A Self-Decoupling Wide-Angle Scanning Pattern Reconfigurable Antenna Array Using Parasitic Comb Structures

A self-decoupling wide-angle scanning pattern reconfigurable antenna array (PRAA) is proposed in this article. The problem of active element pattern deviation caused by coupling in PRAA has been solved, thereby improving the PRAA's ability for wide-angle scanning. The pattern reconfigurable antenna (PRA) in the PRAA is composed of a driving dipole antenna with parasitic elements integrated with p-i-n diodes. The comb structures (CSs) are used as parasitic elements of the PRA to achieve self-decoupling in the PRAA. The working mechanism of the CSs is investigated by characteristic mode analysis (CMA) theory. The results indicate that CSs can reduce the coupling between adjacent parasitic elements as well as the coupling between PRAs in the PRAA. Compared to the PRAA composed of traditional parasitic rectangular structures, the proposed PRAA exhibits a maximum reduction of approximately 17.3 dB in sidelobes and a maximum increase of approximately 2.5 dB in gain during beam scanning. A proposed 1 x 4 PRAA is fabricated and measured. The results confirm that the proposed PRAA can achieve scanning from -60(degrees )to 60(degrees), with gain fluctuations less than 2 dB and sidelobes lower than -7.31 dB. Additionally, the proposed PRAA eliminates the degradation of cross-polarization caused by increasing scanning angles. Within the +/- 60(degrees) scanning range, the cross-polarization remains below -28 dB. When the beam scans within +/- 40(degrees), the cross-polarization performance is optimal, reaching approximately -36.23 dB.