Multiband millimeter-wave patch antenna with parasitic element

The present paper introduces a novel design of a triple-band millimeter-wave printed antenna. The proposed antenna radiates at 28 and 43 GHz as its first-order and second-order resonances, respectively. Also, the antenna is designed to radiate efficiently in a third higher frequency band of about 2 GHz bandwidth (from 46 to 48 GHz). The design method depends on a composite-patch structure where the primary radiating element is a circular patch of modified geometry to radiate at 28 and 43 GHz. An arc-shaped parasitic printed element is capacitively-coupled to the primary patch so that it can efficiently radiate over the wideband (46-48 GHz). The primary patch is fed through a microstrip line with an inset feed for impedance matching over the desired frequency bands. The antenna structure and the feeding line are printed on a thin dielectric substrate of low loss to be suitable for millimeter-wave operation. The antenna has high radiation efficiency, excellent impedance matching, and satisfactory values of the antenna gain over the operational frequency bands. A prototype is fabricated and subjected to experimental assessment of the antenna performance including the return loss and radiation patterns. It is shown that the experimental measurements are in agreement with the simulation results over the three frequency bands.