Signal-to-Noise Ratio Enhancement of High Frequency Ground Wave Radar Based on a Metamaterial-Based Transition Structure

A metamaterial-based transition structure is proposed in this paper for converting the power from a radar antenna installed on a costal sand land to the surface wave supported by the air/sea interface instead of leaky wave into the air or sky. With the proposed structure, the power from the antenna can firstly couple to the spoof surface plasmon polariton (SPP) mode sustained by the metamaterial-based transition structure. After propagating away from the costal line, the SPP guided-wave mode then couples to the conventional surface wave propagating along the air/sea interface by mode-matching technique. Simulated results reveal that the signal-to-noise ratio (SNR) of HF ground wave radar can thus be enhanced over 8 dB in a wide frequency range by adding the proposed metamaterial-based structure in front of the radar antenna installed on the sand land. The design concept can also be applied to the HF ground wave radar to reduce the sky wave interference due to reflection from the ionosphere.