A Wideband Aperture-Shared Dual-Polarized End-Fire Antenna with Low Profile and High Isolation

This paper proposes a new wideband aperture-shared dual-polarized end-fire antenna for millimeter-wave (mmWave) applications. Firstly, a reshaped quasi-PIFA element with L-probe feeding is adopted to produce end-fire single vertical polarization (VP) radiation. A pair of dual-layer patches are then loaded in front of the quasi-PIFA element, which serves as both resonator and director towards simultaneous impedance bandwidth and gain improvement. U-slot is further introduced to the quasi-PIFA element to broaden the impedance bandwidth. This results in a low profile, wideband, and high gain VP end-fire element. Secondly, based on the single VP end-fire antenna element, by using the two VP elements' dual-layer patches as the two arms of a dipole with horizontal polarization (HP), a dual-polarized element can be realized. The dual-layer patches function as both the resonator/director of VP and the radiator of HP, leading to a compact dual-polarized design with good performance. Prototypes of the proposed antenna are designed and fabricated by low-temperature co-fired ceramics (LTCC) process technology with 12 dielectric layers (0.11 lambda(0)). moreover, the differential signal and common signal in dual-polarized feeding are naturally isolated.