A compact antipodal Vivaldi antenna (AVA) with the dimension of 42 × 36 × 1.6 mm3 is proposed in this letter. Structural modifications in the radiating fins have increased the electrical length thereby reducing the lower operating frequency from 5.2 GHz to 3.7 GHz. Proposed antenna maintains -20 dB copolarization to cross-polarization ratio throughout the operating bandwidth. The prototype is fabricated and the measurement results are presented to validate the performance of the proposed AVA. © 2002-2011 IEEE.