As automobiles evolve into individual wireless-communications networks, antenna makers have faced the task of providing ever-smaller antennas that handle more bands. Among the choices serving this market from placement on the roof or trunk are monopole, helix, and printed antennas. Mounted in a rear or side mirror, dashboard, or glove compartment, however, cellular antennas are less at risk to external agents. Unfortunately, such placement also puts them closer to electronic components that may impact antenna performance. At Italy’s Politecnico di Torino, two multiband-antenna designs that seek to overcome such issues have been designed by Sergio Arianos, Gianluca Dassano, Francesca Vipiana, and Mario Orefice.
The two antennas cover four frequency bands: GSM, E-GSM, DCS, and PCS. They are specifically designed to be integrated in a printed-circuit board (PCB), placed inside a plastic box, and mounted under the vehicle dashboard. The first version is a planar printed antenna. It is fully integrated into the PCB, minimizing cost. The second design—a three-dimensional antenna—requires no dedicated space on the PCB, as it is an independent part of the whole device.
Though slightly more expensive, this latter antenna does boast better performance. Yet both antennas show satisfactory performance in the required frequency bands. Because they have been created with the presence of other electronic components in mind, the antennas should not be affected by the presence of those components on the PCB. See “Design of Multi-Frequency Compact Antennas for Automotive Communications,” IEEE Transactions On Antennas And Propagation, Dec. 2012, p. 5604.