Active antenna

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

A Cross-Mode Universal Digital Pre-Distortion Technology for Low-Sidelobe Active Antenna Arrays in 5G and Satellite Communications

Abstract: A cross-mode universal digital pre-distortion (CMUDPD) technology is proposed here to linearize low-sidelobe active antenna arrays with non-uniform fixed power levels for each branch, which are desired in satellite communications with stringent requirements to minimize interference. In low-sidelobe arrays formed by nonuniform amplitude excitation, conventional digital pre-distortion (DPD) techniques require multiple feedback paths for either one-to-one or average linearization of the PAs, which increases system complexity and is infeasible for large-scale arrays. This is because the power amplifiers (PAs) usually operate in different modes where the supply voltages, bias voltages, and input power levels are different. The proposed CMUDPD method aims at solving this issue by intentionally arranging the PAs to work in different modes but with shared nonlinear characteristics. Based on the nonlinear correlation established among the PAs’ different operating modes, a single feedback path is sufficient to capture the common nonlinearity of all the PAs and determine the parameters of the CMUDPD module. The concept is explained in theory and validated by simulations and experiments using GaN PAs operating with three significantly different output power levels and two orthogonal frequency division multiplexing (OFDM) signal bandwidths.

Massive MIMO Muting using Dual-polarized and Array-size Invariant Beamforming

Abstract: A method for massive MIMO antenna muting for reducing energy consumption in 5G NR is presented and system level evaluated results is provided. By utilizing both polarizations of a dual-polarized antenna array the resulting beam shape can be kept constant as the number of active antenna elements are changed. This enables the number of active antenna elements in a large-scale antenna array to be adapted to traffic variations without affecting the system coverage. Hence the energy consumption associated with having a large antenna array can be avoided whenever the additional performance is not required. The results indicate that massive MIMO antenna muting can reduce the base station energy consumption with up to 30% without significantly degrading the system performance and user throughput. Results for dynamically down scaling of massive MIMO array sizes from 128 single polarized antenna elements to 64, 32 and 16 active antenna element configurations are presented.

Measurements of Antenna Systems in Reverberation Chamber: A Review

Abstract: This paper presents a review of various measurement techniques of antenna systems in the reverberation chamber (RC). RC-based metrologies of both passive antennas as well as active antenna systems are presented and discussed.

A Wide-band Slot-based Frequency Agile Yagi-Like MIMO Antenna System

Abstract: In this work, we propose a wide-band slot-based frequency agile 2-layer Yagi-uda-like multiple-input-multiple-output (MIMO) antenna system. The MIMO system consists of 4 identical pentagonal slot-line based active antenna elements reactively loaded with varactor diodes to achieve frequency reconfigurability. The proposed antenna could be tuned over a wide frequency band from 1.5-2.1 GHz. To achieve Yagiuda-like directional characteristics of a slot antenna, a parasitic metallic reflector layer was used below the substrate. This helped in suppressing the back-lobe radiation and thus a front-to-back ratio (FBR) of 5-13 dB is achieved within the entire frequency band of operation. The proposed 4-element design is compact with an overall size of $100\times 100 \times 20$ mm 3, and a reflector size of $\textbf{110}\times \textbf{110}$ mm 2. The antenna system also shows good MIMO performance with high port isolation and very low envelope correlation coefficient (ECC) values within the operational band.

Diodes Loaded Active Microstrip Antennas Design and Analysis of Diodes Effects on Active Antennas For Rf Wireless Receiver-Transmitter Systems

Abstract: This paper is presentation of designed different diodes loaded active model dissimilar geometries of micro strip patch antennas. As known, mikrostrip patch antennas have complex impedance and its impedance changes with frequency. Because of this, imaginer part of micro strip patch antennas is minimized by effect of diodes having capacitive reactance thus maximum power radiating is occurred. The aim of this project is to present different diodes loaded patch antenna for ISM 2.4 Ghz and to indicate active antenna performance according to influence of locations and dc biasing of diodes then to compare the antenna parameters of passive models. Besides, this project is used three types of diodes which are schottky Barrier diodes, silicon variable capacitance diode and tuner diode and four diodes whose are bas70, bas83, bb619 and bb721. The simulation programmer is AWR Design Environment Microwave Office 2007 (MWO) whose analysis meted is moment (Mom). Finally, the antennas that are projected are ready condition for LAN application or wireless RF receiver-transmitter systems. Return loss of designed antennas are between -25.54 dB and -36.17 dB. Gain does not change a lot but results of VSWR and Input impedance is satisfactory when comparing the passive model's results.