Advanced science.  Applied technology.


Novel SwRI-developed antenna array wins 2023 R&D 100 Award

August 29, 2023 — Novel Southwest Research Institute-developed direction-finding technology has won a prestigious R&D 100 Award. R&D World Magazine has recognized SwRI’s Wideband Conformal Continuous-Slot Antenna Array as one of the 100 most significant innovations for 2023.

“Southwest Research Institute strives to uncover innovative solutions to complex problems,” said SwRI President and CEO Adam L. Hamilton, P.E. “I am very proud of the work SwRI does and pleased to know this technology, which will provide significant support to naval operations, has been recognized as one of the most important innovations of the year by the R&D 100 Awards and their esteemed judges.”

SwRI’s state-of-the-art Wideband Conformal Continuous-Slot Antenna Array technology provides naval ships with high-performance, high-frequency radio frequency direction-finding (DF) and signal acquisition while conforming around shipboard-supporting mast structures. Modern-day DF systems determine the direction of enemy combatants and provide situational awareness and serve to locate emergency transponders for search-and-rescue operations.

“The operating frequency and bandwidth of modern radio frequency, or RF, communications signals are trending increasingly higher, outpacing the performance of modern direction-finding, or DF, antennas,” said SwRI Staff Engineer Patrick Siemsen, who led the project. “Current DF antennas must maintain precise electromagnetic spacing between array antenna elements to prevent grating lobes or ripples in the beam-formed antenna patterns, which can cause performance issues.”

Traditional shipboard high-frequency DF antennas are typically mounted at the top of a mast due to inter-antenna element spacing requirements or situated on a yard arm off the side of the mast. Antennas in these placements can experience structural blockages, reduced sensitivity and degraded performance. 

The Wideband Conformal Continuous-Slot Antenna Array, released as part of SwRI’s AS-750 family of advanced antenna arrays, overcomes the performance issues commonly encountered at higher frequencies. The array was designed using electromagnetic modeling software and takes inspiration from an unorthodox concept for a wideband antenna array originally conceived by electronics engineer Harold Wheeler in 1948, which until now was largely theoretical.

“Our AS-750 antenna arrays use a series of continuous slot antennas with closely spaced antenna feeds around the perimeter array,” Siemsen said. “The close spacing is possible through symmetrical, dual-ring microstrip corporate feed networks. We can conform the antenna array around the support mast without losing processing performance, and the design allows higher-priority navigational and threat-warning systems to be mounted above it for optimal performance by the communication intelligence systems.”

The SwRI Wideband Conformal Continuous-Slot Antenna Array enables existing and future naval platforms to support the need for communications intelligence systems to perform the previously unachievable high-performance signals processing of increasingly sophisticated ultra-high and super-high frequency signals. The antenna array is only seven inches high and requires a fraction of the space required by comparable arrays without sacrificing the durability necessary for the demands of a naval shipboard environment.

Though designed for naval shipboard signals intelligence applications, the AS-750 antenna arrays are suitable for other uses and installations where similar mounting restrictions apply or when low-profile packaging is desired. The SwRI team is investigating other applications for the antenna arrays, including airborne and land-based uses.

Now in its 61st year, the R&D 100 Awards are among the most prestigious innovation awards programs, honoring the top 100 revolutionary technologies each year. R&D World Magazine received entries from 15 different countries and regions this year. Past recipients hail from research institutions, academic and government laboratories, Fortune 500 companies and smaller organizations. The 2023 R&D 100 winners will be honored at a special gala banquet on Nov. 16, 2023, in San Diego, Calif. Since 1971, SwRI has received 52 R&D 100 awards.

For more information, watch a video at, visit Signals Intelligence Solutions, or contact Jesús Chávez at +1 210 522 2258, Communications Department, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166.