LTCC Oversized Rectangular Waveguide Slot Array Antenna With Air-Layer in the Radiating Part in the Millimeter-Wave Band

This paper presents an LTCC oversized rectangular waveguide slot array antenna with an air layer in the radiating part. The antenna is fed by an LTCC fully-filled waveguide. The air-layer addition reduces the transmission loss to enhance the gain. It also reduces the effective dielectric constant to enhance the bandwidth of the series-fed slot array. The measured near-field distribution shows the hard-surface sidewalls to enhance the field uniformity on the aperture by ensuring quasi-TEM mode propagation. The transmission loss in the radiating part with the addition of the air layer of half the height was reduced compared with conventional fully-filled LTCC antenna.