A Broadband and High-Gain Planar Complementary Yagi Array Antenna With Circular Polarization

A novel planar end-fire circularly polarized (CP) complementary Yagi array antenna is proposed. The antenna has a compact and complementary structure, and exhibits excellent properties (low prolile, single feed, broadband, high gain, and CP radiation). It is based on a compact combination of a pair of complementary Yagi arrays with a common driven element. In the complementary structure, the vertical polarization is contributed by a microstrip patch Yagi array, while the horizontal polarization is yielded by a strip dipole Yagi array. With the combination of the two orthogonally polarized Yagi arrays, a CP antenna with high gain and wide bandwidth is obtained. With a prolile of 0.05λ
₀
(3 mm), the antenna has a gain of about 8 dBic, an impedance bandwidth (|S
₁₁
| <; -10 dB) of 13.09% (4.57-5.21 GHz) and a 3-dB axial-ratio bandwidth of 10.51% (4.69-5.21 GHz).