Cavity-Backed Angled-Dipole Antennas for Millimeter-Wave Wireless Applications

Abstract

A cavity-backed angled-dipole antenna is proposed for millimeter-wave wireless applications. The angled-dipole radiator is built on both sides of an RT/Duroid 5880 substrate (εr=2.2) and fed by a parallel-plate transmission line. The cavity-backed reflector is utilized to improve the radiation characteristics of the angled dipole, such as gain, back-radiation, symmetric pattern, and similar 3 dB beamwidth in theE- andH-planes. The design, with a cavity aperture of0.5λ28-GHz×0.5λ28-GHz, results in aS11<-10 dB bandwidth of 26.7–30.6 GHz, a gain of 6.6–8.0 dB, and a similar 3 dB beamwidth of approximately 70° for both theE- andH-planes. Eight-element linear arrays with the proposed antenna having a center-to-center spacing of 5.6 mm(0.52λ28-GHz)are characterized, fabricated, and measured. By applying nonuniform power distribution across excitations, the array achieves a scan angle up to 40° and a sidelobe level below −15 dB.