Robust Plane Wave Generator Design in Small Anechoic Chamber Setup Using Parameterized Field Method

Abstract

Plane Wave Generator (PWG) has attracted great research interest in the industry and academia for sub-6 GHz massive MIMO base station (BS) measurement, thanks to its low-cost and smaller system setup. One major concern in the small setup is its high reflectivity level inside the anechoic chamber, which might distort the quiet zone performance significantly. Meanwhile, it is critical that the quiet zone performance is insusceptible to system inaccuracies. However, these two aspects are largely overlooked in the plane wave synthesis (PWS) study in the literature. In this paper, a new PWS strategy is proposed based on parametrized field distribution over an enlarged sampling area. The proposed method offers robust design and low reflectivity level. The effectiveness and robustness of the proposed PWS strategy is demonstrated in a numerical simulation. INDEX TERMS Excitation coefficient optimization, over-the-air testing, plane wave generators, small anechoic chamber.

Effective Sparse Recovery Framework for Ultrawideband Robust Plane Wave Generator

“…In the proposed strategies, the over-fitting problem [8] could be significantly relieved with the constrained regression strategy (also with the amplitude-only excitation constraint). Note that Lmax û should be restricted to avoid coupling.…”

“…α max and α min are the maximum and minimum amplitude in the QZ, respectively, while ψ max and ψ min are the maximum and minimum phases in the QZ, respectively. ε is a scaling factor set to 0.1 in this work and can be flexibly adjusted according to the performance requirements [8].…”

“…The basic principle of PWG is to coherently synthesize the plane wave field in the quiet zone (QZ) via properly allocating excitations for the contained antennas. Various methodologies, e.g., in [6][7][8][9][10][11][12], have been developed to determine the optimal locations and excitations of PWG antennas for a highquality and cost-effective plane wave synthesis. For example, a systematic guideline on the PWG geometrical design and the stability of the solution are studied in [9].…”

“…Most of them, however, are limited to narrowband applications and require rigorous amplitude and phase feeding control, except for the tapering methods [11]. However, it is typically applied for the PWG with a large aperture and is not ideal for the small anechoic chambers [8]. In addition, although several commercial PWG systems have been reported in recent years [12], the design details were not given.…”

“…Compressed sensing has been widely utilized in various engineering fields of research [13][14][15] and is employed to determine a sparse PWG array in this letter. The sparse recovery generally results in non-uniform arrays, and such arrangements are demonstrated to support ultra-wideband PWG performance [8] and reduce array truncation effects [17]. Furthermore, this strategy effectively reduces the number of required antenna elements, reducing the cost of the PWG system.…”