Low Frequency Gain Improvement of a Vivaldi Antenna Without Compromising with Its Overall Size and Higher Frequency Gain

A Vivaldi antenna with improved gain at lower frequency is presented for 4 - 18 GHz band applications. Gain at the lower frequencies is improved by introducing a linearly tapered corrugations along the outer edges of a traditional Vivaldi antenna. A maximum of 2.5 dB gain improvement is obtained at 4.0 GHz for a balun integrated antenna. This modification does not degrade the high frequency performance of the antenna. The low-frequency gain can be further improved at the cost of lower gain at higher frequencies. A parametric study is presented to understand the effects of the modified geometry on various antenna parameters. Finally, design steps are presented for other frequency band or other substrate materials.