Reduced-Height Array of Balanced Antipodal Vivaldi Antennas (BAVA) with Greater Than Octave Bandwidth

摘要

In the past, parameter studies of infinite arrays of balanced antipodal Vivaldi antennas (BAVAs) have identified small operating bands bounded by troublesome impedance anomalies. No definitive relationship between those anomalies and the antenna design parameters were identified. However, based on recent computational studies of the surface current distributions on the BAVA elements, our understanding of the behavior of the anomalies has increased. In particular, through proper adjustment of the antenna geometry, one of the anomalies is shifted out of the frequency band of interest. Furthermore, it was found that differential excitation of mirrored elements along the orthogonal planes of the array eliminates a second anomaly from the operating band. In this paper, all of the above observations and techniques will be discussed and active input impedance will be presented for a reduced-height (array depth D < 0.56λ of the highest operating frequency), wide-band (2.4:1) and wide-scan angle (±45°) BAVA array. Additionally, a second iteration of the design cycle has led to a single polarized BAVA phased array with 3:1 bandwidth over a slightly reduced scan volume, ±30°.