A broadband circularly polarized monopole antenna for millimeter-wave short range 5G wireless communication

This article describe the design and measurement of a broadband circularly polarized (CP) monopole antenna for millimeter wave short range 5G Wireless communication applications. This antenna is comprised of a T-shaped monopole antenna with an inverted-L grounded stub and an asymmetric coplanar wave guide feed. To attain the broadband CP, an inverted-L grounded stub is embedded in the coplanar ground and introducing asymmetry in the horizontal T-shaped patch connected feed line monopole antenna. A compact size of 1.877λ_L × 1.706λ_L × 0.130λ_L is accomplished when measured at lower edge frequency (f_L,|S11|). For the proposed antenna structure conforming to f_L,|S11|, a measured 3-dB axial ratio bandwidth of 13.67% (4 GHz, 27.26-31.26 GHz), impedance bandwidth of 27.9% (8.3 GHz, 25.6-33.9 GHz), peak gain of 7.15dBi, and a bidirectional patterns with a dual sense polarization are attained.