| 1. |
- 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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| 2. |
- Saad, Paul, 1983, et al.
(författare)
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Doherty Load Modulation Based on Non-Reciprocity
- 2021
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Ingår i: 2021 51st European Microwave Conference, EuMC 2021. ; , s. 938-941
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Konferensbidrag (refereegranskat)abstract
- This paper presents a new type of Doherty power amplifiers (DPA) based on non-reciprocal power combiners. We replace the conventional quarter-wave (λ/4) impedance inverter in a DPA by a non-reciprocal gyrator. As proof of concept, a DPA using a commercial circulator has been implemented. The prototype PA exhibits a peak output power of 49.1 ± 0.1dBm and efficiency between 57-68% at 6 dB output back-off (OBO) across 2.08 -2.14 GHz. Linearized modulated measurements, using 10MHz LTE signal with 7.8 dB PAPR, show an average output power of 13 W, an average drain efficiency of 54 %, and an adjacent channel leakage ratio (ACLR) lower than -55 dBc.
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| 3. |
- Zhou, Han, 1994, et al.
(författare)
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A Generic Theory for Design of Efficient Three-stage Doherty Power Amplifiers
- 2022
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 70:2, s. 1242-1253
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Tidskriftsartikel (refereegranskat)abstract
- An analytical load-pull based design methodology for three-stage Doherty power amplifiers (PAs) is presented and demonstrated. A compact output combiner network, together with the input phase delays, is derived directly from transistor load-pull data and the design requirements. The technique opens up a new design space for three-stage Doherty PAs with reconfigurable high-efficiency power back-off levels. The method is designed to enable a high transistor power utilization by maintaining full voltage and current swings of the main and auxiliary amplifier cells. Therefore, a wide efficiency enhancement range can be achieved also with symmetrical devices. As a proof of concept, a 2.14-GHz 30-W three-stage Doherty PA with identical GaN HEMT active devices is designed, fabricated and characterized. The prototype PA is able to linearly reproduce 20-MHz long-term evolution signals with 8.5- and 11.5-dB peak-to-average power-ratio (PAPR), providing average efficiencies of 56.6% and 46.8% at an average output power level of 36.8 and 33.8 dBm, respectively. Moreover, an average efficiency as high as 54.5% and an average output power of 36.3 dBm have been measured at an adjacent power leakage ratio of -45.7 dBc for a 100-MHz signal with 8.5-dB of PAPR, after applying digital pre-distortion linearization.
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| 4. |
- Argaez Ramirez, Roger, 1991, et al.
(författare)
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Investigation of power amplifier performance under load mismatch conditions
- 2021
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Ingår i: 2021 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications, PAWR 2021. ; , s. 41-43
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Konferensbidrag (refereegranskat)abstract
- The time-varying loading conditions that power amplifiers (PAs) experience in active antenna systems degrade their overall performance. Consequently, the design of linear and highly-efficient PAs under mismatch is more important than ever. In this paper, different common and promising PA architectures, i.e. class-B, balanced, Doherty (DPA) and load-modulated-power-amplifier (LMBA), are analyzed under mismatch. Their sensitivity in terms of linearity, efficiency and output power is compared under a LTE signal excitation. Average drain efficiency (DE), average output power, normalized-mean-square-error (NMSE) as well as maximum output power variations are presented for each architecture as function of the voltage-standing-waveratio (VSWR). Thereby, the most suitable PA architecture to be integrated in active antenna systems may be identified.
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| 5. |
- Bagheri, Alireza, et al.
(författare)
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TX Beamforming EVM Performance of a 65 dBm-EIRP Slant-Polarized Gapwaveguide Phased Array at 28 GHz
- 2023
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Ingår i: 17th European Conference on Antennas and Propagation, EuCAP 2023.
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Konferensbidrag (refereegranskat)abstract
- The transmit error vector magnitude (EVM) performance measurements of a slant-polarized 28 GHz gapwaveguide-based phased array is analyzed in this paper. The performance is studied by using a large range of signals, with varied powers, symbol rates, and quadrature amplitude modulation (QAM) orders. The measurements have been conducted for four different scanning angles. A non-standardized over-the-air (OTA) link between the phased array and the receiver in a laboratory environment is used. The results show that the phased array antenna supports a 31 dB effective isotropic radiated power (EIRP) dynamic range at a maximum 2% EVM when transmitting a 64QAM modulated signal with 250 MS/s symbol rate at all scanning directions.
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| 6. |
- Buisman, Koen, 1978, et al.
(författare)
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Emulation of a Multi-Stage Differential Amplifier Using one Single-Ended Device-Under-Test
- 2021
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Ingår i: 2021 96TH ARFTG MICROWAVE MEASUREMENT CONFERENCE (ARFTG): MEASUREMENT TECHNIQUES FOR ACCELERATING THE DESIGN OF 5G CIRCUITS AND SYSTEMS.
