A Broadband Antenna Array With HDI Technology-Loaded Multilayer Parasitic Patches in W-Band

In this letter, a broadband high-gain array antenna loaded with parasitic patches is introduced. To achieve the wideband impedance matching, three parasitic patches stacked above the driven patch are proposed. The overall measurement of the proposed antenna is 4.6λ
₀
× 4.6λ
₀
× 0.092λ
₀
(λ
₀
is the free-space wavelength at 94 GHz). Butterfly-shaped gaps and compact 2 × 2 power splitters are utilized due to the low wavelength of the W-band. According to the measurement, the proposed antenna has a broad bandwidth, with |
S
₁₁
| < −10 dB of 26.59% from 85.2 GHz to 110 GHz. In the (87 to 103) GHz band, the gain of the 8 × 8 array antenna is more than 22.2 dBi, and its gain fluctuation is less than 1.8 dBi across the whole operational frequency range. The measured E- and H-planes radiation patterns are stable across the operating band, with sidelobe and cross-polarization levels below −25 dB and −30 dB, respectively.