A compact inexpensive UWB-modified elliptic antenna including a slotted ground plane for an indoor positioning system

Within the present article, an original inexpensive UWB-modified elliptic antenna including slots in its ground plane is presented. This antenna with the FR4-epoxy substrate has a very modest size of 21 × 24 × 1.6mm3. The measured results confirm that the suggested antenna has an impedance bandwidth (|S11|< − 10 dB) of 134.13%, which expands from 3.1 to 15.72 GHz, covering the entire UWB frequency range and reaching a maximum gain of approximately 9.5 dBi at 14 GHz with an average value equal to 3.3 dBi throughout the functional frequency band and a maximum radiation efficiency of 97% obtained for the frequency 8.3 GHz with an average value equal to 94% over the whole frequency band. Excellent accordance between the simulation and measurement is observed. This antenna presents an approximately omni-directional radiation diagram in some directions, a dipole-like radiation pattern at lower frequencies and a quasi-stable group delay through the operating band, making the antenna relevant for most useful UWB applications, especially for indoor localization. Impedance matching is performed by employing two ellipses with diverse semi-major axes ″a″ as radiating patches and by optimizing the size, number, and position of the inserted slots in the downsized ground plane. Detailed information on the simulation and experimental results is provided and discussed.