High-Gain Series-Fed Planar Aperture Antenna Array

A high-gain series-fed planar aperture antenna array is proposed for 60 GHz applications in this letter. The array exhibits wide impedance bandwidth, low cross polarization, and symmetrical radiation patterns without beam squinting thanks to the differential feeding. Because of the large element size for the planar aperture antenna, the element spacing will cause high sidelobe level (SLL) if conventional array feeding scheme is adopted. Therefore, a new interleaved-series feeding approach is introduced, which enables the array to achieve a stable, high gain and low SLL simultaneously. Measured results show that the array has a wide bandwidth of more than 18.2% (55-66 GHz) with a peak gain reaching 20.4 dBi occurring at 59 GHz. The radiation patterns of the array are generally symmetrical with its beam fixed at boresight. The SLLs of the patterns are below -13 dB, and the cross polarizations are as low as -30 dB. These good features demonstrate that the array can be a good candidate for the 60 GHz communication systems.