The Need

Tightly Coupled Dipole Arrays (TCDAs) are popular due to their wide bandwidth, good scan performance, low profile, and low cross polarization. However, to realize their full potential, a wideband balanced feed is required. Compact wideband baluns are difficult to realize, and previous dipole arrays with self-contained feeds have yielded only modest bandwidths (<2:1). Wideband TCDAs have therefore typically been realized using “feed-organizers” with bulky external baluns located below the ground plane. This significantly increases the total size, weight, and cost of the array.

The Technology

Researchers at The Ohio State University, led by Dr. Jonathan Doane and Dr. Kubilay Sertel, have constructed a wideband antenna array that has better bandwidth and scanning capabilities than other arrays of similar size. This antenna eliminates the need for bulky external baluns and impedance transformers. In addition, the technology integrates the feed circuitry directly into the array volume, which reduces size, weight, and cost of the device. Their approach feeds are structured for proper TCDA operation and implement higher-order impedance matching for improved array bandwidth. This novel design exploits the natural reactant of a compact Marchand balun as an impedance matching network for each element.

Commercial Applications

• Military systems
• Smart antennas
• Data transmission

Benefits/Advantages

• The overall array height is 45 mm and the element spacing is 30 mm
• Functions over a 7.6:1 bandwidth (605-4630 MHz) at broadside and 6.6:1 bandwidth (665-4370 MHz) while scanning to ±45° in all planes
• Factor of two size reduction, a factor of five weight reduction, and more than a factor of ten cost reduction
• Ultra-wide bandwidth in exceeding 8-to-1 continuous scalable coverage (e.g. 500MHz-4GHz)