Dielectric Free Wide Scan UWB Low Cross-Pol Metallic Vivaldi Antenna for Active Phased Array Radars

Abstract

Tapered slot antennas (TSA) or Vivaldi antennas (VA) arrays studied extensively for many decades have proved to be a potential candidate for wide band (WB) and wide scan (WS) phased array antennas. Earlier analyses have shown that their WB performance suffers from few impedance anomalies due to the coupling associated with surface waves in dielectric substrates and the inter-element gaps in an array. Many researchers have dealt with these problems, proposed metallic TSAs or VAs with elements joined along one of the principal planes (usually E-plane) demonstrating wideband and wide scan capabilities. The author complements the existing research and presents an ultra- WB (UWB), wide beamwidth (HPBW), low cross-polarized (x-pol) and of comparatively smaller size metallic VA (MVA) structure with slotline-to-coax-balun feed. Aluminium metal is used for fabricating monolithic linear arrays positioned together to form a 2D-array. The thickness of MVA reduces the inter-rows gap, thereby removing the impedance anomalies. A Floquet model-based analysis with FEM is used for analysing MVA’s performance in an array environment validated with measurements in an 8 × 8 finite array environment. The measurements demonstrate wide beamwidth (>90^o;120^o), impedance and pattern bandwidth of 127% and 60%, gain >3dBi and x-pol level <−20 dB.

KEYWORDS:

• Active phased array
• Vivaldi antenna
• Wide band
• Wide scan

ACKNOWLEDGEMENT

The author would like to acknowledge the mechanical engineering and the antenna measurement team at LRDE for their extensive support. The author would also like to acknowledge the Director, LRDE for his constant support and encouragement during the work.

Additional information

Notes on contributors

Ashutosh Kedar

Ashutosh Kedar (M’10–SM’13) received his PhD, MTech and MSc in elect, microwave elect and physics in 2003, 1998 and 1995, respectively, from the University of Delhi, India.

He taught and researched at the University of Delhi and has been working as a radar scientist in LRDE, Bangalore since 2003. He gives lectures on radar, antennas and phased arrays and has published approximately 60 papers. He is reviewer of many international journals like IET, PIERS, ACES, IEEE, etc. He is listed in Asia’s who’s who. He received technology group awards for 1^st indigenous active phased array radar and 1^st four-walled active phased array radar development in the country in 2010 and 2018, respectively. He received the best paper award in ICMARS and ATMS’18. His research interests include CEM, phased array antennas and radars. Corresponding author. E-mail: [email protected]