Improved radiation characteristics of compact antipodal Vivaldi antenna with the hybrid technique for UWB applications

A compact antipodal Vivaldi antenna with stable end-fire radiation properties over the bandwidth of more than 15:1 is proposed for UWB applications. The gradient titled corrugated edges used to redistribute the antenna surface electric fields are employed to extend the low-end cutoff frequency and increase the low-frequency antenna boresight gain. The asymmetric parasitic patch composed of two triangular patches with different height is introduced to couple more energy from radiating arms of the antenna and thus enhancing mid- and high-frequency gain. The proposed antenna is designed and optimized in detail. To validate the proposed design, a prototype is fabricated and measured. The simulation results are in good agreement with the experimental data. Measurement results show that, the gain variation of the proposed antenna is in the range of 5.4-13.7 dBi over 2.88-40 GHz with the a compact dimension of 40 mmx73 mmx0.508 mm. The compact dimension of the antenna makes it a good candidate for UWB applications.