Millimeter‐Wave High‐Gain LTCC‐Integrated Endfire Antenna Array Based on Compact Multi‐Slot Excitation of High‐Order Mode

ABSTRACT This letter presents a compact multi‐slot excitation scheme of high‐order mode in substrate‐integrated waveguide (SIW), which is employed to feed the low‐temperature cofired ceramic (LTCC) endfire antenna array with a high‐gain performance in millimeter‐wave (MMW) band. A dielectric‐loaded tapered slot antenna (TSA) is designed as the antenna element for high‐gain endfire radiation. The linear array of TSA elements is fed by a high‐order mode SIW acting as a multiway feeding network. Due to the removal of electric wall between adjacent fundamental mode, the high‐order mode SIW leads to a relaxed LTCC fabrication of MMW integrated antenna array. In this design, the TE 80 mode is directly generated based on a compact multi‐slot excitation without an additional power distribution network, and an 8‐element dielectric‐loaded TSA array is fed by the TE 80 ‐mode SIW. The proposed LTCC prototype is analyzed and fabricated, obtaining a good agreement between simulation and measurement. The measured impedance bandwidth of 14% (31.3–36 GHz) is achieved under |S 11 | < −10 dB, and the peak gain is 13.1 dBi within the working band. Compact structure, directive endfire radiation, and relaxed fabrication make the proposed endfire antenna array great potential in MMW LTCC‐integrated systems.