A Wideband Planar Dipole Antenna Array Fed by SICL for Millimeter Wave Applications

A wideband substrate integrated coaxial line (SICL)-fed planar dipole antenna array is investigated for millimeter wave applications. Different from the traditional dual-armed dipole antenna, a balanced symmetric structure is formed to improve the cross-polarization level by canceling the vertically polarized electric-field components. Meanwhile, three slots are etched on the dipole arms for two operating modes to broaden the operating bandwidth of the dipole element. By these methods, the dipole antenna achieves a cross-polarization level below −28 dB and an impedance bandwidth of more than 65%. To further improve the gain of the antenna, a $1\times 8$ dipole array is proposed. The measured results show that the proposed dipole array can achieve a wide −10 dB impedance bandwidth of more than 70.6% from 22.3 to 47 GHz, and cross-polarization levels below −20 dB. With the merits of wideband, low cross-polarization, low profile and easy integration, the proposed antenna array is valuable to millimeter wave communication.