Since the birth of radio, electronics has played a key role in modernizing the armed forces and keeping the military at the forefront. Consequently, this effort has continued unabated. Therefore, it is not surprising to see that Department of Defense's (DoD) investment in basic research and technology has only grown with time. However, its effort to tap the latest advances made in the semiconductor industry has only mushroomed in the last decade or two.

Now, the ongoing unconventional war against terrorism poses new threats and challenges to the military. In addition to bringing older and modern systems to new levels of unprecedented performance, efforts are also under way to develop innovative systems with novel functions and capabilities never before imagined. In the past, such efforts have spawned systems like the Global Positioning System (GPS), night-vision devices and unmanned aerial vehicles (UAV).

To keep the readers abreast of the developments on the RF and microwave/millimeter-wave front, RF Design's Defense Electronics has invited three vendors to highlight advances made in their respective technologies and to show how they affect military systems in general.

The first feature sheds light on problems of RF interference in systems like radars, electronic warfare systems and communications equipment. Increased use of microwave electronics by today's military equipment carries with it the increased potential for RF interference. The impact of RF interference on military microwave electronics creates major problems, causing errors in targeting, reducing system efficiencies and limiting operating capabilities. Microwave-absorbing materials help eliminate or reduce to manageable levels most problems involving RF interference.

The use of microwave-absorbing materials by the military community dates back to the 1940s, spawned by the introduction of radar. The military community describes microwave-absorbing materials with the acronym “RAM,” for radar-absorbing materials. Microwave absorbers are materials specifically designed to attenuate or absorb microwave energy. In the article, “Microwave Absorbers Manage Military Electronics RF Interference,” by Jack T.Gear of Emerson & Cuming Microwave Products Inc., the author delineates various types of microwave-absorbing materials and provides guidance in selecting a microwave-absorbing material for your specific application.

The second article discusses the data conversion requirements for today's digital-centric military and aerospace systems. As digital signal processing gets more sophisticated in modern and future mil/aero systems, the role of data converter devices becomes even more prominent. In this article, “Designing Military Data-conversion Systems Involves Multiple Tradeoffs,” by Mark Looney and Steve Reine of Analog Devices, the authors highlight key parameters system designers must take into consideration when selecting analog-to-digital and digital-to-analog converter (ADC and DAC) devices for high-performance military/aerospace communications and radar systems.

Development of these data-conversion systems requires careful consideration of many different parameters that represent a “data conversion trade space.” An example of the data conversion trade space can include critical performance parameters such as sample rate, input bandwidth, resolution, dynamic range, noise, linearity, power dissipation and support circuitry (analog front-end, clock drive, digital demux, etc). In addition to electrical performance requirements, many other factors, such as package size/pin-out, thermal management, unit cost, project risk, component screening, and reliability can play a significant role in the development of data conversion systems.

Lastly, “Handheld Instruments Aid Shipboard RF Measurements,” by Steve Thomas of Anritsu Company, shows how advanced portable instruments are addressing the daunting challenges of making RF and microwave measurements aboard modern Navy ships — ships that present a complex electromagnetic environment generated by onboard instruments like radar, electronic warfare, electronic countermeasures, and communications and fire control systems. Additionally, these onboard, sophisticated electronic gadgets are confined to a smaller space with limited accessibility. Besides offering performance levels with immunity to a high level of electromagnetic energy, the new line of portable instruments are also easing the task of reaching the most inaccessible areas onboard.