A new optimized quadrant pyramid antenna array structure for back lobe minimization of uniform planar antenna arrays

In this paper, a new optimized quadrant pyramid antenna array (O-QPAA) structure is proposed for back lobe minimization of planar antenna arrays (PAA). Based on the PAA size, it is thought to be formed of a number of concentric co-planar squared antenna arrays (SAA) or rectangular antenna arrays (RAA) placed in the X-Y plane. Initially, to construct a non-optimized QPAA, these concentric SAAs or RAAs are distributed vertically along the Z-axis with uniform vertical spacing. Thereby, the QPAA is treated as a hybrid of uniform SAAs or RAAs and a linear antenna array (LAA). However, the QPAA may have a main beam and back lobe of the same amplitude. To address this issue, the O-QPAA structure is proposed, which allows for the minimization of the back lobe while still controlling the QPAA pattern features such as side lobe level (SLL) and half power beamwidth (HPBW). The particle swarm optimization (PSO) approach is employed in this O-QPAA structure to identify the optimal values of the three main QPAA parameters, which are inter-element spacing within each SAA or RAA, vertical spacing, and the non-uniform excitations of the LAA to form the entire O-QPAA radiation pattern.