In today's new world of network centric warfare, where there is an ever-greater dependence on vast amounts of information that must be received and transmitted, too many antennas are a shipboard problem. They're heavy, they tend to interfere with one another, and they're unstealthy because they increase a ship's radar cross-section. They've proliferated wildly, however, because new electronic systems—radars, radio transmitters and receivers, jammers—continuously enter service.
The demand for bandwidth in an age of information warfare is not going to go away, and the solution won't be in limiting the use of the radio frequency (RF) spectrum. Ships, aircraft, even ground vehicles and individual Marine infantry—will need more bandwidth, not less.
Instead, the solution lies in making antennas that can do more than one thing at a time. Managers of Navy ship and aircraft programs are looking at pioneering work sponsored by the Office of Naval Research to develop an advanced multi-function radio-frequency concept (AMRF-C) antenna apertures. These use software to modify common apertures for multiple RF systems. The AMRF-C approach, which eliminates the need for additional hardware, would enable ship designers to dramatically pare back the microwave "antenna farms" that cover the topsides of ships now in service, while at the same time meeting future requirements, expanding the effectiveness of sensors, communications, and electronic warfare systems.
ONR scientists say that the AMRF-C effort will integrate radar and communications functions in a few sets of high-performance transmit and receive antenna apertures. Antenna growth—apart from the continuously increasing procurement and maintenance costs of individual "stovepipe" antenna types—has increased ships' radar cross-sections. The need for new antennas also has required extensive modifications in ship design to manage the added weight, as well as complex restrictions on use to minimize dangerous electronics interference. AMRF-C apertures also will integrate electronic warfare systems, which detect, jam, or deceive enemy radars and weapons.
"ONR's AMRF-C effort aims at overcoming the antenna-proliferation crisis, with all the cost, ship-design, and operational problems this crisis creates," says Dr. Joe Lawrence, director of ONR's surveillance, communications, and electronic combat division. "Instead of separate transmit and receive apertures for each of the multiple radar, communications, and electronic warfare systems, a few pairs of AMRF-C apertures would handle most microwave RF functions," he says.
The new concept addresses squarely the design, systems-engineering, and maintenance problems that confront the developers of requirements for the Navy's future surface ships.