scispace - formally typeset
Search or ask a question
Topic

Active antenna

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


Papers
More filters
Patent
11 Oct 2019
TL;DR: In this article, an active antenna unit and an antenna unit for a base station are described, where the active antenna is embedded in a sealing part and the antenna substrate is pressed on the sealing part through a fastener inserted into the first assembling hole, and the sealing groove comprises first groove sections which extend in the length direction of the supporting end surface.
Abstract: The invention discloses an active antenna unit and an antenna unit for a base station. The active antenna unit for the base station comprises a housing and a base station antenna; an antenna substrateis supported on a supporting end surface with the side wall far away from one end of the bottom wall; a first assembling hole and a sealing groove are formed in the supporting end surface; the activeantenna unit comprises a sealing part which is embedded in the sealing groove; the antenna substrate is pressed on the sealing part through a fastener inserted into the first assembling hole; the sealing groove comprises first groove sections which extend in the length direction of the supporting end surface and are positioned on the two sides of the first assembling hole, and a second groove section which is wound on the periphery of the first assembling hole and is connected with the two adjacent first groove sections; and the shortest distance between the extension line of the middle lineof each first groove section and the center of the first assembling hole is smaller than one sixth of the groove width of each first groove section. The supporting end surface is uniform in stress.

2 citations

Patent
16 Feb 2018
TL;DR: In this paper, an on-vehicle active antenna device and an on -vehicle unit, on vehicle active antenna devices, where the receiving and dispatching antenna that is used for receiving and sending signal for gating receive chain or transmit chain's radio frequency switch module was used for the enlarged module of enlargeing received signal or sending a signal, be used for with upper device connect so that upper device is handled receiving signal or receipt upper device provides send a signal.
Abstract: The utility model provides an on -vehicle active antenna device and on -vehicle unit, on -vehicle active antenna device wherein, including the receiving and dispatching antenna that is used for the receiving and sending signal for gating receive chain or transmit chain's radio frequency switch module is used for the enlarged module of enlargeing received signal or sending a signal, be used for with upper device connect so that upper device is handled received signal or receipt upper device provides send a signal, and do the active antenna device provides the next biasing ware of power, still includes control module, control module is used for the basis the mains voltage control that the next biasing ware provided the RF switch. Adopt the utility model discloses, can effectively improve theholistic emission efficiency of system, effectively reduce the noise performance of system's link, promptly effective improve equipment's receiving performance.

2 citations

Proceedings ArticleDOI
22 Apr 2019
TL;DR: This module can be used to build a large hierarchical digital phased array through synchronize four LO signals at system level through synchronizing four LO messages at systemlevel.
Abstract: This paper describes the design and implementation of an X-band scalable $4\times 4$ element-level digital phased array module. The module consists of sixteen active antenna elements. Each of these elements includes one custom CMOS RF SoC and one custom GaAs switch frontend IC. The RF SoC is implemented using a 65-nm CMOS process. The T/R Switch frontend IC is implemented in a $0.15-\mu \mathrm{m}$ GaAs pHEMT process. The module also includes a digital signal processor implemented in an FPGA SoC device, and the required power supply subsystems. This module can be used to build a large hierarchical digital phased array through synchronizing four LO signals at system level. The built array serves as a tool for researching software-defined phased array radar and communication systems. This paper reports initial test results of this module. This module achieves a state-of-the-art 42-mm scalable tile thickness.

