A Broadband Low-Profile High-Gain Low-Sidelobe Directional Planar Antenna

This paper describes a low profile, broadband, high gain and low sidelobe directional planar antenna. To realize the low profile, the printed circuit board (PCB) technology is adopted in the design process of the directional antenna, such as broadband microstrip antenna unit and feed network. To achieve the low sidelobe, array feed network integrated design is used in the design process of the directional antenna. To reduce the manual assembly steps and errors, multi-layer PCB processing is applied to ensure the precision of the unequal feeding amplitude among the antenna units. An antenna prototype is fabricated and exemplified to validate the proposed concept. Measured results show that the designed antenna achieves an impedance bandwidth of 26. 1%. Further, a measured maximum boresight gain up to 23. 6 dBi is obtained. The sidelobe levels of E-plane and H-plane are smaller than -27. 4 dB and -28. 3 dB, respectively. The front-to-back ratio is smaller than -42. 2 dB within the bandwidth range.