Improving bandwidth and return loss of Si-based MEMS antenna using suspending and electromagnetic band-gap structures

A novel Si-based MEMS antenna with topside suspending and backside electromagnetic band-gap (EBG) structures is developed in this study to improve its high-frequency performances. The proposed Si-based micromachined antenna with dimensions of only 7 mm × 22 mm × 0.5 mm is constructed of a 0.2 μm-thick copper ground plane, six 10 μm-thick copper supporting vias, a 6 μm-thick suspending F-shape copper conducting layer and 3 × 9 arrayed silicon cavities (to form the backside EBG structure). Using the Taguchi method and commercial Ansoft-HFSS simulation software, the dimension of EBG structure is optimized (1.66 mm × 1.66 mm × 0.35 mm) for development of a Si-based MEMS antenna with low loss and broadband. The implemented Si-based antenna demonstrates very low return loss (−35.5 dB, at 4.85 GHz) and wide fractional bandwidth (FBW = 43%, at 3.75–5.8 GHz), which approximately matches with the simulated results (return loss = −41.6 dB and FBW = 36%) at 5.15 GHz.