2 citations

Patent
Weishan Lu1, Tao Wu1
19 Jun 2015
TL;DR: In this article, the authors provided a single radio frequency double-stream transmission apparatus, which includes a radio frequency link, a reactance control circuit, a parasitic reactor, an active antenna and an even number of parasitic antennas.
Abstract: Embodiments of the present disclosure provide a single radio frequency double-stream transmission apparatus, wherein the apparatus includes: a radio frequency link, a reactance control circuit, a parasitic reactor, an active antenna and an even number M of parasitic antennas, wherein M is larger than 2; the radio frequency link is configured to generate a radio frequency signal; the active antenna is connected with the radio frequency link, the parasitic antennas are respectively connected with the parasitic reactor, the distances from the parasitic antennas to the active antenna are the same, and the radian between adjacent parasitic antennas is 360 M  degrees ; the parasitic reactor may be adjusted by the reactance control circuit to make the reactance values of any pair of parasitic antennas in mirror symmetry via the active antenna be different and the reactance values of the rest pairs of parasitic antennas in mirror symmetry via the active antenna be equal respectively.

2 citations

01 Jan 2017
TL;DR: Martin et al. as mentioned in this paper investigated the RF rectification of the plasma potential and the resulting cross-field flows that form due to an active RF antenna, and they showed a plethora of problems that must be solved for successful ICRH operation, even at low antenna powers.
Abstract: Author(s): Martin, Michael John | Advisor(s): Gekelman, Walter | Abstract: Ion cyclotron resonance heating (ICRH) systems are critical components of current and future tokamak experiments aimed at producing nuclear fusion energy. During ICRH a host of deleterious effects occur, including increased heat flux to plasma facing components and modification of launched wave power. A suspected root cause of these effects is the radio frequency (RF) rectification of the plasma potential. Interest in the antenna scrape-off layer (SOL) region has drawn increasing interest, as it is recognized that mitigating these effects is necessary to achieving fusion power. This dissertation investigates the RF rectification of the plasma potential and the resulting cross-field flows that form due to an active RF antenna. The experiment is performed in the Large Plasma Device (LAPD) utilizing a fast wave antenna and RF amplifier system developed for these studies. The RF system is capable of 150 kW output power for a 1 ms pulse that is repeated at the 1 Hz repetition rate of the LAPD plasma discharge. Upon application of the RF pulse to the antenna, the DC plasma potential, measured with an emissive probe, dramatically increases in certain spatial locations by a factor greater than 10 Te. The largest plasma potentials are observed at locations magnetically connected to the top and bottom of the antenna, and they exist only in the private SOL created between the antenna and a limiter placed 3.6 m away along the LAPD axis. The DC rectified potentials scale linearly with the antenna current over a factor of 12x in the applied current. These DC potentials increase plasma materials interactions (PMI), resulting in the sputtering of antenna materials whose presence is detected in the bulk plasma by the coatings that develop on probe diagnostics. The DC rectified potentials persist in the plasma long after the RF current in the antenna has rung down on the same time scales as the change in the density. At the top and bottom of the antenna are circular flows, often called convective cells. These ?i?½?? flows arise due to the spatial variation of the RF rectified potentials across the background magnetic field. The maximum strength of the electric field causing these flows wasfound to scale quadratically with antenna current, giving rise to drift velocities that are a substantial fraction of the local sound speed, v_drift/c_s ≈ 0.8. These flows have a dramatic effect on the density, which increases in the SOL and develops poloidal asymmetries in the plasma region magnetically connected to the front face of the antenna. The convective cells cause a density depletion at the antenna midplane that increases with antenna current until a threshold current. The 2-D density modification is physically consistent with the calculated ?i?½?? flows. These results show a plethora of problems that must be solved for successful ICRH operation, even at low antenna powers. These deleterious effects may be mitigated by antenna designs that reduce rectified potentials and utilize PMI-resilient materials. The saturation in the density depletion at the antenna midplane suggests methods for targeted density injection may be successful in improving antenna wave coupling.

2 citations


Network Information
Related Topics (5)
Antenna (radio)
208K papers, 1.8M citations
88% related
MIMO
62.7K papers, 959.1K citations
79% related
Amplifier
163.9K papers, 1.3M citations
78% related
Resonator
76.5K papers, 1M citations
78% related
Transmitter
61.9K papers, 874.2K citations
77% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202148
2020113
2019123
201898
201789
2016102