A Wideband Widebeam Tapered Slot Array Antenna for Active Electronically Scanned Array Antenna

Abstract

Phased arrays when mounted on aircraft and missiles will be capable of allowing only the desired signals to be received and simultaneously suppress all other unwanted ones incident from hostile sources. This in turn will make them invisible for the radars at the enemy base or on their aircraft. This paper discusses about the design of Phased array antenna for military airborne radar applications. A milllimeter wave active phased array antenna has been developed that is capable of wide scanning angle in both Eand H-planes. In order to achieve wide angle scanning over X-band frequency, a linear tapered slot antenna (LTSA) element has been designed and the resulting element is capable of scanning out to 60 o from broadside in all scan planes for a bandwidth of 11-14GHz and an active reflection coefficient less than -10 dB. Beam scanning angles of above ±45 degrees in the E-plane and ±60 degrees in the H-plane were obtained for an isolated element. An end fire array pattern with half power beamwidth of 14 degrees in E-plane is achieved over 11-14GHz frequency. This design was implemented on linear array antenna consisting of 7-elements and planar array antenna consisting of 49 (7x7) elements. The predicted performance of the antenna was verified by simulation of element patterns, array radiation patterns and S-parameter plot using commercially available electromagnetic simulator HFSS. Since the radar antenna is intended for applications where stealth is important. The antenna aperture consists many radiating elements used for beam-forming and hence through the adjustment of elemental phases steer the beam efficiently. Moreover, they are capable of rejecting all the unwanted components of the received signals while maintaining at the same time sufficient pattern gain in the desired directions. These characteristics can be implemented for stealth applications.