| 1. |
|
|
| 2. |
- Anjos, Eduardo V.P., et al.
(författare)
-
FORMAT: A Reconfigurable Tile-Based Antenna Array System for 5G and 6G Millimeter-Wave Testbeds
- 2022
-
Ingår i: IEEE Systems Journal. - 1932-8184 .- 1937-9234. ; In Press
-
Tidskriftsartikel (refereegranskat)abstract
- This article introduces the FORMAT array, a reconfigurable millimeter-wave antenna array platform based on antenna tiles. FORMAT stands for Flexible Organization and Reconfiguration of Millimeter-wave Antenna Tiles, which is a unique hardware solution aiming to implement and demonstrate a variety of antenna array concepts, as well as different array architectures and configurations from the same basic module, providing even benchmark between different solutions and thus valuable insights into fifth-generation (5G) and beyond-5G antenna systems. The combination of a minimum-sized tile with 3D-printed frame parts enables antenna arrays of a variety of sizes, allows multiple beamforming architectures, and a range of different antenna element positioning in the array. The hardware implementation is thoroughly described, with a few different array assemblies being manufactured and measured, validating their antenna performance with over-the-air measurements. Finally, using FORMAT hardware as both base station and user equipment, a 5-m wireless communication link was set up, achieving 4.8 Gbps downlink speed with QAM64 modulation.
|
|
| 3. |
- Fager, Christian, 1974, et al.
(författare)
-
IC Design Aspects for 5G mm-Wave Systems
- 2020
-
Ingår i: 2020 50TH EUROPEAN MICROWAVE CONFERENCE (EUMC). - 2325-0305. - 9782874870590 ; , s. 870-871
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 4. |
- Aliakbari Abar, Hanieh, et al.
(författare)
-
79 GHz multilayer series-fed patch antenna array with stacked micro-via loading
- 2022
-
Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757. ; 21:10, s. 1990-1994
-
Tidskriftsartikel (refereegranskat)abstract
- A wideband compact series-fed patch subarray is proposed for 79 GHz multiple-input multiple-output (MIMO) radar. The proposed subarray is, for the first time, loaded with stacked micro-vias (SMVs). Two sets of patches in the subarray are fed 180-degrees out-of-phase. A low-cost, high-resolution multilayer PCB technology, called “Any-Layer PCB”, is used to implement the SMVs, which cannot be done by standard HDI PCB technology. Moreover, the technology supports small SMVs on different layers, hence thick machine-drilled vias can be avoided. For comparison, a series-fed patch subarray with no SMV loading is designed. It is shown that SMV loading facilitates a larger overlap of the impedance and gain bandwidths, leading to a larger operating bandwidth. The measured 10 dB impedance and 3 dB gain bandwidths are 15% and 9.6%, respectively. The sidelobe suppression is above 12.9 dB, and the maximum array gain is 12.67 dBi at 79.1 GHz. This subarray is suitable for MIMO radar, as its width is around 1/2-wavelength and the SMVs around it mitigate the crosstalk between the transmitting and receiving arrays.
|
|
| 5. |
- Anjos, Eduardo V. P., et al.
(författare)
-
A 5G Active Antenna Tile and its Characterization in a Reverberation Chamber
- 2020
-
Ingår i: 2020 14TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP 2020). - 2164-3342.
-
Konferensbidrag (refereegranskat)abstract
- This work presents a 5G active antenna tile system, enabling the flexible construction of hybrid beamforming (HBF) arrays. The proposed tile was fabricated using a standard PCB manufacturing process and to validate its performance. Using a Reverberation Chamber (RC), the tile was measured in both Tx and Rx mode, achieving up to 1.6 GHz in bandwidth around a central frequency of 27.8 GHz.
|
|
| 6. |
- Kupresak, Mario, et al.
(författare)
-
Hydrodynamic approach for deep-nanometer scale topologies: Analysis of metallic shell
- 2021
-
Ingår i: 2020 International Symposium on Antennas and Propagation, ISAP 2020. ; , s. 269-270
-
Konferensbidrag (refereegranskat)abstract
- In order to describe light-matter interaction at deep-nanometer scale, which is governed by nonclassical phenomena, a semiclassical hydrodynamic model with additional boundary conditions has been introduced. This model investigates the motion of the charged gas in metals, characterized by nonlocal material parameters. Based on different treatments of the nonlocality, several hydrodynamic models have been proposed. This work employs the hard wall hydrodynamic model (HW-HDM) and the quantum hydrodynamic model (Q-HDM). The study is performed for the mode structure (natural modes) of a spherical metallic nanoshell, supplemented by the plane wave response of the system. It is shown that the main transverse resonances of HW-HDM and Q-HDM experience nearly identical blueshifts in comparison to the classical resonances. The corresponding longitudinal resonances show noticeable spectrum shifts.
|
|
| 7. |
- Kupresak, Mario, et al.
