Active antenna

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

First Commercial Hybrid Massive MIMO System for Sub-6Hz Bands

Abstract: Massive multiple-input and multiple-output (MIMO) has been the subject of interest in both industry and academia for the past few years. Massive MIMO refers to the use of a large number of antennas typically at the base station (BS) to serve multiple user equipment (UE) simultaneously to deliver reliable and high data throughput. Two basic architectures have been considered in the literature. First is a full digital massive MIMO where all the beamforming and precoding is performed digitally in baseband and a radio frequency (RF) chain is required for every antenna element. In the second architecture referred to as hybrid massive MIMO, beamforming and precoding are done in two stages, digital precoding over fewer digital ports followed by analog beamforming across large number of antenna elements. In this paper, we provide a comparison of implementation challenges for each approach. We introduce the High Definition Active Antenna System (HDAAS), a novel scalable architecture to implement a hybrid Massive MIMO system. This design philosophy is used to build BeamCraft500, which we believe is a first commercial hybrid 3D beamforming system operating at 2 GHz. We also present results from one of the field trials in a live LTE network that validate the stability and performance of the system under real world conditions.

Reconfigurable scan‐beam hollow patch reflectarray antenna loaded with tunable capacitor

Abstract: In this article, the design concept of an active reconfigurable reflectarray antenna has been proposed and tested. The elementary radiators are hollow patch element loaded with varactor-diode device in which the reflected phase can be varied. This phase alteration is based on the variation of the diode capacitance which can be achieved by varying the biasing voltage of the active varactor device. By activating these varactor devices, the phase of each antenna element in the array configuration can be adopted dynamically, and consequently, its radiation beam direction can be reconfigured. The advantage of the MEMS switches is the complexity of the integration and continuing beam scanning capability. The reflectarray incorporating active elements has been built and tested at 6.0 GHz. Narrow band multifrequency shared aperture is demonstrated theoretically and experimentally. The performance of the proposed active antenna is excellent, which pioneers the design of arbitrarily reconfigurable antennas. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 367–374, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24050

Method and system for sharing antenna by multiple operators and radio-frequency digital conversion unit

Abstract: A system for sharing an antenna between multiple operators is provided. The system includes a radio frequency and digital conversion unit and an active antenna. The radio frequency and digital conversion unit is configured to convert a radio frequency signal of each radio frequency module into a digital signal, and send digital signals of a same sector to an active antenna corresponding to the sector. The active antenna is configured to perform at least one of vertical beam forming processing and horizontal beam forming processing on received digital signals according to a signal transmitting parameter that is set for each operator, convert the processed digital signals into radio frequency signals, and then transmit the radio frequency signals from an air interface.

Control of mode-switching in an active antenna using MESFET

Abstract: New techniques of realizing mode-switching in an active antenna by using a MESFET are presented. Two types of control circuits are discussed. One is the control circuit using the reactance variation of the MESFET and the other is the control circuit using the resistance variation of the MESFET. The design of these two control circuits is discussed and the beam-switching phenomena of the antenna using these control circuits are compared. Important characteristics such as antenna patterns, operating frequencies and the insertion loss of the control circuits are also compared and discussed. >