A 16 × 16 substrate-integrated waveguide (SIW) cavity-backed array antenna is proposed in this paper. The array consists of two layers. The top layer employs novel SIW-based subarrays with a compact size. The bottom layer is an 8 × 8 SIW corporate-feed network to feed the subarrays. The Chebyshev amplitude weighting is employed in the feed network, which substantially reduces the side lobe level (SLL). The array antenna is fabricated using low-cost printed circuit board technology. The experimental results show that the proposed array antenna has a large bandwidth of 15% from 18.5 to 21.5 GHz with a peak gain of 29.1 dBi at 20.5 GHz. Across the entire band, high radiation efficiency above 62% and a low SLL below -17 dB are realized. The design principle can be used as a guidance for largescale planar array antenna design and the proposed antenna can be used as a receiving antenna located on the ground in satellite communication systems.