Power, Linearity, and Efficiency Prediction for MIMO Arrays With Antenna Coupling

Barradas, Filipe M.; Tome, Pedro M.; Gomes, J. M.; Cunha, Telmo R.; Cabral, Pedro M.; Pedro, José C.

doi:10.1109/tmtt.2017.2766067

Cited by 51 publications

(24 citation statements)

References 14 publications

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“…Since the array elements are electromagnetically coupled, the waves fed to the antennas are also coupled back to the output ports of the PAs. This effect creates an apparent variable load at the output of each PA, depending on the operation of the transmitter [22]. Then the effective reflection coefficient (Γ k ) for the k'th element is given by:…”

Section: Crosstalk Mitigation State-of-the-art Solutionsmentioning

confidence: 99%

Linearization Trade-Offs in a 5G mmWave Active Phased Array OTA Setup

et al. 2020

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The new generation of 5G mobile communication systems is using millimeter wave (mmWave) active phased arrays (APA) which have up to hundreds of individual analog transmitter and receiver chains and antennas. For these highly integrated systems linearization of each analog path is very challenging. Therefore a single input single output (SISO) system in combination with over the air (OTA) measurement is considered as an efficient approach for linearization. However, the knowledge about the dependency of the total SISO nonlinearity on the contributions from different blocks in the antenna array, as well as the linearization trade-offs is still missing. In this paper, an overview of the possible linearization trade-offs in an OTA setup with a mmWave APA is provided. The linearization technique is applied to a 4x4 active phased array containing up-conversion of a sub 6 GHz LTE10 signal to an RF frequency of 28 GHz. Through measurements, the effects on adjacent channel power ratio (ACPR) and error vector magnitude (EVM) have been investigated for the following scenarios: i. impact from the up-converter, ii. impact of the steering angle due to antenna crosstalk and iii. a linearity comparison between a linearized and a backed-off system. INDEX TERMS active phased array (APA), single input single output (SISO), over the air (OTA), power amplifier (PA), millimeter wave (mmWave), digital pre-distortion (DPD).

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Section: Crosstalk Mitigation State-of-the-art Solutionsmentioning

confidence: 99%

Linearization Trade-Offs in a 5G mmWave Active Phased Array OTA Setup

et al. 2020

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“…The structure employs the RO4350 laminate with thickness 0.254 mm and relative dielectric constant ε r = 3.66. As mentioned above, the output power, efficiency, and non-linear distortion are highly dependent on the PA load impedances [15]. These loads can be represented by active reflection coefficients at the combiner input ports:…”

Section: Design Of the Power Combining Module Including The Effecmentioning

confidence: 99%

“…These active input impedances are the load impedances presented to interconnected PAs. The PA output power, efficiency, and non-linear distortion are highly dependent on the load impedance [15]. Consequently, the combined output power is affected by unequal PA signals; any deviation from the optimum PA load impedance leads to an output power and efficiency reduction [16].…”

Section: Introductionmentioning

confidence: 99%

A Wideband and Low-Loss Spatial Power Combining Module for mm-Wave High-Power Amplifiers

et al. 2020

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We present a low-loss power combiner, providing a highly integrated interface from an array of mm-wave power amplifiers (PAs) to a single standard rectangular waveguide (WG). The PAs are connected to an array of parallel and strongly coupled microstrip lines that excite a substrate integrated waveguide (SIW) based cavity. The spatially distributed modes then couple from the cavity to the rectangular WG mode through an etched aperture and two stepped ridges embedded in the WG flange. A new co-design procedure for the PA-integrated power combining module is presented that targets optimal system-level performance: output power, efficiency, linearity. A commercial SiGe quad-channel configurable transmitter and a standard gain horn antenna were interfaced to both ends of this module to experimentally demonstrate the proposed power combining concept. Since the combiner input ports are non-isolated, we have investigated the effects of mutual coupling on the transmitter performance by using a realistic PA model. This study has shown acceptable relative phase and amplitude differences between the PAs, i.e. within ±15 • and ±1 dB. The increase of generated output power with respect to a single PA at the 1-dB compression point remains virtually constant (5.5 dB) over a 42% bandwidth. The performed statistical active load variation indicates that the interaction between the PAs through the combiner has negligible effect on the overall linearity. Furthermore, the antenna pattern measured with this combiner shows negligible deformation due to non-identical PAs. This represents experimental prove-of-concept of the proposed spatial power combining module, which can be suitable for applications in MIMO array transmitters with potentially coupled array channels. INDEX TERMS Antenna feed, array amplifiers, integration, MMIC, mode converter, spatial power combining.

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“…For these situations, combining PA behavioral models with antenna characteristics is the key to a fast and accurate evaluation of transmitters [14]. A variety of PA behavioral models suitable for MIMO and phased array applications has been addressed in the literature [14]- [22]. However, only a limited number of studies have incorporated PA models into active antenna array simulations for evaluating transmitter performance [14], [18]- [22].…”

Section: Introductionmentioning

confidence: 99%

Hybrid Beamforming Transmitter Modeling for Millimeter-Wave MIMO Applications

Taghikhani¹

2020

Preprint

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<div>Hybrid digital and analog beamforming is an</div><div>emerging technique for high-data-rate communication at</div><div>millimeter-wave (mm-wave) frequencies. Experimental evaluation</div><div>of such techniques is challenging, time-consuming, and costly.</div><div>This article presents a hardware-oriented modeling method for</div><div>predicting the performance of an mm-wave hybrid beamforming</div><div>transmitter. The proposed method considers the effect of active</div><div>circuit nonlinearity as well as the coupling and mismatch in the</div><div>antenna array. It also provides a comprehensive prediction of</div><div>radiation patterns and far-field signal distortions. Furthermore,</div><div>it predicts the antenna input active impedance, considering</div><div>the effect of active circuit load-dependent characteristics. The</div><div>method is experimentally verified by a 29-GHz beamforming</div><div>subarray module comprising an analog beamforming integrated</div><div>circuit (IC) and a 2 × 2 subarray microstrip patch antenna.</div><div>The measurement results present good agreement with the</div><div>predicted ones for a wide range of beam-steering angles. As a</div><div>use case of the model, far-field nonlinear distortions for different</div><div>antenna array configurations are studied. The demonstration</div><div>shows that the variation of nonlinear distortion versus steering</div><div>angle depends significantly on the array configuration and beam</div><div>direction. Moreover, the results illustrate the importance of</div><div>considering the joint operation of beamforming ICs, antenna</div><div>array, and linearization in the design of mm-wave beamforming</div><div>transmitters.</div>

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Power, Linearity, and Efficiency Prediction for MIMO Arrays With Antenna Coupling

Cited by 51 publications

References 14 publications

Linearization Trade-Offs in a 5G mmWave Active Phased Array OTA Setup

Linearization Trade-Offs in a 5G mmWave Active Phased Array OTA Setup

A Wideband and Low-Loss Spatial Power Combining Module for mm-Wave High-Power Amplifiers

Hybrid Beamforming Transmitter Modeling for Millimeter-Wave MIMO Applications

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