Switched dual mode patch antennas for mobile systems

Many new satellite based services are planned for road vehicles including telephone and data communications, vehicle positioning systems and traffic information. Compact antennas are required to receive all these services. These must be cheap to manufacture, as conformal as possible with the vehicle, offer multiple frequency band operation and a variety of radiation patterns to operate with both geostationary and continuously orbiting satellites. Here the properties of annular ring microstrip patch antennas operating at higher order modes are assessed for use on vehicles in mobile communication systems. The antennas have been studied both theoretically and experimentally to examine the radiated beam shape, gain and the bandwidth for several methods of feeding. The performance of rings printed on different substrates and a glass superstrate are examined