Loss reduction & bandwidth enhancement by air-region insertion to LTCC rectangular-waveguide slot arrays in the millimeter-wave band

This paper introduces a LTCC single-mode waveguide of ε
_r
=6.6 and tanδ=0.013 inserting air region in the half along the height to reduce the transmission loss and the effective dielectric constant. The transmission loss of the waveguide has been reduced to 1/6. The total gain is enhanced by 8dB and the 3dB bandwidth is also been increased from 1.3GHz to 2.3GHz in a 12-element slot array antenna in the 60GHz band.