In this letter, a broadband substrate integrated waveguide (SIW) cavity-backed triangular-ring-slotted antenna is demonstrated for planar integration. Instead, using a conventional triangular-ring-slot, a modified triangular-ring-slot is employed to achieve a broader bandwidth response. The conventional triangular-ring-slot generates two hybrid-modes in the vicinity of TE110 and TE120 cavity modes owing to strong loading effect in the SIW cavity resonator. The modified-slot helps to tune the individual resonant frequency of these hybrid modes below −10 dB, which leads broadband impedance bandwidth. The antenna is fabricated and tested, and the experimental results show a bandwidth of 2.09 GHz (13.53%) and a gain of 4 dBi over the entire bandwidth. Moreover, antenna exhibits unidirectional radiation characteristics with uniform gain. © 2018 Elsevier GmbH