A substrate integrated waveguide slot antenna for 79-GHz applications

A substrate integrated waveguide (SIW) slot antenna for 79GHz applications is proposed in this paper. In order to get the high gain and lower losses, the antenna is designed as a sub-array composed with eight slots, which fabricated in the wide side plane of the SIW, and placed along the central axis with the equal interval of half waveguide wavelength. The slots can radiate the electromagnetic energy through the field disturbance caused by the plated-through hole (PTH) positioned beside the slots. The antenna is fed by the 50 û coaxial-fed structure located from the bottom of SIW. This bottom-fed method is different from the traditional microstrip feeding method, it has more convenience to extend the 2-dimensional phased array through multiple independent subarrays in the 79-GHz applications. The simulated results of the subarray indicate that the frequency band with |S11|<−10dB is from 78GHz to 80GHz, and the cross-polarization is lower than −50dB. An array model with 3×5 subarrays is also fabricated and simulated, it is found that the array radiation efficiency can be evaluated larger than 80%, and the patterns are also extremely well qualified. The performances confirm that the proposed SIW slot antenna is suitable for the millimeter-wave electronic systems with the requirement of array antenna.