Millimeter-Wave Waveguide Slot-Array Antenna Covered by a Dielectric Slab and Arrayed Patches

A high-performance waveguide, 16 times 16 slot array antenna with a cover structure at 38 GHz is presented. The protective cover structure, which consists of a dielectric slab and arrayed conductor patches, offers an advantage for designing a highly directive array antenna because it lowers the resonant conductance of the slot set such that a large number of slots can be arrayed. The widths of the slots in this antenna are fixed to 1 mm for easy production with a common computer-controlled milling machine. Moreover, the manufacturing process for this antenna is simplified by positioning the waveguide corrugations and slots together on a plate, which eliminates a welding process. Measurements show an antenna gain of 30.8 dBi, a depolarization level below -30 dB, and an efficiency level of 71% at the frequency band of 37.638.6 GHz.