Electrical engineering

Physics

Microstrip

Optics

Slot antenna

Engineering

Antenna efficiency

Circular polarization

Patch antenna

Composite material

STRIPS

Microstrip antenna

Antenna (radio)

Materials science

Capacitive sensing

Axial ratio

Optoelectronics

IEEE Transactions on Antennas and Propagation

A miniaturized circularly polarized (CP) metasurface (MS) antenna using capacitive loading is investigated. First, one novel miniaturized MS unit cell is proposed. By introducing a pair of capacitiveloading strips inserted along the diagonal of a corner-truncated patch, 56% size reduction is achieved for this miniaturized unit cell. Accordingly, a compact CP MS antenna of a 4 × 4 array composed by the miniaturized unit cells is designed and fed by a slot structure. Compared with the conventional CP MS antenna without capacitive-loading strips, 63% overall size reduction can be achieved. Furthermore, the CP radiation mechanism of the CP MS antenna is revealed and explained clearly using the characteristic mode analysis (CMA). For demonstration, a prototype of the proposed CP antenna was fabricated and measured. The measured 3 dB axial ratio (AR) band is from 3.33 to 3.63 GHz, and the 10 dB impedance band is from 3.02 to 3.82 GHz, while 6.5 dBi gain is realized within the CP operating band.

Miniaturized Low-Profile Circularly Polarized Metasurface Antenna Using Capacitive Loading