Active antenna

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

HBT technology and reliability for satellite applications, withinthe relatively new APOS project

Abstract: The APOS (Advanced Power Subassemblies project addresses the devices (MMIC or discrete) used in the solid state power amplifiers (SSPA) that drive the transmit active antenna. These are key devices and their electrical and thermal performances have a major impact on both the satellite and the ground terminals. GaAs-based heterostructure bipolar transistor, due to their superior power/linearity performance, could be one of these enabling devices. This aspect will be addressed within the frame of this project through three main objectives : 1)To analyse the reliability of UMS HBT technology and demonstrate it meets the requirements of the commercial satellite markets. 2)To improve the power and thermal performances of HBT by developing a power flip- chip assembly technology using thermal bumps in the active area of the power device. 3)To benchmark the developed power HBT technology by using the power MMIC in a suitable active antenna module. This project consortium is formed by Alcatel Space, that will co-ordinate the project, United Monolithic Semiconductors (UMS), Thomson-CSF, Institute for Material Research at Limburg University Centrum (1MO-LUC), DESTIN and Institut d'Electronique et de Microelectronique du Nord (1EMN).

An Advanced Sar For A European Polar Platform

Abstract: The feasibility of a spacebome SAR in C-band using a phased array antenna with active Transmit/Receive modules was demonstrated. An active antenna was selected to enable electronic beam forming while maintaining a good RF/DC power ef6ciency. Further advantages are the avoidance of high power concentrations and high power supplies, and an inherent redundancy in the case of module failures. Orthogonal transmit and receive channels are used, so that horizontally and vertically polarized signals can be transmitted and simultaneously received for polarimetry measurements. This flexible and fully programmable design allows many different modes to be applied. Resolutions from 15 m by 15m (4 looks), swath widths up to 500km, incidence angles between 200 and 500 and polarimetric measurements are possible. Performance requirements can be satisfied within the tight instrument power and mass allocations on the polar platform.

Downlink Vertical Beamforming Designs for Multi-User MISO Systems

Abstract: In this paper, we study a transmit beamforming technique for multiple input single output downlink multi-user systems with directional antennas where a transmit antenna gain is determined in three dimensional coordinates. For a multiuser active antenna system, beamforming designs to maximize the weighted sum rate are proposed by optimizing the transmit antenna gain and power allocation. Since finding joint optimal parameters requires prohibitively high computational complexity, we separate the optimization problem into two sub-problems of the vertical beamforming and the power allocation. Then a simple vertical beamforming algorithm based on a high signalto- noise ratio assumption is presented. Also, for a multi-user passive antenna system, we provide a beamforming scheme which employs a multi-sector concept. Simulation results show that the proposed beamforming schemes outperform the conventional beamforming schemes.

Espar antenna using srr

Abstract: The present invention relates to an electronically steerable parasitic array radiator (ESPAR) antenna using a split ring resonator (SPR) and, more specifically, an ESPAR antenna using an SRR, wherein an active antenna is used as a power source and an induced current is generated and radiated to surrounding parasitic elements including the SRR, which is a meta-material resonator. According to the present invention, the complexity of a mutually coupling phenomenon, which used to be generated in a traditional antenna structure, is solved in the ESPAR antenna. Particularly, directivity is realized in an MIMO system for ensuring the orthogonality of beams and a current flowing from an impedance loading circuit to a parasitic circuit can be controlled.

NB-IoT and Internet-of-Things satellite fusion antenna

Abstract: The utility model relates to an NB-IOT and Internet of Things satellite fusion antenna. The fusion antenna comprises an NB-IOT transceiver antenna (3), a row cloud receiving antenna, a row cloud transmitting antenna, a power divider, an A-path SMA-K port (7) and a B-path SMA-K port (8). Wherein the NB-IOT transceiving antenna is connected to the NB-IOT transceiving channel, the line cloud receiving antenna is connected to the line cloud receiving channel, and the NB-IOT transceiving channel and the line cloud receiving channel are combined and connected to an A-path SMA-K port (7) through thepower divider; the row cloud transmitting antenna is connected to the row cloud transmitting channel; according to the scheme, the NB-IOT transmitting and receiving antenna and the line cloud transmitting and receiving antenna are integrated in one antenna, so that the occupied space is smaller, the antenna adopts an active antenna design, the requirement of integration of a celestial body and a terminal can be met, and the requirement of separation of the antenna and the terminal can also be met.