Fan-beam patch antenna array with low cross-polarization

This paper presents a fan-beam patch antenna array with low cross-polarization. The proposed antenna array consists of 13 sub-arrays and each array has 7 elements. The element distance in each array is equal, whereas the distances between the sub-arrays are designed to be different in order to decrease the radiation in the side lobe level. Narrower beam width and lower side lobe level can be realized by the proposed antenna array. The proposed array element is composed of a patch with a rectangular slot, a U-shaped reflection plate and a feeding network which is similar as a printed dipole. The size of single antenna element is only 0.45λ
0
× 0.25λ
0
× 0.08λ
0
, thus small windward area and low profile can be obtained by the proposed antenna array. For demonstration, a 13 × 7 antenna array operating at 566 MHz–606MHz is designed. The implemented antenna array achieves a cross-polarization of 40 dB, a horizontal beam width of 5°, a gain of 23.5 dBi and a sidelobe level of −20 dB.