Compact satellite navigation antenna array using off-the-shelf ceramic patch antennas

We aim at developing a miniaturized four-element satellite navigation receiver to achieve robustness, precision and accuracy in challenging environments, suitable for economical industry-scale fabrication and assembly. In this paper, we present a four-element compact antenna array for the public L1/E1-bands, i.e., 1575.42±2 MHz, based on commercially available ceramic antenna elements. It is observed that due to the compactness of the antenna array the mutual coupling degrades the radiation properties, particularly the axial ratio. We propose a modification in the ground-plane to reduce the axial ratio below 3 dB in the main-lobe directions, which is necessary for the navigation receivers. Moreover, to mitigate the mutual coupling, a decoupling and matching network using off-the-shelf directional couplers is incorporated.