements of MIMO systems in connected reverberation chambers with control of channel richness
- 2009
-
Ingår i: Eucap 2009, 3rd European Conference on Antennas and Propagation - 23-27 March 2009 in Berlin, Germany. - 9783000245732 ; , s. 1086-1089
-
Konferensbidrag (refereegranskat)abstract
- A straightforward, fast, and repeatable procedure for measuring the system performance of the antennas in a MIMO system is presented. Due to the use of two connected reverberation chambers, the so called keyhole effect is observed and can be controlled. The method is possible to use for performance measurements of complete MIMO systems, and the present paper lays out the basics for making this possible.
|
|
| 9. |
- Persson, Patrik, et al.
(författare)
-
Design and evaluation of a 2 x 2 MIMO repeater
- 2009
-
Ingår i: European Conference on Antennas and Propagation, EuCAP 2009, Proceedings. - 9783000245732 ; , s. 1509-1512
-
Konferensbidrag (refereegranskat)abstract
- In this paper the design and measurement-based evaluation of an amplify-and-forward 2 x 2 MEMO repeater is presented. During the design phase, simulations were made to study different scenarios and repeater parameter settings. The evaluation of the repeater was made using field trials in Kista, Stockholm, Sweden. Three scenarios were considered; coverage, outdoor-to-indoor, and LOS MEMO rank enhancement. The overall results showed good improvement in received signal strength, ranging from only a few dB up to 25 dB depending on the particular measurement scenario. Moreover, the concept of repeater-aided rank enhancement in LOS also showed good results.
|
|
| 10. |
- Rajo, Eva, 1972, et al.
(författare)
-
Cut-off bandwidth of metamaterial-based parallel plate gap waveguide with one textured metal pin surface
- 2009
-
Ingår i: Eucap 2009, 3rd European Conference on Antennas and Propagation - 23-27 March 2009 in Berlin, Germany. - 9783000245732 ; , s. 33-36
-
Konferensbidrag (refereegranskat)abstract
- This work explores the possibilities of creating stop bands (or bandgaps) for TEM mode in parallel plate waveguides by using artificial surfaces in one of the plates. Particularly, as artificial surface a textured periodic surface made of metal pins has been selected. The present paper reports a parametric study of the "Fakir's bed of nails" structure in terms of the size of the achieved bandgap when the structure is placed within a parallel plate waveguide. Bandwidths larger than 2:1 are seen to be possible. The proposed structure could be used for the design of the new type of waveguides named gap waveguides.
|
|
| 11. |
- Roqueta, G., et al.
(författare)
-
A novel compact UHF wideband antenna for near field electrical characterization of Steel Fiber Reinforced Concrete
- 2009
-
Ingår i: European Conference on Antennas and Propagation, EuCAP 2009, Proceedings. - 9783000245732 ; , s. 2393-2397
-
Konferensbidrag (refereegranskat)abstract
- A novel, electrically small, UHF (350 MHz-750 MHz) microstrip slot antenna is presented. The antenna is designed for the characterization of Steel Fiber Reinforced Concrete (SFRC) segments. The antenna consists on a three layer structure headed by the slot ground plane, followed by the feeding microstrip in the central layer with some resistive loading for bandwidth enhancement purposes; finally on the bottom layer a strip line reflector is positioned to provide a unidirectional radiation pattern, required for harsh environments. The whole design has been optimized in front of SFRC for maximum impedance bandwidth. Input impedance and radiation pattern are studied both theoretically and experimentally, and some laboratory measurements have been done on real SFRC specimens. Satisfactory results for the fiber density of SFRC are presented.
|
|
| 12. |
- Sipus, Zvonimir, 1964, et al.
(författare)
-
Local wave Green's functions of parallel plate metamaterial-based gap waveguides with one hard wall
- 2009
-
Ingår i: 3rd European Conference on Antennas and Propagation, EuCAP 2009; Berlin; Germany; 23 March 2009 through 27 March 2009. - 9783000245732 ; , s. 37-40
-
Konferensbidrag (refereegranskat)abstract
- The purpose of the presented paper is to give the derivation of the Green's functions of oversized waveguides with one hard wall. Two different realizations of the hard wall were considered: idealized PEC/PMC model and the corrugated hard surface. The applied analysis method avoids the complexity of the Floquet mode approach by using appropriate asymptotic boundary conditions for the observed periodic structure. This is possible because the period of the used periodic structures is very small compared to the wavelength. The developed Green's functions have poles corresponding to surface wave modes and waveguide modes, and their properties are determined by considering the pole distribution. We have also developed a program that calculates the electromagnetic field distribution inside the considered waveguides. The computed results are compared with the results obtained with the general electromagnetic solver, and the agreement is very good.
|
|
| 13. |
- Skobelev, Sergei, 1953, et al.
(författare)
-
Analysis of global eigenmodes in an oversized rectangular waveguide with a hard surface on one broad wall for planar slot array antenna applications
- 2009
-
Ingår i: Eucap 2009, 3rd European Conference on Antennas and Propagation - 23-27 March 2009 in Berlin, Germany. - 9783000245732 ; , s. 41-44
-
Konferensbidrag (refereegranskat)abstract
- The problem of determining the eigenmodes of a rectangular waveguide with one broad hard wall formed by longitudinal corrugations with grooves filled with dielectric is considered. The dispersion equation is derived on the basis of using the asymptotic boundary conditions for corrugated surfaces. It is shown analytically that if the groove depth is equal to the value 0.25λ/ (ε-1)1/2 corresponding to the hard wall condition, the TE eigenmode spectrum of the waveguide comprises an infinite set of degenerated quasi-TEM modes with different transverse propagation constants and identical longitudinal propagation constants equal to the wavenumber k. Such solutions are important for understanding the local waves appearing along ridges in such waveguides, that has inspired to the invention of new so-called gap waveguides.
|
|
| 14. |
- Wolfgang, Andreas, 1977, et al.
(författare)
-
Advanced Repeaters in Cellular Communication Systems
- 2009
-
Ingår i: 3rd European Conference on Antennas and Propagation, EuCAP 2009; Berlin; Germany; 23 March 2009 through 27 March 2009. - 9783000245732 ; , s. 1504-1508
-
Konferensbidrag (refereegranskat)abstract
- A repeater can be used in a wireless link to improve the Signal-to-Noise Ratio (SNR) at the receiver. However, if the transmitter and the receiver use multiple antennas a repeater may serve additional purposes. In this paper we particularly investigate the effect of repeaters on the singular values of the Multiple-Input Multiple-Output (MIMO) channel matrix. Furthermore the effect of repeaters in a cellular system, the interdependence of antenna array design, and system aspects such as scheduling are highlighted.
|
|
