Wideband, Low-Profile Slot-Fed Dipole-Patch Antenna and Array

A wideband, low-profile dipole-patch antenna element consisting of a printed dipole and four tightly coupled microstrip patches is proposed. The element, housed in a substrate-integrated-waveguide (SIW) cavity, is slot-fed by two vias residing on the opposite sides of a dumbbell-shaped aperture. The simulated results reveal that it operates from 22.3 to 32.1 GHz for standing-wave ratio (SWR) ≤ 2 with a peak gain of 9.6 dBi, low cross-polarization level less than -25 dB, and stable radiation patterns across the operating band. The element thickness is only 0.071λ
₀
, where λ
₀
is free-space wavelength at the center frequency of 27.2 GHz. An SIW-fed 8 × 8 antenna array with nonuniform power distribution is then designed, fabricated, and measured to verify the properties of the element. The measured E- and H-plane radiation patterns are stable across the operating band with sidelobe and cross-polarization levels below -17 and -22 dB, respectively.