Wideband Ka-band printed dipole array antenna with parasitic trapezoidal patch

This work presents a printed Ka-band dipole array antenna with wide bandwidth for millimeter-wave communication applications. The operating band of the proposed antenna ranges from 27.8-38.2 GHz exhibiting a wide bandwidth of 10.4 GHz. A balun structure is designed with interlaced U-shaped bending lines on the upper and lower metal layers to feed the dipole differentially. Parasitic trapezoidal patches are exquisitely placed adjacent to the driven dipoles for coupling, which can enhance bandwidth significantly through multiple resonances. The low-frequency radiation is mainly contributed by the resonance of the dipole, while the high-frequency radiation is affected by both the dipole and the parasitic trapezoidal patch. Due to the trapezoidal patch, the equivalent path length of the resonant current becomes shorter, thus supporting high-frequency resonance. A prototype of the proposed 1 x 2 dipole array antenna was fabricated for validation. The measured -10-dB impedance bandwidth is up to 27.8 similar to 38.2 GHz (or 31.5%) and the realized gain is as high as 8 dBi, which is suitable for advanced millimeter-wave communication applications.