NOVEL TWO-LAYER MILLIMETER-WAVE SLOT ARRAY ANTENNAS BASED ON SUBSTRATE INTEGRATED WAVEGUIDES

A novel slot array antenna with two layers of substrate integrated waveguides (SIW) is presented for millimeter-wave wireless applications. Unlike conventional SIW-based slot arrays, in this structure a feed waveguide is placed underneath the main substrate layer containing the slot array and is coupled to the branches of the array via slanted slots. The proposed feeding structure results in a considerable reduction in size and eliminates unwanted radiations from the feed network. Experimental results for two slot arrays with 4×4 and 6×6 elements operating at 60 GHz are presented showing 14.8 dB and 18.5 dB gain, respectively. Furthermore, a novel doubly tapered transition between SIW and microstrip line is presented which is particularly useful in mm-wave applications.