SSPP-Based mmWave Array Antenna Design Based on MSAO Framework

This paper presents the use of a Multi-Surrogate-Assisted Optimization (MSAO) framework to design and optimize two spoof surface plasmon polariton (SSPP) transmission line (TL) fed mmWave array antennas. The framework is aimed at simultaneously optimizing multiple design objectives such as S-parameters, gain, pattern, main lobe direction (MLD), and side lobe level (SLL). The SSPP transmission line fed array antenna has a complex design space with more than 30 variables, including the size and position of the circular patch. The first SSPP-TL-fed array antenna among the two fabricated antennas is capable of SLL less than -21.5 dB for both 27 and 28 GHz. The second antenna is designed to reduce the SLL in a given direction while maintaining the main lobe direction. The measurement results show the MLD at -2°, with the null at 35°.