LOW GAIN ANTENNAS FOR LAND-MOBILE TERMINALS

Satellite reception antennas were developed for trucks and cars. They are made of quadrifilar helices wih dielectric core; the truck one (3 lambda/4) includes a balun inside the core and a small ground plane for beam shaping; the car one (lambda/2) is provided with a NACA profiled radome to optimize the induced drag. Truck antennas with gain greater than 5 dBi by means of switched beams are presented. A pyramidal array of circular microstrip patches and a planar arrangement of four patches in different modes and frequencies, and two other designs with patches are also treated.