A New Efficient Array Architecture for Small L-Band Secondary Surveillance Radars with Reduced Number of Elements

ABSTRACT In this paper, a new and more efficient array architecture for small Secondary Surveillance Radar (SSR) antennas is presented. The architecture uses a side element for the generation of the Control (CTRL) beam as a new proposed method and is applied on a 7-element 1.5-m SSR antenna array. All three required patterns for secondary surveillance radar containing SUM, DIFF, and CTRL are designed and implemented in an integrated one-sheet feed network. The array antenna uses Taylor distribution for SUM port, obtaining 16 dBi and 16.7 dBi of gain at 1030 MHz and 1090 MHz, respectively, and a side lobe level of 23 dB at the measurements. It is demonstrated that the last side element at the edge is the best choice for CTRL pattern with respect to the final pattern shape, maximum achievable gain, and easy implementation in this small array architecture, which results in more than 60% of aperture efficiency. The simulation and measurement results are in acceptable agreement.