Active antenna

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

Active Antennas for Cubesat Applications

Abstract: Timothy S. Fujishige 16 Annual/USU Conference on Small Satellites Abstract—An active antenna known as a grid oscillator is presented for use onboard the University of Hawaii’s CubeSat. It operates at high frequencies that will be able to facilitate future, more data-intensive missions. The device uses an efficient power-combining scheme packaged in a compact, low-profile structure that can be mounted on the side of a cube. The active antenna consists of an array of transistors directly embedded into a planar radiating structure. An infinitearray approximation is used to simulate the grid design in CAD programs. Various mounting schematics are presented for the grid oscillator that is currently being fabricated with a desired oscillation frequency of 5.85 GHz.

Low cost 60 GHz RF front end transceiver integrated on organic substrate

Abstract: This paper presents, for the first time, a low cost, 60 GHz, RF front-end Tx/Rx integrated with a Yagi-Uda antenna array on organic Liquid Crystal Polymer substrate. The Tx/Rx module consists of a GaAs LNA, PA and a Single Pole Double Throw (SPDT) switch wirebonded on a single, multilayer substrate. The array was designed for operation at 60.6 GHz with a gain of 12.1 dBi. The radiation pattern measurements were conducted and showed an active antenna gain of 31.8 dB for the receiver and 21.6 dB of gain for the transmitter. It demonstrates 19.7 dB and 9.5 dB of added gain from the integrated receive and transmit modules respectively. The array has 1 and 3 dB deviation in gain in receiver and transmitter modules respectively from 55–63 GHz.

Electronic beam steering of active antenna arrays

Abstract: Electronic beam steering of an active antenna array is demonstrated using active inverted stripline patch antennas. The technique uses DC bias to change the self-oscillating frequencies of individual active antenna elements and impose an injection-locking phase shift between active antenna elements. The phase shift allowed 15° of electronic beam steering.

Modular millimeter-wave radio frequency system

Abstract: A modular millimeter-wave radio frequency (RF) system comprises a plurality of active antenna arrays for receiving and transmitting millimeter-wave RF signals; and a plurality of RF sub-modules for performing at least up and down conversions of intermediate frequency (IF) signals and controlling the plurality of antenna arrays, each of the plurality of RF sub-modules is connected to an antenna array of the plurality of antenna arrays, wherein the plurality of RF sub-modules are chained to each other through a first transmission line and one of the plurality of RF sub-modules is connected to a baseband module through a second transmission line, each of the first transmission line and the second transmission line transfers a multiplexed signal including an IF signal, a local oscillator (LO) signal, a control signal, and a power signal

Security Enhancing Spatial Modulation Using Antenna Selection and Artificial Noise Cancellation

Abstract: In the multi-input multi-output (MIMO) wireless communication systems, spatial modulation (SM) has wide application prospects as a novel modulation technology. In this paper, a new secrecy enhancement scheme for the SM system is proposed, in which the number of transmit antennas $N_{a}$ is not a power of two. The transmitter first chooses $N_{t}$, which is a power of two, antennas from $N_{a}$ transmit antennas for SM. Then, the transmitter transmits, in addition to the information symbols, an artificial noise (AN) through the active antenna. At the same time, another one of the remaining $N_{a}-N_{t}$ antennas is activated randomly by the transmitter to transmit another AN. The ANs are designed by exploiting the channel state information (CSI) of the legitimate channel, and then the ANs can only be cancelled at the legitimate receiver while the passive eavesdropper will suffer the interference of them. Furthermore, the security performance of the proposed scheme is also analyzed. Numerical results verify that our proposed scheme is able to achieve a satisfactory performance.