5G Millimeter Wave Endfire Array Antenna with Printed Inverted-F Structure

In this design, a novel inverted F antenna with a low profile feed structure is proposed for millimeter-wave (mmW) applications. The array element consists of a printed inverted F antenna and a L-shaped parasitic deflector, approximately forming a structure similar to the Yagi-Uda antenna. The gain could be increased and the impedance bandwidth could be broadened by the structure. And, it is important to realize the miniaturization of the antenna element by bending the parasitic deflector based on the traditional deflector without affecting the performance. The proposed antenna has a low feed substrate height (0.254 mm∼0.02λ0), which makes it easy to integrate with planar circuits. As proof, a 1 × 4 array model with an impedance bandwidth of 20.5% (23.0–28.3 GHz) is designed and measured. The inverted F array demonstrated is an important candidate for mmW applications due to its wide bandwidth, miniaturization, ease of integration with planar circuits, and low manufacturing cost.