Wideband 60-GHz LTCC circularly polarized patch antenna with a U-slot

This paper presents a 60-GHz wideband circularly polarized (CP) U-slot patch antenna array of 4×4 elements on low temperature cofired ceramic (LTCC). A CP U-slot patch antenna is used as the array element to enhance the impedance bandwidth and a stripline sequential rotation feeding scheme is applied to achieve wide axial ratio (AR) bandwidth. The fabricated antenna array has a dimension of 14×16×1.1 mm³. Measured results show that the proposed antenna array has a wide impedance bandwidth from 50.5 GHz to 67 GHz for |S₁₁| <; -10 dB, and a wide AR bandwidth from 54 GHz to 65.5 GHz for AR <; 3 dB. In addition, it exhibits a peak gain of 16 dBi and a beam-shaped pattern with 3-dB beam width of 20^o.