A Low‐Profile Dual‐Polarized Unidirectional Antenna Based on the Dipole With High Input Impedance

In this paper, a dual‐polarized unidirectional antenna with extremely low profile is developed. The radiator of the antenna is a square patch with two stepped slots etched in the lower left corner and the upper right corner. A port is set at the end of the stepped slot, thereby stimulating the radiator to produce two vertically polarized waves. In addition, a square slot is set in the upper left corner of the square patch to adjust the current flow from the excited port into the non‐excited port. Due to the special design mentioned above, an additional current peak appears on the edge of the radiator when either port is excited, which increases the input impedance of the antenna. In this way, the problem of decreasing input impedance caused by decreasing antenna height is solved. The transverse size of the proposed antenna is roughly the same as that of the ordinary dual‐polarized base station antenna, whereas the height is reduced by 81%. In conclusion, the low‐profile dual‐polarized antenna proposed in this paper can be used in the base station system and has a good application prospect.