Active antenna

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

Integrated 60-GHz Antenna on Multilayer Organic Package With Broadside and End-Fire Radiation

Abstract: Existing antenna and array systems for 60-GHz wireless personal area network communications suffer from inherent poor radiation at grazing angles. This limitation is overcome in this work with a highly integrated antenna module that combines both broadside and end-fire radiators in a single multilayer organic package. Liquid crystal polymer and Rogers RO3003 are used to implement a small form factor (12.5 mm × 10 mm × 1.3 mm) antenna architecture. The co-designed broadside and end-fire antennas are characterized and measured for operation in the 57-66-GHz frequency range. Measured boresight gains of 8.7 and 10.9 dBi are achieved for the broadside and end-fire antennas while maintaining 35-45-dB isolation between both antennas. The numerically estimated radiation efficiency is found to be 92.5% and 78.5% for the broadside and end-fire elements. These antennas are orthogonally polarized and suitable for frequency reuse. Integrated circuits are mounted inside recessed cavities to realize a fully active antenna module with beam switching or simultaneous radiation. To the best of our knowledge, this is the first publication of a single package multilayer integration of millimeter-wave active antennas with both azimuth and elevation coverage.

Radio signal pickup from an electrically conductive substrate utilizing passive slits

Abstract: Embodiments of the present application relate generally to electronic hardware, computer software, wireless communications, network communications, wearable, hand held, and portable computing devices for facilitating communication of information and presentation of media. An electrically conductive substrate, such as a sheet of metal or metal alloy, for example, includes an active antenna formed by a slot or opening formed in the substrate, and also includes at least one separate passive slot or opening (e.g., a passive slit) formed in the substrate. The active antenna may be intentionally detuned from one or more target frequencies (e.g., 802.11, 2.4 GHz, 5 GHz) such that the active antenna is not optimized (e.g., is not tuned) for the one or more target frequencies. One portion of the active antenna may be electrically coupled with a ground potential. Another portion of the active antenna may be electrically coupled with a RF receiver, transmitter, or transceiver.

Tower top antenna structure with fiber optic communications link

Abstract: An intermediate frequency (IF) fiber optic communications link communicates receive and transmit signals between a distributed active antenna and base station electronics in an antenna installation. In addition, a tower top antenna structure incorporates both an RF transceiver and an optical transceiver in connection with a distributed active antenna to permit conversion between the RF signals utilized by a distributed active antenna with optical IF signals communicated over the fiber optic communications link. Complementary electronics at the base station then convert between the optical IF signals and digital IF signals for interface with base station electronics.

A Wide-Band, Active Antenna System for Long Wavelength Radio Astronomy

Abstract: We describe an "active" antenna system for HF/VHF (long wavelength) radio astronomy that has been successfully deployed 256-fold as the first station (LWA1) of the planned Long Wavelength Array. The antenna system, consisting of crossed dipoles, an active balun/preamp, a support structure, and a ground screen has been shown to successfully operate over at least the band from 20 MHz (15 m wavelength) to 80 MHz (3.75 m wavelength) with a noise figure that is at least 6 dB better than the Galactic background emission-noise temperature over that band. Thus, we met the goal to design and construct a compact, inexpensive, rugged, and easily assembled antenna system that can be deployed many-fold to form numerous large individual "stations" for the purpose of building a large, long wavelength synthesis array telescope for radio astronomical and ionospheric observations.

Downlink Vertical Beamforming Designs for Active Antenna Systems

Abstract: In this paper, we study a vertical beamforming technique for multiple-input multiple-output downlink multi-user systems. In general, the transmit antenna gain is controlled by adjusting the boresight of antennas in directional antennas, and thus the cell average rate varies according to the angle of the boresight. First, we compute the tilting angles for directional antenna systems which maximize the cell average rate. To this end, the probability density function of a three-dimensional user distribution is derived. Based on the result, we analyze the average rate gain of active antenna systems over passive antenna systems for a single user case. Furthermore, for a multi-user 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 signal-to-noise ratio assumption is presented. Also, for a multi-user passive antenna system, we provide a beamforming scheme based on a multi-sector concept. Simulation results show that the proposed beamforming schemes outperform the conventional beamforming schemes.