Millimeter-wave multilayered design of rectangular metal waveguide-based slotted antenna

This work uses multiple layers of mechanically machined metal contours to assemble a K
a
-band (26.5GHz to 40 GHz) WR28 standard rectangular metal waveguide-based slotted antenna. The mechanical compression-based electronic packaging degrades the simulated electromagnetic results by tolerable margins. A total of 16 slots along the length of the waveguide is designed to obtain a maximum measured gain of 14 dBi along the broadside direction. To combat the inherent feature of low impedance matching bandwidth of such antennas, a shunt stub-based matching technique is implemented. The measured input reflection coefficient is better than -10 dB over 5 % bandwidth at a center frequency around 31.4 GHz with an estimated efficiency of 85 %. Apart from conduction loss, other losses are due to leakage from potential air gaps and surface roughness between the assembled layers of brass.