Abstract: The vehicular antenna generally suffers from the narrow operating band and large profile. To solve this problem, a low-profile wideband antenna is designed to install in the shark-fin housing of the vehicle. To realize the proposed wideband antenna, the resonant modes of a PCB monopole is fully exploited. By properly designing the antenna size, the resonant frequencies of this monopole are drifted to the operating band. Then the slots are deliberately designed and loaded on the monopole. Thus, more resonant modes are generated, and the antenna matching performance is improved to increase the bandwidth. Eventually, a compact antenna size is obtained. For demonstration, the proposed antenna is installed into the shark-fin housing for measurement. As exhibited by the measurement results, the operating band (824-5 000 MHz) can be covered by the proposed antenna. The antenna VSWR is less than 3, the minimum gain is 1. 9 dBi and the maximum gain is 6. 2 dBi, and the efficiency is from 49. 5% to 89. 2%. This indicates that, the proposed antenna can satisfy the wideband and compactness requirement of the vehicle communication.