A Wideband 8 × 8 Slot Array Antenna Using Gap Waveguide MLW Coaxial Line Technology for mmWave Applications

The letter presents a wideband 8 × 8-element slot antenna array operating in the E-band. The proposed design employs a low-loss coaxial waveguide transmission line filled with air implemented using multilayer waveguide technology by vertically stacking thin, unconnected metal plates to meet the typical radiation pattern and bandwidth requirements of a slot antenna array. To validate the concept, the simulation and measurement results of an 8 × 8 slot antenna array are presented. The proposed antenna array exhibits |<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${S}_{11}$</tex-math></inline-formula>| < −10 dB and a realized gain of around 26.4 dBi from 70.7 GHz to 82.4 GHz. The main advantages offered by the MLW coaxial line technology are low profile, low-loss, mass-production capability, and low cost at mmWave frequencies.