Per-Antenna Power Distribution of a Zero-Forcing Beamformed ULA in pure LOS MU-MIMO
Journal article, 2018

An analytical model is presented to determine the per-antenna power distribution of a beamformed M-element uniform linear array (ULA) as a base station antenna (BSA). The analysis assumes a single sector cell serving two user equipments (UEs) in a downlink multiuser multiple-input multiple-output (MU-MIMO) system employing zeroforcing (ZF) transmission. Determinative design parameters of the BSA configuration are identified. Afterwards, their effects on the power spread across the array are investigated when the positions of the users are random and they are uniformly distributed over the cell. It is shown that the power distribution across the ULA antenna aperture is a periodic function whose characteristics mainly depend on the angular separation of two UEs and the number of BSA elements. A significant variation between ULA input powers is seen to occur if the number of elements in the ULA is smaller than one period of this power distribution function. In order to mitigate the dynamic range of the power variation across the array, an upper bound for the inter-element spacing, depending on the field-of-view (FoV) of the BSA, is defined. It is shown that, in a 20-element ULA, increasing the inter-element spacing from 0.5-wavelength to 1.4-wavelength reduces the power variation from 19 dB to 10 dB for differentiating two close-by UEs with 1 degree angular separation.



massive MIMO

base station antenna


uniform linear array


Navid Amani

Chalmers, Electrical Engineering, Communication and Antenna Systems, Antennas

Andres Alayon Glazunov

University of Twente

Chalmers, Electrical Engineering, Communication and Antenna Systems, Antennas

Marianna Ivashina

Chalmers, Electrical Engineering, Communication and Antenna Systems, Antennas

Rob Maaskant

Chalmers, Electrical Engineering, Communication and Antenna Systems, Communication Systems

Eindhoven University of Technology

IEEE Communications Letters

1089-7798 (ISSN)

Vol. 22 12 2515-2518

Silicon-based Ka-band massive MIMO antenna systems for new telecommunication services (SILIKA)

European Commission (Horizon 2020), 2016-09-01 -- 2020-08-31.

Areas of Advance

Information and Communication Technology

Subject Categories


Signal Processing

Other Electrical Engineering, Electronic Engineering, Information Engineering

Driving Forces

Innovation and entrepreneurship



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