A W-Band Circular Polarized Antenna for Print Circuits Board Phased Array Applications

This paper presents a circular polarized antenna working at the W-band for a single Print Circuits Board (PCB) phased array. By adding proper shell structures, the whole antenna array is capable of $+/-10^{\circ}$ beam scan range without generating significant grating lobes. The simulated S11 of the proposed antenna is less than -10 dB from 94 GHz to 97 GHz, and the side lobe of a $4 \times 4$ array is less than 10 dB at all scan angles. The total phased array with the proposed antenna was fabricated and tested. The measured pattern results show 6.76 dB side lobe at $94 \mathrm{GHz}, 6.57 \mathrm{~dB}$ at 96 GHz, and 6.65 dB at 98 GHz, respectively.