Traveling-Wave Antenna (TWA) Array as a Thin Multioctave Planar Phased Array (MPPA)

Multioctave Planar Phased Arrays (MPPA) have advanced rapidly since 2000. Today, MPPA technology and its market needs appear to be nearing a point of convergence. This paper reviews the history of thin MPPAs, which exclude the Vivaldi antenna type, and presents modern planar Traveling-Wave Antenna (TWA) array as a thin MPPA. The differentiating features of modern planar TWA array from other thin MPPAs, and its potential high performance and other advantages, are discussed. Certain controversies in the theory and measurement of MPPAs are also reviewed and clarified. A planar TWA array design, with SEG breadboard demonstration, is presented to show potential performance of low VSWR, high-efficiency (low loss), scan angle <= 60 degrees off broadside, over a 6:1 bandwidth and beyond.