A small quad-band automotive antenna

An electromagnetic bandgap (EBG) structure based quad-band antenna for automotive applications is designed, simulated and measured in this paper. The EBG acting as a high impedance surface (HIS) is a novel dual band structure, constructed on 1.6mm thick FR-4 (εr=4.4) board, with the reflection phase and surface wave bandgaps in the 2.7 GHz and 5.9 GHz ranges. The simulated reflection phase bandwidths are 4.5% and 5% for the first and the second band respectively. The measured surface wave bandgaps are 11% and 7.5% for the first and the second band respectively. The novel EBG has more band flexibility in comparison with the conventional double square patch EBG. A wideband printed circular disc monopole antenna uses this novel EBG as a HIS resulting in a low profile quad-band antenna system with a height of 6.2mm. The frequency bands covered are UMTS (1.925–2.175 GHz), WLAN (2.4–2.485 GHz and 5.15–5.825 GHz) and V2X (5.76–5.84 GHz) using a −10dB reflection coefficient criteria. It is demonstrated that the boresight gain increases by 0.6 to 8.6 dBi when the EBG is used as a ground plane for the antenna.