3D wave-field synthesis for testing of radio devices

Abstract

For the sake of new radio devices to conform to respective standards, implementing functionality such as cognitive radio, Long Term Evolution beyond 2x2, or Global Navigation Satellite Systems, a demand for extensive testing arises. A promising solution is the validation inside an Over-the-Air testbed that creates a virtual electromagnetic environment using wave-field synthesis. This paper analyzes the polarimetric accuracy of a wave field generated by a hemispheric (3D) antenna arrangement. As most radio devices have a flat shape (e. g. smart phones, tablets, compact cognitive radio antennas) or a metallic backplane along a defined surface, the complexity of the optimization problem can be reduced. Analyzing the wave-field synthesis accuracy, it has to be kept in mind that for most radio devices the signal-to-noise ratio is limited in a range between 0-30 dB, which indirectly defines the upper limits of the required wave-field synthesis accuracy

On Radiated Performance Evaluation of Massive MIMO Devices in Multiprobe Anechoic Chamber OTA Setups

“…The objective of the PWS is to synthesize plane waves with arbitrary impinging angles within the test zone, by allocating appropriate complex weights to the active OTA antennas. Complex weights can be calculated with different techniques, e.g., the least square technique in [13], [25] or the spherical wave expansion in [26], [27]. The minimum required number of OTA antennas to synthesize an arbitrarily polarized field with an arbitrary angle can be expressed, according to the cut-off properties of the spherical wave modes [27], as…”

Accuracy of an OTA system emulating a realistic 3D environment for GNSS and multi-satellite receiver testing

“…For the sake of an homogeneous quality of the wave field across all azimuth and elevation angles to be emulated, a Lebedev grid with 29 points is used (cf. [11], [12] for further details on the emulation antenna distribution). The left plot shows the use of 29 duallinear polarized emulation antennas, where the horizontal and vertical ports can be fed independently.…”

“…This section briefly reviews the wave field synthesis (WFS) fundamentals, presenting the full-polarimetric extension of the previous studies in [11] and [13]. Let K denote the number of transmitting satellites.…”

“…We now address the problem of finding the vector function s. To do so, we define N points uniformly distributed within the sweet spot. The number N is chosen to meet the spatial sampling theorem [11]. Let the position vector o n denote the n-th point.…”

Impact of amplitude weights on power focusing for near-field-focused planar arrays

“…In the past decades, much work on the synthesis, design, and optimization of NFF arrays is reported in the contributions, unlike the field synthesis using multiple antennas. [20][21][22][23] The basic design criteria for NFF planar square arrays is summarized in 19 with the uniform current amplitude. The NF pattern of an antenna array is synthesized by an efficient approach for RFID applications in.…”