Broadband high‐gain low‐temperature cofired ceramic substrate integrated cavity antenna array based on high‐order mode for W‐band applications

A broadband substrate integrated cavity (SIC) antenna array based on high‐order mode is proposed for low‐temperature cofired ceramic (LTCC) integrated systems in W‐band. To improve the gain of antenna element, a large SIC is adopted to work in high‐order mode, which also avoid using excessive vias and reduce the process complexity. Two parasitic patches are loaded on the high‐order mode SIC to remove the reverse E‐field in the open aperture, leading to a high‐gain broadside radiation. The high‐order‐mode SIC antenna element is fed by high‐order TE 20 ‐mode substrate integrated waveguide (SIW), rather than regular TE 10 ‐mode SIW. The simplified feeding network with TE 20 ‐mode SIW is also designed with wideband performance, further enhancing the fabrication robustness of antenna array. To validate the proposed high‐order mode‐based antenna element and feeding network, a W‐band 2 × 4 antenna array is designed as an example using LTCC technology. The measured return loss is better than 10 dB from 81.1 to 98.1 GHz (19% bandwidth) with a maximum gain of 18.3 dB at 94 GHz. The proposed antenna array has great potential in millimetre‐wave and terahertz LTCC integrated applications.