(författare)
-
Nonlocal Response of Plasmonic Nanostructures Excited by Dipole Emitters
- 2021
-
Ingår i: Proceedings Elmar - International Symposium Electronics in Marine. - 1334-2630. ; 2021-September, s. 25-28
-
Konferensbidrag (refereegranskat)abstract
- The interaction between light and plasmonic structures at the deep-nanometer scale, which is essentially governed by nonclassical effects, has been increasingly investigated by the hydrodynamic model. Several hydrodynamic models have been introduced, in order to describe the motion of the free electron gas in metals. In this work, by employing the hard wall hydrodynamic model (HW-HDM) and the quantum hydrodynamic model (Q-HDM), the nonlocal response of an isolated metallic nanoparticle, excited by a dipole emitter, is investigated. The analysis is performed for the local density of states of an emitter coupled with a spherical nanoparticle, which may be treated analytically. Both radial and tangential emitters are studied, while varying the emitter-nanoparticle separation, and the nanoparticle's size and material. It is shown that HW-HDM and Q-HDM may generate striking spectral features, which do not arise within the classical approach.
|
|
| 8. |
- Marinovic, Tomislav, et al.
(författare)
-
Comparison of CBFM-Enhanced Iterative Methods for MoM-Based Finite Antenna Array Analysis
- 2022
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 70:5, s. 3538-3548
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper we compare different iterative techniques enhanced by the CBFM, that are used to analyze finite arrays of disjoint antenna elements. These are based on the stationary-type methods (Jacobi, Gauss-Seidel, macro-block Jacobi), the nonstationary GMRES and the hybrid alternating GMRES-Jacobi (AGJ) method which combines these two types. In each iteration, the reduced CBFM system is constructed based on the previous iterates, the solution of which is used to update the solution vector in the next iteration with improved accuracy. In this way, the convergence of the classical iterative techniques can be greatly improved. The convergence rates and computational costs of the CBFM-enhanced iterative methods are analyzed by considering several MoM-based problems. The GMRES-based method, which employs the block-Jacobi preconditioner, outperforms the other methods when the MoM matrix is ill-conditioned. For well-conditioned MoM matrices with reduced diagonal dominance due to increased presence of the inter-element coupling effects, the AGJ method or the methods based on the stationary-type iterations may require smaller computational effort to converge to the desired solution accuracy in comparison to the GMRES-based approach.
|
|
| 9. |
- Marinovic, Tomislav, 1991, et al.
(författare)
-
Fast Characterization of Mutually Coupled Array Antennas Using Isolated Antenna Far-Field Data
- 2021
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 69:1, s. 206-218
-
Tidskriftsartikel (refereegranskat)abstract
- A new method is proposed to analyze antenna arrays including mutual coupling, which is based on the concept of multiple scattering and relates to the iterative Jacobi and Gauss-Seidel methods. The method employs sampled far-field data of an isolated element, which can be obtained by any full-wave simulator and consists of far fields for excitation at the antenna feed and for plane waves with different angles of incidence. Mutual interactions between the array elements are modeled by approximating the incident field as a single dual-polarized plane wave taken from the spherical wave expansion of the scattered field from any other element in the array. The accuracy and run-time performances of the method are evaluated mainly by comparing simulations for several array geometries to MoM-based full-wave solutions. The method is primarily intended as a tool for the fast sequential analysis of arrays while varying the array lattice, particularly in case of irregular or sparse lattices and complex elements requiring dense meshes in full-wave simulators. The applications of the method may thus range from the systematic analysis of mutual coupling to optimization and synthesis.
|
|
| 10. |
- Marinovic, Tomislav, 1991, et al.
(författare)
-
On the convergence of the iterative gauss-seidel-based electric field algorithm for the solution of antenna array mutual coupling
- 2021
-
Ingår i: 2020 International Symposium on Antennas and Propagation, ISAP 2020. ; , s. 271-272
-
Konferensbidrag (refereegranskat)abstract
- Recently, a new method for the solution of the antenna array mutual coupling (MC), which is based on the field data of an isolated element and relates to the iterative Gauss-Seidel method, has been proposed. In this paper, we study the convergence of the proposed method by comparing it with the convergence of the classical Gauss-Seidel iteration applied to a method-of-moments (MoM) system. Despite several approximations being used in the field-based method, similar behavior between the two methods has been observed, both in terms of the stability and the rate of the convergence.
|
|
