Load-Pull Effect on Radiation Characteristics of Active Antennas

Romier, M.; Barka, André; Aubert, Hervé; Martinaud, Jean-Paul; Soiron, Michel

doi:10.1109/lawp.2008.2005652

Cited by 23 publications

(13 citation statements)

References 8 publications

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“…where A 1i (n) and A 2i (n) are the two incident wave phasors, and B 21 (n) is the corresponding scattered wave. PHD models have been used to predict radiation patterns of active antenna arrays [4], [10]. However, since they are quasi-static and, as such, do not consider the history of the input signals, they are not suitable for wideband signals.…”

Section: B Reduced Dual-input Pa Modelsmentioning

confidence: 99%

“…T , a T . The linear least-squares method can be used for all dual-input models given in this work, i.e., the full Volterra series-based model in (3) and (19), the model with memory polynomial structure in (4) and the memoryless model in (5). Using the measured signals, the model output is written in matrix form as…”

Section: B Least-squares Identification Of Model Coefficientsmentioning

confidence: 99%

“…(PAs) and antennas [4]. However, such designs are vulnerable to crosstalk due to mutual coupling between the antennas, and antenna mismatches.…”

mentioning

confidence: 99%

“…In [4] and [10] a hardware oriented approach is used to predict radiation patterns of active antenna arrays with direct connections between PAs and antennas. In both papers, dualinput PA models based on polyharmonic distortion (PHD) models (nonlinear scattering functions) [11], and antenna Sparameters are used to investigate the effects of mutual antenna coupling and mismatches on the behavior of PAs and on the overall performance of a TX antenna array.…”

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confidence: 99%

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Prediction of Nonlinear Distortion in Wideband Active Antenna Arrays

Hausmair

Gustafsson

Sánchez-Pérez

et al. 2017

IEEE Trans. Microwave Theory Techn.

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In this paper we propose a technique for comprehensive analysis of nonlinear and dynamic characteristics of multiantenna transmitters (TXs). The analysis technique is enabled by the development of a Volterra series-based dual-input model for power amplifiers (PAs), which is capable of taking into account the joint effects of PA nonlinearity, antenna crosstalk and mismatch for wideband modulated signals. By combining multiple instances of the PA model with linear dynamic antenna simulations we develop the analysis technique. The proposed method allows the prediction of the output signal of every antenna in an arbitrarily sized TX array, as well as the total far-field radiated wave of the TX for any input signal with low computational effort. A 2.12 GHz four-element TX demonstrator based on GaAs PAs is implemented to verify simulation results with measurements. The proposed technique is a powerful tool to study hardware characteristics, as for example the effects of antenna design and element spacing. It can be used in cases where experiments are not feasible, and thus aid the development of next generation wireless systems. Index Terms-Active antenna array, antenna crosstalk, mismatch, MIMO transmitter, power amplifier modeling I. INTRODUCTION Wireless communication systems face a steadily growing demand for higher data rates. However, the radio spectrum is a limited resource. Multiple-input multiple-output (MIMO) systems can be utilized to increase spectral efficiency [1]. For this reason, modern wireless telecommunication standards, such as LTE and Wi-Fi, include the use of multiple antennas. Largescale antenna systems, which comprise hundreds of antennas, have become a hot topic in the research community [2]. The use of several transmit paths in a transmitter (TX) increases system complexity and cost [3]. Therefore, integrated solutions, as have been used in, e.g., radar applications for many years, are preferred. Such integrated designs avoid costly components like bulky isolators between power amplifiers This research has been carried out in GigaHertz Centre in a joint project financed by the

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Section: B Reduced Dual-input Pa Modelsmentioning

confidence: 99%

Section: B Least-squares Identification Of Model Coefficientsmentioning

confidence: 99%

“…(PAs) and antennas [4]. However, such designs are vulnerable to crosstalk due to mutual coupling between the antennas, and antenna mismatches.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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Prediction of Nonlinear Distortion in Wideband Active Antenna Arrays

Hausmair

Gustafsson

Sánchez-Pérez

et al. 2017

IEEE Trans. Microwave Theory Techn.

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show abstract

“…Therefore, integrated system designs are used where expensive and bulky components like isolators between PAs and antennas are avoided to reduce system complexity and cost. However, such systems are vulnerable to antenna crosstalk due to mutual coupling and antenna mismatches [3]. As a consequence, integrated multi-antenna transmitters typically suffer from nonlinear distortion due to the mixing of the antenna crosstalk and mismatch with the PA output, in addition to the nonlinear distortion caused by the behavior of the PAs [4], [5].…”

Section: Introductionmentioning

confidence: 99%

Digital Predistortion for Multi-Antenna Transmitters Affected by Antenna Crosstalk

Hausmair

Landin

Gustavsson

et al. 2018

IEEE Trans. Microwave Theory Techn.

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In this paper, a digital predistortion (DPD) technique for wideband multi-antenna transmitters is proposed. The proposed DPD compensates for the combined effects of power amplifier (PA) nonlinearity, antenna crosstalk and impedance mismatch. The proposed technique consists of a linear crosstalk and mismatch model block shared by all transmit paths, and a dual-input DPD block in every transmit path. By avoiding the use of multi-input DPD blocks in every transmit path, the complexity of the proposed technique is kept low and scales more favorably with the number of antennas than competing techniques. It is shown that all blocks can be identified from measurements of the PA output signals using least-squares estimation. Measurement results of a four-path transmitter are presented and used to evaluate the proposed DPD technique against existing techniques. The results show that the performance of the proposed DPD technique is similar to those of existing techniques, while the complexity is lower.

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Over-the-Air Suppression of Third-Order Intermodulation in a Two-Beam Steered Amplifier-Antenna Array

Kutinlahti,

Lehtovuori,

Viikari

2023

IEEE Access

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The effect of load-pull on 3rd order intermodulation (IM3) radiation characteristics of a transmitting active phased array is studied and a general model for predicting the spatial distribution of fundamental tones and intermodulation products is introduced. The used data is obtained from a load pull measured amplifier prototype and a simulated linear antenna array, which are used in co-simulation of the system behavior. The system is optimized for maximum main tone beam powers with a two-tone excitation while satisfying a signal-to-IM3 ratio (SI3R) of 40 dB. In this paper, we demonstrate the case, where two separate beams are scanned independently from each other. The used load-pull system model achieves on average an improvement of 10.4 dB for SI3R, when compared to traditional small-signal modelling, while decreasing the main beam power densities by only 0.3 dB when compared to traditional small-signal modelling. Optimizing for SI3R degrades beam pattern by increasing beamwidths and decreasing sidelobe levels (SLL).INDEX TERMS Active phased arrays, amplifier, beam-steering, intermodulation, load pull, third-order intermodulation product (IM3)

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Load-Pull Effect on Radiation Characteristics of Active Antennas

Cited by 23 publications

References 8 publications

Prediction of Nonlinear Distortion in Wideband Active Antenna Arrays

Prediction of Nonlinear Distortion in Wideband Active Antenna Arrays

Digital Predistortion for Multi-Antenna Transmitters Affected by Antenna Crosstalk

Over-the-Air Suppression of Third-Order Intermodulation in a Two-Beam Steered Amplifier-Antenna Array

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