Ku-band Low-profile Wide-angle Scanning Microstrip Circularly Polarized Phased Array Antenna

This paper proposes and simulates a broadband, wide-beam microstrip circularly polarized antenna, which is then used to form a 8×8 phased array. Bandwidth expansion in the microstrip antenna is realized by introducing slots on the upper ground layer and implementing a microstrip line-coupled feed configuration. Parasitic rectangular loop patches are utilized to broaden the bandwidth and the beam-width of the antenna element. A metallic cavity penetrating through three layers of dielectric board is used to broaden the beam-width of the element by the longitudinal currents generated on its surface. Simulation results show that the antenna element operates in the frequency range of 12.3-13.3 GHz. At the frequency of 13 GHz, its beam-width can reach approximately 110°. The overall size of the antenna is quite small, only 8.5 mm × 8.5 mm × 2.92 mm, with a profile height of 2.92 mm, exhibiting a low-profile characteristic. The 8×8 phased array composed of these elements can maintain a gain reduction within 3dB and an axial ratio within 4.5dB within a 50° scanning range.