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Konferensbidrag (refereegranskat)abstract
- A method to emulate multi-stage power amplifier (PA) architectures is presented. The technique predicts multi-stage PA performance. The method is based on an iterative procedure using transistor/branch PA active load-pull measurements to include inter-stage interaction. As a benefit, real-world performance of a multi-stage PA can be evaluated early in the design process. Compared to previous published work, the method requires only a single representative device-under-test to embody multi-stage architectures. Thus, a compelling measurement method for PA designers is presented. The method is demonstrated by emulating a two-stage differential amplifier at 2.14 GHz using single-tone signals.
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| 7. |
- Buisman, Koen, 1978, et al.
(författare)
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Mixed-Mode Active Load-Pull Using one Single-Ended Device-Under-Test
- 2021
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Ingår i: 2021 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications, PAWR 2021. ; , s. 20-23
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Konferensbidrag (refereegranskat)abstract
- A method to emulate differential transmitter architectures is presented. The technique, which is based on mixed-mode active load-pull measurements, predicts power amplifier (PA) performance while avoiding the need to manufacture the complete PA. The method is based on an iterative procedure using transistor/branch PA active load-pull measurements together with the S-parameters of the load network. Advantageously, real world performance of the complete differential PA can be evaluated in the design stage. Thereby, many different output combiners and configurations, e.g., biases, transistors, and branch phases, can be fully evaluated without fabrication. Compared to prior art, the method requires only a single representative device-under-test, while providing flexibility in the input signal and the target load network. Thus, a novel powerful measurement tool for PA designers is presented. The technique is demonstrated by performing mixed-mode load-pull and emulating a differential amplifier at 2.14 GHz using continuous wave signals.
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| 8. |
- Perez-Cisneros, Jose-Ramon, 1983, et al.
(författare)
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An Active Load-Pull Technique to Emulate Outphasing Power Amplifiers
- 2021
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Ingår i: 2021 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications, PAWR 2021. ; , s. 24-27
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Konferensbidrag (refereegranskat)abstract
- A general measurement-based design methodology for outphasing transmitter architectures is presented. The emulation technique allows to predict the full real world performance of the outphasing scheme without requiring to fabricate the complete power amplifier (PA). Simply, iterative active load-pull measurements of a single branch PA together with the Sparameters of the output combiner are needed. The method determines the authentic dynamic loading condition of both branch PAs by revealing the internal interactions between the nonlinear active devices. Thereby, the insight into the dynamics of load modulation during the outphasing operation provided by the technique, allows PA designers to optimize circuit performance. The design methodology is demonstrated by emulating an outphasing scheme at 2.14 GHz operated in pure-and mixed-mode.
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| 9. |
- Perez-Cisneros, Jose-Ramon, 1983, et al.
(författare)
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Emulation of Load Modulated Amplifiers Using Tabulated Load-Pull Data from a Single Amplifier
- 2021
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Ingår i: 2020 50th European Microwave Conference, EuMC 2020. ; , s. 676-679
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Konferensbidrag (refereegranskat)abstract
- A method to emulate load modulated power amplifier (PA) architectures is proposed. Based on an iterative procedure, true load modulation trajectories are found using simulated or measured load-pull data from the transistor/branch PA together with the S-parameters of the combiner. Advantageously, real world performance of the complete load modulated PA can be evaluated in the design stage. Thereby, many different combiners and configurations (e.g. biases, transistor size ratios, branch phase differences) can be fully evaluated without having to manufacture anything. Furthermore, the disclosed method utilizes tabulated load pull date, which speeds up evaluation significantly compared to prior art. Hence, a novel powerful tool for PA designers is provided. The technique is demonstrated and verified by emulating a Doherty amplifier and an outphasing scheme at 3.5 GHz using CW signals.
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| 10. |
- Perez-Cisneros, Jose-Ramon, 1983, et al.
(författare)
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Emulation of Non-Reciprocity applied in Load-Modulated Power Amplifier Architectures using Single Amplifier Load-Pull Measurements
- 2021
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Ingår i: 2021 51st European Microwave Conference, EuMC 2021. ; , s. 647-650
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Konferensbidrag (refereegranskat)abstract
- An active load-pull measurement technique is exploited to test the performance of novel high-efficiency power amplifier (PA) concepts based on non-reciprocity. This technique allows new PA architectures, including its load-modulation, to be evaluated before any construction is necessary. Merely active load-pull measurements of a single representative device or PA, in combination with knowledge of the S-parameters of the output combiner, are needed. As a result of the technique, the load modulation on the branch PAs are exposed, thereby allowing PA designers to optimize PA performance. The technique is demonstrated by emulating a load-modulation PA, consisting of two branch PAs with their outputs combined using a non-reciprocal circulator. The resulting PA concept is designed and evaluated at 2.14 GHz.
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