An ultra wideband antenna with proximity-coupled multiple shallow cavities for uniform gain

Using a novel concept of proximity coupled multiple shallow cavities an ultra wideband antenna with uniform gain is designed. Its operating bandwidth is from 4 GHz to 12 GHz. A parametric analysis and design guidelines, highlighting the gain enhancement over a broad range of frequency, is presented. A significant improvement of 2 to 3 dB gain over the whole frequency range is demonstrated. This antenna has a theoretical gain of 6.24 dBi and a very small maximum gain variation of 1.17 dB over a bandwidth of 8 GHz.