Design of a Notch Filter Element to Mitigate WiMAX EMI of an UWB Antenna

This paper presents the design and analysis of a notch filter element to mitigate WiMAX electromagnetic interference (EMI) of an ultra-wideband (UWB) antenna. The designed WiMAX band-notched antenna is modeled on an FR-4 substrate (ε<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</inf> = 4.3, tan03B4; = 0.02) having a physical dimension of 26×28×0.8 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>. A very simple T-shaped slot is incorporated into the patch plane as a notch filter element to mitigate the WiMAX interference in the frequency range of 3.38 GHz to 3.83 GHz effectively. The antenna has a minimum return loss value of -28.03 dB. The maximum gain and directivity values of 3.17 dBi and 3.9 dBi are obtained respectively at 6.05 GHz. It exhibits an average radiation efficiency beyond 80% for the entire operating band (3 GHz to 10.79 GHz) excluding the WiMAX interfering band. The maximum value of the efficiency is 91.76% recorded at 3.1 GHz. The suggested design features a low profile, simple notching technique, and satisfactory performance making it a suitable candidate for future WiMAX EMI free UWB applications.