| 1. |
- Fager, Christian, 1974, et al.
(författare)
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IC Design Aspects for 5G mm-Wave Systems
- 2020
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Ingår i: 2020 50TH EUROPEAN MICROWAVE CONFERENCE (EUMC). - 2325-0305. - 9782874870590 ; , s. 870-871
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Iupikov, Oleg, 1983, et al.
(författare)
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A Cavity-Backed Patch Antenna with Distributed Multi-Port Feeding, Enabling Efficient Integration with Doherty Power Amplifier and Band-Pass Filter
- 2021
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 69:8, s. 4412-4422
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Tidskriftsartikel (refereegranskat)abstract
- A joint design approach for co-integrated antenna and power amplifier (PA), employing a high-efficiency Doherty PA (DPA) architecture and including a band-pass RF filter, is proposed. This design is realized through the optimally distributed and balanced multi-port feeding of the cavity-backed patch antenna element that provides the desired (unique) loading conditions for the main and auxiliary PA branches and tailored power combining. A novelty and advantage of this feeding solution is that each pair of feeding points form a virtual common feeding centre of the radiating element; as a result, the radiation pattern remains power invariant when the port excitations change. A joint optimization of the integrated antenna-DPA transmitter is carried out to enhance the overall performance and maximize the bandwidth. This optimization is demonstrated through an example design for the sub-6 GHz telecommunication applications that target high power-efficiency (>50%) at the 6dB backed-off power levels and require RF-filtering in a compact integrated design. The latter challenge leads to a non-conventional implementation, which generally does not require the filter to be inserted between the antenna and the final output stage of the PA, and can be embedded in the topology with complex-valued source/load impedance values. Results of numerical studies are supported by measurements obtained with the antenna-DPA-filter prototype system.
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| 3. |
- Iupikov, Oleg, 1983, et al.
(författare)
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A Dual-Fed PIFA Antenna Element With Nonsymmetric Impedance Matrix for High-Efficiency Doherty Transmitters: Integrated Design and OTA-Characterization
- 2020
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 68:1, s. 21-32
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Tidskriftsartikel (refereegranskat)abstract
- A single planar inverted F-antenna is proposed employing two input ports to optimally power-combine the output signals of two nonlinear power amplifiers inside the metal-only low-loss antenna structure. High power-added efficiency (PAE) at back-off power levels is reached through a Doherty combiner architecture, where the optimal power combination is seen to generally require the synthesis of a nonsymmetric antenna input impedance matrix. The dual-fed antenna is compact and exhibits close to single-mode radiation properties; it has a relatively stable gain pattern despite the nonequal Doherty power amplifier (PA) output powers. An integrated active prototype has been designed, fabricated, and characterized over-the-air in both an anechoic and a reverberation chamber. Good agreement is observed and an uncertainty analysis is performed. The Doherty transmitter features a max-PAE of 58 at 2.14 GHz and a 6 dB back-off PAE of 52; a minimum system power gain of 9.5 dB (max 12 dB); and a maximum system output power of 43.5 dBm.
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| 4. |
- Aljarosha, Alhassan, 1982, et al.
(författare)
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A Wideband Contactless and Bondwire-Free MMIC to Waveguide Transition
- 2017
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Ingår i: IEEE Microwave and Wireless Components Letters. - 1558-1764 .- 1531-1309. ; 27:5, s. 437-439
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Tidskriftsartikel (refereegranskat)abstract
- A contactless transition from a high-permittivity microstrip line (e_r=9.9) to an air-filled waveguide (WG) has been impedance-matched over a large simulated relative bandwidth of 38% (W-band, 75-110 GHz). The transition couples the EM fields directly from the MMIC's microstrip line via an SIW and an off-chip stub section to a ridge WG section. The novel structure is low loss and suits pick-and-place assembly techniques of mm-Wave MMICs inside metal WGs. The design process is detailed and manufacturing tolerances of the Alumina prototype PCB are discussed. The measured back-to-back structure retains an appreciable insertion loss smaller than 0.8 dB for a single transition and a fractional bandwidth of 28% (72-95~GHz) over which the return loss is greater than 10 dB.
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| 5. |
- Aljarosha, Alhassan, 1982, et al.
(författare)
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Mm-Wave contactless connection for MMIC integration in gap waveguides
- 2016
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Ingår i: 2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016, Fajardo, Puerto Rico, 26 June - 1 July 2016. - 1522-3965. ; , s. 253-254
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Konferensbidrag (refereegranskat)abstract
- A contactless, broadband and low-loss microstrip-to-groove gap waveguide transition operating at W-band is presented. The principle of operation is based on transforming EM fields from the SIW to the ridge gap waveguide mode via electromagnetic coupling. This is advantageous, since the proposed solution avoids the use of metal contact between the SIW and one of the waveguide parts. Furthermore, metamaterial-based gap waveguide technology provides a resonance-free packaging solution.
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| 6. |
- Aljarosha, Alhassan, 1982, et al.
(författare)
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Performance Analysis of an Integrated Multi-Channel Power Amplifier Incorporating an IC-to-Waveguide Transition
- 2021
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Ingår i: 2021 15TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP). - 2164-3342.
