Microstrip antenna array for mobile communications

Several challenges remain however in the development of antenna array for mobile communications and one of these is the availability of efficient radiating elements interfacing with the beamformer. This paper presents therefore a development effort for a novel printed array antenna. In this paper we presents a modification version of such antennas by adding a series capacitance to the patch equivalent circuit, implemented by electromagnetic coupling and varying the distance between the successive elements in a non linear way. It was found through experiments that the bandwidth of such antennas is increased to 1.5 GHz. The comparaison of the theoretical results montionned above and the measured values showed a good agreement. The design and realization of this log-periodic arrays at 30 GHz, are implemented on a high dielectric constant substrate (epsilon(tau) = 9.9), which is close to the dielectric constant of GaAs. The feasibility of integration of such an antenna strucuture into a monolithic circuits is demonstrated