RF Military Electronics Featured Articles

61. White Paper: Changing EW Environment Requires Even Higher RF Power 9/20/2010
    By Joe Hajduk, CEO, dB Control The theme of AOC's 47th Annual International Symposium and Convention is "Electronic Warfare in a Changing Environment." One aspect of the EW environment that's changing rapidly is the increased sophistication and persistence of threat radars. Today's threat radar detection systems must rapidly discriminate between real targets and those created by digital RF memories.
62. Changing EW Environment Requires Even Higher RF Power 9/20/2010

    The theme of AOC’s 47th Annual International Symposium and Convention is "Electronic Warfare in a Changing Environment." One aspect of the EW environment that’s changing rapidly is the increased sophistication and persistence of threat radars. Today’s threat radar detection systems must rapidly discriminate between real targets and those created by digital RF memories (DRFMs). A DRFM captures signals, digitizes them, reconverts them to their analog origin, and then rebroadcasts them, usually after modifying the signal based on a library of known emitters. The rebroadcast signal can be altered to change the target’s radar cross-section, range, speed, angle of arrival, and direction. It can also create false targets behind the target (reactive jamming) and ahead of it (predictive jamming) to trick radar detection systems into mislocating or misidentifying the target. By Joe Hajduk, dB Control

63. Phase Coherent Multi-Channel RF Synthesis 9/23/2009

    Multi-channel synthesis applications require specific performance parameters that are often overlooked with the design of single channel synthesizer systems. Performance specifications for multi-channel synthesis applications typically require channel to channel, short and long term phase coherence that is not possible with phase-locking an N-number of single channel synthesizers together. This configuration only creates a long term phase-lock ‘average’ between the outputs. Each individual synthesizer also contributes to the short term stability of this system, which is problematic with traditional phase locked synthesizers. By Jason Breitbarth and Joe Koebel, Holzworth Instrumentation

64. Configuring Phase Coherent RF Measurement Systems: From MIMO To Beamforming 8/19/2009
    Ever since the first radio waves were transmitted, engineers have continually sought new ways to utilized electromagnetic microwave signals. While RF signals have since been used for a wide variety of applications, two specific applications that utilize one common technology are wireless communications and radar. This article explains the technical requirements to configure a phase coherent RF generation or acquisition system. In addition, a step-by-step process to calibrate the phase delay between multiple RF analyzers to achieve the best possible performance is presented. By National Instruments Corporation
65. Understanding The Impact Of Spatial Effects On MIMO Wireless Channels 5/21/2009
    Spatial effects caused by angle spread, antenna radiation pattern, and the surrounding environment introduce correlations between various MIMO channels and, in the process, can substantially impact the performance of a wireless communication system. Advanced channel emulations tools, like Agilent’s PXB MIMO Receiver Tester, address this challenge through support for popular PAS distribution models and by allowing the user to enter physical antenna characteristics directly into the instrument...
66. TD-LTE Technology And Its Measurements 5/11/2009
    LTE, and particularly TD-LTE, brings new challenges to developers and to the vendors of design and test tools. New RF modulation schemes, MIMO antenna configurations, higher system bandwidths and capacity, and lower latency are just some of them. New measurement methods, including crossing the digital and RF domains, combined with a reduction in test point accessibility mean there’s a steep learning curve for both system and test developers. Successful technical introduction is a must, with analysts predicting between 30 and 80 million LTE subscribers and well over $100 billion in operator revenues within 5 years...
67. High-Speed Data Streaming For IF And Baseband Signals 4/7/2009
    As wireless technology becomes more popular, there is an increasing need to monitor the spectrum. Military surveillance, satellite communications, spectrum monitoring, and other signal intelligence applications are a few areas where this need is most apparent. However, monitoring the spectrum frequently involves the difficult task of taking data at high sampling rates for extended periods of time. This article discusses the technology of high-speed data streaming, how it is used for IF and baseband data streaming, and the hardware and software that enable acquisitions or generations at high sampling rates for hours at a time.
68. How RF Anechoic Chambers Work 3/18/2009
    A radio frequency "anechoic chamber" is a shielded room whose walls have been covered with a material that scatters or absorbs so much of the incident energy that it can simulate free space. Its origins can be traced to efforts to build aircraft which absorbed or scattered radar signals during the Second World War. Recent innovations, such as the use of ferrite tiles, have greatly enhanced performance of these chambers. Anechoic chambers may seem to operate through a bit of black magic, but the analysis of how they work is really quite straightforward. By Dr. Glen Dash, Ampyx LLC
69. Custom Filter Design 2/6/2009
    Filters are used in communication and radar systems to reject undesired signals and pass desired signals. This characteristic of filters allows them to be used at many different points in a system. This article discusses the frequency limits of lumped elements for realizing microwave filters. A specific example is given to illustrate the bandwidth limitation of lumped elements and a lumped element filter result is shown. Second, results on a 3 GHz interdigital band pass filter are shown. Third, an X-band coupled line filter is presented. By Microwave Packaging Technology, Inc.
70. Electronic Warfare: The Changing Face Of Combat 9/25/2008
    Electronic Warfare (EW) is the struggle for control of the electromagnetic spectrum — to assure that friendly forces can use the spectrum to their full potential in wartime, while denying that use to enemies. U.S. military success depends on unfettered access to the spectrum to enable electronic equipment such as radars, communication links, computer networks, and sensors to work. The purpose of this report is to discuss the challenges and opportunities facing electronic warfare today and recommend steps to secure a durable and viable electronic warfare capability for the future. By The Association of Old Crows (AOC)