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Three‐dimensional (3D)‐MIMO beamforming realised by adaptive quantum particle swarm optimisation (AQPSO) algorithm for the 36‐element cylindrical conformal phased array is proposed in this study. The cylindrical conformal phased array consists of 36 circularly polarised microstrip antenna elements with ultra‐wideband and high gain characteristics. The conformal array is divided into 12 subarrays using reconfigurable technology, and each subarray produces six beams to cover the corresponding spatial area. The 3D‐MIMO beam is formed by AQPSO, and the active element pattern data of array elements is introduced to AQPSO to improve the accuracy of the algorithm. The simulated and measured results show that the cylindrical conformal phased array can achieve 3D‐MIMO beam coverage from 0° to 360° in the azimuth plane and from 67.5° to 112.5° in the elevation plane. It can be applied for satellite communication and fifth‐generation base station communication.

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A broadband and high gain circularly polarized stacked antenna with small size was designed. The antenna includes a double‐Y type slot radiator and two slot‐loaded patches with chamfering. Right hand circular polarization performance is achieved by adjusting the length of the two branch of Y type slot. In order to expand the antenna impedance bandwidth and axial ratio (AR) bandwidth, multilayer structure was used. Two patches with chamfering were chosen for radiating element. With the form of orthogonal, rectangular slot cut on the center of the two patches, small size of antenna can be achieved. The measurements show that, the proposed antenna's −10 dB impedance bandwidth is 32.7% (from 4.1 to 5.7 GHz), the 3 dB (AR) bandwidth is 20.7% (from 4.4 to 5.4 GHz) and the gain of the antenna is about 9 dB, which agree well with the simulations. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:292–298, 2017