Single-cut phaseless measurements enable the testing of antenna devices with no reference channel by measuring and transforming to far-field individual pattern cuts. This typically requires performing two single-cut measurements at different distances which may be infeasible or too time consuming in some antenna facilities. As an alternative, this communication proposes the use of a two-probe system connected to the same coherent receiver. The relative phase between probes is exploited to retrieve the absolute phase using a state-of-the-art linearized phase retrieval approach. Simulations and measurements are performed to validate the technique which includes an innovative probe-to-probe calibration method.

Emerging 5G and Beyond wireless systems are putting the focus on millimeter-wave (mmW) and sub-THz antenna systems with multiple beams and a large number of elements yielding electrically large and complex radiant systems such as Reflective Intelligent Surfaces (RIS) or Massive MIMO panels. Characterization of those antennas may be unfeasible by means of conventional near-field techniques due to the required sampling schemes and high acquisition times. This work proposes a fast Planar Near-Field (PNF) technique based on sparse acquisitions. Singular Value Decomposition (SVD) techniques are employed to reduce the number of unknowns of the inverse problem and to design a non redundant measurement grid. By restricting the near-field to far-field transformation problem to a reduced domain of the antenna radiation pattern, a time-efficient characterization of the mentioned antennas is achieved. The proposed technique has been validated through numerical an measurement examples demonstrating its potential for fast and robust PNF measurements of narrow beam antenna patterns with large tilt angles.

In this paper, a millimeter-wave (mmWave) 5G communication prototype composed of a phased array antenna and a transceiver is proposed. The prototype involves a custom-manufactured planar active phased array antenna featuring linear polarization, which incorporates a beamforming integrated circuit (BFIC) comprising an 8×8-element planar array. The 27 GHz transceiver is a prototype fabricated with off-the-shelf components and designed to downconvert/upconvert signals from 3.5 GHz to 27 GHz. Additionally, a 3GPP-inspired gNodeB based on the FR2 5G signal, which introduces a phase tracking reference signal (PT-RS) and implements a phase noise cancellation (PNC) algorithm in the user equipment (UE) node, was emulated. A measurement campaign in an indoor scenario, including validation using commercial equipment and a comparison with a passive antenna for the Q-PSK and 16-QAM modulation schemes has been carried out. The obtained results support that the integration of a phased array antenna is a promising technology for the future of wireless communications.

This paper presents the calibration process involved in a planar active phased array antenna operating in the K-band (17.7–20.2 GHz). The array consists of eight columns, each containing a 1 × 8 subarray of patch antennas. To enhance the antenna bandwidth, a double-stacked patch structure is employed. We analyze the challenges encountered when measuring active antennas. Additionally, we discuss the solutions and calibration techniques used to improve the array performance. Finally, we present the results of the optimal calibration approach, comparing simulated and measured data, both with and without calibration, to evaluate the improvements achieved.

This paper comprehensively examines the non-idealities inherent in commercially available beamformers and explores their implications in the calibration procedures for phased array antennas. The non-ideal nature of the beamformer is meticulously modeled and assessed through extensive S-Parameter measurements to discern its impact on analyzed excitation retrieval methods. The Rotating-element Electric-field Vector (REV) and Control Circuit Encoding (CCE) methods are simulated using a synthetic array with spherical wave expansion driven by output coefficients measured from the beamformer. Simulations are executed to compare the REV method with a Selective-REV variant, designed to enhance coefficient prediction accuracy by leveraging a priori knowledge of phase-shifter amplitude deviations. Additionally, amplitude, phase, and complex CCE encodings are employed to determine the encoding technique that best accommodates beamformer non-idealities. Finally, anechoic chamber measurements assess the pattern prediction capabilities of the analyzed methods, and an iterative calibration scheme is proposed to compensate for the studied beamformer errors due to its behavior.