A Half-Mode Groove Gap Waveguide for Single-Layer Antennas in the Millimeter-Wave Band

This letter presents an alternative to significantly reduce the time and difficulty in designing and fabricating antennas in gap waveguide (GW) technology by using a novel half-mode groove GW. GW is often criticized within the subtractive manufacturing field for the high fabrication time required to mill many pins with the waveguides in the same piece. To demonstrate the possibilities of this new approach, two different antennas have been designed, fabricated, and measured. Both antennas, formed by only two pieces with no contact, operate from 29 to 31 GHz and present reflection coefficients below <inline-formula><tex-math notation="LaTeX">$-$</tex-math></inline-formula>10 dB and high antenna efficiency above 90<inline-formula><tex-math notation="LaTeX">$\%$</tex-math></inline-formula>. In addition, both prototypes can reuse the bed of nails, which favors shorter manufacturing times and lower costs in the development phase.