Antenna Systems & Technology - Winter 2011 - (Page 4)

EDITOR’S CHOICE Thirteen 12-meter antennas manufactured by General Dynamics SATCOM Technologies have been successfully installed at the 16,500-foot-high Chajnanator plateau in Chile, home to the Atacama Large Millimeter/submillimeter Array (ALMA) astronomical observatory. Located in the Andes mountains, the 115-ton, highly specialized antennas form part of an 11-mile-wide international astronomy project. When it is completed in 2013, scientists will use the observatory to study portions of the universe at a level of detail that is beyond what current astronomical technologies provide, studying the origins of galaxies, stars and planets. Now, in a preliminary step, the General Dynamics-built antennas are being linked together for the first time with others made in Europe and Japan to begin operating as a single radio telescope, enabling initial scientific experiments or ‘early science.’ One toprated science experiment will use ALMA to unearth the behavior of about 50 of the most massive black holes in the universe previously hidden in the dusty material of their galaxies. “The installation of the General Dynamics antennas on the Chajnanator plateau represents a significant achievement for the North American portion of the ALMA project,” said Brian Schrader, senior director of Engineering and Major Projects for General Dynamics SATCOM Technologies. “We’ve provided the majority of the antennas now allowing scientists to pursue projects that use ALMA’s eyes to make large leaps in exploration.” “With ALMA poised to commence historic early science observations using at least 16 of its final 66 antennas, it is already the world’s most powerful astronomical observatory at millimeter wavelengths. We’re grateful to the entire North American ALMA antenna team, of which General Dynamics SATCOM Technologies is an integral part, for working so hard to make this day possible,” said Mark McKinnon, North American ALMA project director at the National Radio Astronomy Observatory (NRAO). Antennas Enable ‘Early Science’ for Radio Telescope the September 11th terrorist attacks, consumers have overloaded private data networks like Verizon, AT&T and Sprint by calling loved ones and posting videos to the Internet. As a result, people in urgent need of emergency assistance have trouble getting through to help. The BATS BTS-3300 (with GPS) plays a critical role in New York City’s new wireless emergency response network. The system is able to automatically locate, lock in and track wireless broadband connections among mobile command centers and remote locations throughout the entire NYC coverage area within eight minutes. The BATS BTS-3300 mobile communication unit integrates with the New York City Wireless Network and provides 110 megabit throughput to New York City’s emergency services wireless network. Access points on the NYC-Win are equipped with 24 hours of backup power, vital for communications to continue to run even during blackouts. New York’s new wireless network is already inspiring other cities and states to consider how their communications systems withstand emergency situations. New Avago Technologies Variable Gain Amplifier Modules Deliver Linearity for Cellular Base Stations Avago Technologies has released a high-linearity variable gain amplifier (VGA) module for base transceiver station (BTS) applications. The new small-footprint ALM-81224 VGA module replaces existing discrete solutions, providing significant board space savings and shortening design cycle time. Operating in a broad frequency band from 1,450 MHz to 2,750 MHz, the module addresses cellular BTS automatic gain control (AGC) and temperature compensation circuitry applications. The ALM-81224 VGA module’s linearity performance provides the ability to distinguish between wanted and spurious signals that are closely spaced. Available in a 6.0 mm by 6.0 mm by 1.0 mm package, the module offers low current consumption of 383 mA. The module’s input is fully-matched to 50 ohms and output match can be tuned for optimal performance at a particular frequency band within the operation range, minimizing the need for external matching components and making the solution easy to use. The ALM-81224 module leverages the company’s proprietary 0.25 µm GaAs Enhancement-mode pHEMT process to achieve robust RF performance. It delivers a dynamic range of 38 dB under 0 to 3.3 V control voltage. Using a single DC voltage input pin to achieve gain control, the module provides a high maximum gain of 23.8 dB typical. Broadband Antenna Tracking Systems Brings Better Emergency Communications to NYC To improve communications during emergencies, New York City recently created its own wireless data network called the New York City Wireless Network (NYC-Win). Innovative solutions from Broadband Antenna Tracking Systems (BATS) are a key part of the new infrastructure. In the aftermath of tragedies such as Hurricane Katrina and 4 ANTENNA SYSTEMS & TECHNOLOGY WINTER 2011 WWW.ANTENNASONLINE.COM http://WWW.ANTENNASONLINE.COM

Table of Contents for the Digital Edition of Antenna Systems & Technology - Winter 2011

Antenna Systems & Technology - Winter 2011
Editor’s Choice
Reducing Measurement Times and Improving Economic Competitiveness for Antenna and RCS Applications
Troubleshooting in Mediumwave Multiplexing Antennas
Design Considerations in the Selection of High Frequency Materials for PCB Base Station Antennas
Antennas
Distributed Antenna Systems
Wireless Communication
Industry News
Wireless Network Planning from the Desktop Using High Resolution 3D NEXTMap Digital Surface Elevation Data

Antenna Systems & Technology - Winter 2011