Conformal Multifunction Antenna for Automobiles

The development of a conformal automobile antenna having more than three functions began in 1993 at Wang Electro-Opto Corporation (WEO, formerly Wang-Tripp Corporation) [1-5]. It was an internally funded effort to develop a rooftop-mount multifunction antenna that can simultaneous handle six functions: AM and FM radios, remote keyless-entry, cell phone, satellite communications and satellite geolocation (GPS and GLONASS). The design was soon selected by a major U.S. automobile manufacturer for possible integration into a new passenger car model. Unfortunately, the prototype development effort funded by that auto manufacturer was short-lived. First, the RF performance requirements established for the analog world was overly, and unnecessarily, demanding. Second, the auto manufacturer’s “body people” were still in a denial mode against the cavity that must be cut out on the car to accommodate the antenna being designed. Indeed, the development effort was way ahead of both real market needs and technology maturity. Over the last fourteen years, rapid growth of wireless services has led to a proliferation of antennas on automobiles. As a result, there are now serious efforts to develop conformal multifunction automobile antennas to reduce the antenna counts on cars [e.g., 6-7]. This paper discusses some key design issues and the latest approaches at WEO.