A Wideband High-Gain Cavity-Backed Low-Profile Dipole Antenna

In this communication, a compact, wideband, low-profile, and high gain dipole antenna is proposed. A microstrip coupling line is used to feed the ellipse pairs, which is two arms of the antenna. This simple feeding structure can significantly enhance the impedance bandwidth (IBW). A cavity-backed structure is adopted to achieve the low-profile antenna. With the influence of the cavity-backed structure, the new antenna has a higher gain over the whole frequency band. An optimized antenna with a height of only 0.17λ (where λ is the free space wavelength at the lowest frequency) is designed and measured. The measured result shows that the IBW for VSWR <; 2 is 117% (2.48-9.51 GHz). Further, the gain bandwidth (Gain > 6 dBi) from 2.57 to 8.73 GHz is more than 108.9%. The antenna radiation pattern performs well over the whole band, and the peak gain can reach 11.8 dBi.