Four-element compact planar antenna array for robust satellite navigation systems

In this paper, we present a four-element compact planar antenna array for global navigation satellite systems. The array is designed for the 1575.42 MHz (L1 band) frequency having an inter-element separation of d = λ/4. In order to compensate mutual coupling and mismatching, a specifically designed decoupling and matching network has been integrated into the array. We investigate the resulting antenna performance, such as axial-ratio bandwidth, and realized gain, as referred to the decoupling and matching network input ports. Furthermore, we present a receiver model to characterize the equivalent spatial carrier-to-interference plus noise ratio of the antenna array, decoupling and matching network, and low-noise amplifier, using a conventional null-constraint beamformer.