Active antenna

About: Active antenna is a research topic. Over the lifetime, 2246 publications have been published within this topic receiving 26493 citations.

Active antenna system

Abstract: The embodiment of the utility model discloses an active antenna system An antenna array of the system comprises antenna sub-arrays and feed sub-networks which are identical in number An antenna interface of a transmission unit of each feed sub-network is connected with positive and negative 45-degree polarized ports of an antenna oscillator of each antenna sub-array One input end of each transmission unit is connected with one receiving end of one combiner, and the other input end of each transmission unit is connected with one receiving end of another combiner One output end of each transmission unit is connected with one sending end of one de-multiplexer, and the other output end of each transmission unit is connected with one sending end of another de-multiplexer The sending end of the combiner is connected with the input end of a radio frequency remote unit The receiving end of the de-multiplexer is connected with the output end of the radio frequency remote unit With adoption of the active antenna system, uplink signal-to-noise ratio gain of a base station can be enhanced, emission power of a 4G mobile phone can be reduced and endurance capacity of the mobile phone can be enhanced Meanwhile, complexity in exploiting AAS can be lowered and research and development cost can be reduced

Vertical sectorization techniques for active antenna systems

Abstract: In this paper, we study vertical sectorization techniques for multiple-input single-output (MISO) downlink active antenna systems (AAS). In the AAS, antenna beam patterns can be adjusted in each sector and multiple vertical beams can form the vertical sectorization. Since an exhaustive search based vertical sectorization algorithm requires high computational complexity to find the optimal tilt angles, we propose a low complexity vertical sectorization algorithm which is close to the performance of the exhaustive algorithm with much reduced complexity.

Active H-shaped Slot Reconfigurable SIW Antenna for Beam-Scanning

Abstract: This paper presents a new geometry of SIW "substrate integrated waveguide" active antenna based on H-shaped slots for beam-scanning applications. The phase shift and beam tilt are controlled electrically, by the state of the PIN diodes (ON/OFF) embedded in the transverse slots. This antenna allows beam scanning in 8 different directions between -45 and 45 in the same plane. The antenna is shown to be in good agreement with measured results and validate the proposed principle.

Achieving Phase Coherency and Gain Stability in Active Antenna Arrays for Sub-6 GHz FDD and TDD FD-MIMO: Challenges and Solutions

Abstract: Full-dimension MIMO (FD-MIMO) using planar active antenna systems (AAS) is considered a critical technology for fifth-generation (5G) cellular systems to improve network capacity. An AAS is typically subject to hardware impairments that negatively impact network capacity. Hence, this article focuses on impairments that cause phase and magnitude errors between radio frequency (RF) chains and shows why they are particularly difficult to avoid in practical AAS. Although previous investigations show these impairments to degrade performance, they are not useful in deriving measurable impairment margins for practical FD-MIMO deployments. Knowing impairment limits are critical for system designers to make hardware design tradeoffs such as AAS configuration, component selection, implementation complexity, and cost. Moreover, it also helps set conformance limits for critical lab verification. Therefore, the paper first investigates the impact of the impairments and derives their practical limits for FD-MIMO by explicitly considering the cumulative effects of the channel model, inter-cell interference, link adaptation, and channel aging due to feedback delays. It is shown that a lower number of digitized RF chains can be a better choice under lower impairments. Next, the sources of impairments are investigated by using measurements carried out in the lab and the field during live operation in a commercial LTE network. Phase drift from local oscillators (LO) and internal temperature variations are identified as two significant sources. The tradeoffs and shortcomings of some of the existing solutions in massive MIMO literature are discussed. Finally, in order to address the shortcomings, a novel and practical coherent LO distribution architecture and array calibration mechanism are proposed. This solution is shown to be applicable to both TDD and FDD FD-MIMO. Measurement results are provided to prove the high degree of coherency and stability achieved on a unique array architecture called high definition active antenna system (HDAAS).

Reconfigurable active reflector based on High Impedance Surface

Abstract: In this paper, the manufacturing and testing of a prototype concluding the development of a waveguide fed active antenna using an active High Impedance Surface (HIS) as main reflector are reported. The capability of such an antenna to generate various types of radiation beam (focalised, scanned…) has been demonstrated.