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Konferensbidrag (refereegranskat)abstract
- This paper studies the power combiner efficiency of multiple Power Amplifier (PA) output signals that are combined within a low-loss contactless transition, intrinsically having low isolation characteristics. Since the PA performance is sensitive to load impedance variations, poor isolation may affect each PA performance, thereby reducing the overall power combiner efficiency. Load impedance variations can e.g. be due to process, supply-voltage and temperature variations. A four-way spatial power combiner (SPC) design is compared to an on-chip Wilkinson Power Combiner (WPC) implemented in 0.13 mu m SiGe BiCMOS technology incorporating a 50 Omega impedance matching network. The WPC occupies 84% more area than the non-isolating SPC. Moreover, the non-isolating SPC has an average efficiency 14% larger than the WPC. For physically realistic variations, simulated results show a sigma-variation of 2.81 mW in P-out and 0.87 % in PAE for the non-isolating SPC, and 2.34 mW in P-out and 0.45 % in PAE for the WPC (@1 dB compression).
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| 7. |
- Aljarosha, Alhassan, 1982, et al.
(författare)
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Performance comparison of silicon substrates for IC-waveguide integration based on a contactless transition at mm-wave frequencies
- 2019
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Ingår i: 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, APSURSI 2019 - Proceedings. ; July 2019, s. 1081-1082
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Konferensbidrag (refereegranskat)abstract
- This paper presents a comparison between different silicon (Si) substrates used in Si-based IC technologies at E-Band (71-86 GHz). A unique low-loss and compact contactless transition from a silicon IC (p-doped substrate) to a metal waveguide is used. The proposed transition incorporates a spatial power combiner to enable direct electromagnetic coupling from an array of patches on the IC to a metal waveguide. This design enables a high-power transition from an IC to a waveguide and/or antenna at millimeter-wave (mm-wave) frequencies, where a galvanic contact between the two parts is avoided.
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| 8. |
- Aljarosha, Alhassan, 1982, et al.
(författare)
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Silicon-Based IC-Waveguide Integration for Compact and High-Efficiency mm-Wave Spatial Power Combiners
- 2021
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Ingår i: IEEE Transactions on Components, Packaging and Manufacturing Technology. - 2156-3985 .- 2156-3950. ; 11:7, s. 1115-1121
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Tidskriftsartikel (refereegranskat)abstract
- A novel and compact millimeter-wave spatial power combiner is developed integrating a Silicon-based integrated circuit (IC) in a metal waveguide. As an initial step towards integrating a silicon-based active IC in a waveguide, a passive back-to-back transition incorporating a 4-way spatial power splitter and combiner is realized at E-band (71–86 GHz). In contrast to existing solutions, the proposed design considers power splitting and combining using a low-loss wireless transition between the IC and the waveguide. The proposed back-to-back structure comprises an IC implemented using Institute for High Performance Microelectronics (IHP’s) 0.13μm SiGe BiCMOS technology integrated into the H-plane of a waveguide. The IC is post-processed and assembled in the waveguide prototype. The measured prototype shows a return loss better than 13 dB, an average insertion loss of 1.7 dB for a single transition, and a fractional bandwidth of 26.4 % (69–90 GHz).
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| 9. |
- Aljarosha, Alhassan, 1982, et al.
(författare)
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Toward Wide-Band Low-Loss Gap-Waveguide-Integrated Grid Amplifiers
- 2017
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Ingår i: 2017 International Symposium on Antennas and Propagation (ISAP). - 9781538604656
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Konferensbidrag (refereegranskat)abstract
- A passive W-band 19-channel spatial power splitter/combiner is presented, for the applications in grid amplifiers design. The design employs a linear array of chip-to-air-filled waveguide contactless connections, and are directly integrated within a single-layer. The meta-material-based gap waveguide is used; it enables a low-loss low-profile solution. The quasi optical beamformer gives rise to a parallel-plate planar waveguide field which excites an array of contactless chip-to-waveguide transitions via step-tapered ridge gap waveguides. The other beamformer restores the field distribution (after amplification) and excites a wave going towards the waveguide output. Furthermore, the gap waveguide technology isolates the amplifiers from one another and provides a packaging solution in a single unit. The simulated return loss of the back-to-back structure is larger than 12 dB, while the insertion loss is smaller than 1.2 dB over the entire W-band (75-110 GHz).
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| 10. |
- Amani, Navid, 1985, et al.
(författare)
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Array Configuration Effect on the Spatial Correlation of MU-MIMO Channels in NLoS Environments
- 2020
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Ingår i: 14th European Conference on Antennas and Propagation, EuCAP 2020. ; 2020:March
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Konferensbidrag (refereegranskat)abstract
- In this paper, three different base-station antenna (BSA) configurations are compared in terms of inter-user spatial correlation in a two dimensional (2D) non-line-of-sight (NLoS) environment. The three configurations are: (i) a regular uniform linear array (ULA); (ii) a periodic sparse array; and (iii) an aperiodic sparse array. Electromagnetic modeling of the NLoS channel is proposed where scatterers are considered as resonant dipoles confined in clusters of scatterers (CoSs). While the probability of facing highly correlated user-equipments (UEs) in a multi-user multiple-input multiple-output (MU-MIMO) system is decreasing as the richness of mutipath increases, the sparsity (increased inter-element spacing) is seen to be capable of reducing this probability as well. This is due to the larger spatial variations experienced by the sparse array. Moreover, the results show that further improvement can be achieved by deploying an aperiodic distribution of antenna elements into the sparse antenna aperture.
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