I am looking for antennas for vehicule traking. In fact, the antennes will be stuck with magnetic under the vehicule. For GPS antenna (patch), there is no problem, i think, as it has his own ground plane but for GSM900 antenna, there is a problem. Indeed, to preserve a good S11, the reflector should be at lambda/4 and it is equal approximatly 80 mm and i didnt have this height. So i tought to use a printed antenna with a ground plane, but i didnt found that in the litterature, can anyone guide me where to found or perhaps advice me another solution.
thanck you in advance