Wide band flat antenna for mobile microwave terminals

The article relates to lens antenna of reduced thickness and formed of a inhomogeneous dielectric. It can be readily incorporated into microwave broadcast and communication systems, including portable satellite telephone and broadcast stations, and very attractive as a wide bandwidth antenna at 10-80 GHz. This lens antenna can be used in microwave quasi-optical active arrays when active elements are located on a flat dielectric surface with high thermal conductivity. Lens antennas could be utilized as receiving and transmitting antennas in many applications, but being formed of a homogeneous dielectric they have many practical disadvantages including high weight, complex surface form and thickness that have limited their implementation. The problem of complex surface form can be addressed by forming the antenna lens from a flat piece of inhomogeneous dielectric material. While such lenses have certain unique features that cannot be achieved with lenses formed of a uniform dielectric, they do not solve the problem of weight and thickness associated with lens antennas. Lens antennas have some common and attractive advantages over reflector antennas. Lens antenna production needs less precision. Besides the phase mistakes are maximum in the center of reflector antennas and near the border of lens antennas. Consequently, their influence is much smaller for lens antennas. Lens antennas are extremely broadband and scan a beam inside a wider angle sector than is usual for reflector antennas