Hybrid-fed Enhanced Gain Circularly Polarized Shared Aperture Antenna Array for X/K-band Airborne Synthetic Aperture Radar Applications

This work presents the design of an X/K-band Shared Aperture Antenna (SAA) 36-elements (6 × 6) planar array antenna with good gain and cheap cost for airborne synthetic aperture radar (ASAR) systems. Feed network complexity and size are reduced by using a Chebyshev-amplitude distribution of 25 dB SLL in a series-feed centre fed open stub (SFCFOS) array. X-band and K-band frequencies of 9.65 GHz and 21 GHz are used in this proposed SAA design on a single-layer printed circuit board (frequency ratio of 1: 2.176). (PCB). Chebyshev distribution can be used to manage minimum side lobes in K-band designs. The width of each patch in the linear array with left and right symmetry may be used to alter the amplitude. To meet a 25° scan angle requirement, a 50 Ω microstrip line with 0.7λ spacing is employed in between the patches There is a 10.36/1.45 percent matching impedance bandwidth in the X and K-bands, which is in agreement with the calculations. A good efficiency of greater than 85%, SLL of (X/K-bands: 18.9/25 dB), and gain of (X/K-bands: 24.2/17.4 dBi) are also included.