A Wide Scan Phased Array Antenna for A Small Active Electronically Scanned Array Antenna

Abstract

ABSTRACT newlineThe main objective of this research work is to design a miniaturized, wide-beam newlineVivaldi antenna with a wide-scan capability over an approximately 10% bandwidth newlineat the X-band frequency of the airborne radar antenna. This Vivaldi antenna is a dual newlinelayered exponentially tapered slot antenna (DETSA) which satisfies the return loss newlineresponse lower than 10 dB over the frequency band of 8-12 GHz. Stripline to slotline newlinetransition is used to feed the DETSA element and coupled electromagnetically by newlineexponential tapered transitions. This research work mainly focuses towards the newlineimprovement of gain and directivity over the desired frequency band of operation. newlineDETSA is capable of scanning to 120o from broadside in H- and E-planes. The half newlinepower beam width of DETSA is greater than 120o in the two principal planes. The newlineantenna is optimized with a total size equal to 14.2x24.1x1.4 mm3 and is capable of newlineachieving the desired bandwidth experimentally. newlineThe research work has been extended to design and develop a 9-element newlineuniform linear array with the optimized dimensions which is operating in X-band newlinewith a half power beam width of 11o and side lobe levels smaller than 13 dB with a newlinegain of 13 dBi. The 9-element array and feeding network based on T-junction power newlinedividers were employed to compose the linear array. The power distribution among newlinethe radiating elements is realized using a uniform distribution. The 9-element array newlinewas fabricated and measured over X-band frequency. The designed antenna array is newlinesuitable for X-band airborne radar applications in combat aircraft. Further, 81- newlineelements uniform planar array has been designed with optimized dimensions; newlineoperating in the X-band frequency with a half power beam width of 11o and side lobe newlinelevels 13 dB with a gain of 24 dBi. The uniformly illuminated array beam pattern has newlinebeen steered with different scan angles over the scan volume -60o to +60o and newlinemultibeam scan patterns achieved from the array can scan over the desired scan newlinevolume of ±60o in E-plane and more than ±55o in