電磁最佳化實驗室EM Optimization LabYen-Sheng Research Group, Department of Electronic Engineering

A novel pixelated ultra-Wideband (UWB) antenna for wireless body area network applications (WBAN) is proposed. The proposed antenna is constructed by the pixelated design technique, which discretizes the design space into several pixels and searches for the optimized structure by means of Strength Pareto Evolutionary Algorithm 2 (SPEA2). The proposed antenna has four design goals: miniaturization, wide impedance bandwidth, uniform broadside gains, and high time-domain fidelity factors. While the miniaturization is achieved by a new discretization method called brick design, the other three performance criteria are attained by the multi-objective capability of SPEA2. As a result, the proposed antenna, fabricated on a 1.6-mm-thick FR4 substrate, has a small size of 15 × 15 mm2; meanwhile, the return losses are larger than 10 dB throughout the interested frequency band, and the variation of the broadside gain is reduced from 10.23 dB to 2.39 dB. In addition, the group delay is decreased from 0.94 ns to 0.40 ns, and the fidelity factor is enhanced from 0.87 to 0.92. Moreover, the proposed antenna is tested in several WBAN environments. The measured frequency-domain and time-domain results show that the proposed pixelated antenna is very suitable for WBAN applications.