Multi-feed NVIS realization on small aircraft using characteristic modes

Characteristic modes (CMs) are used to design an NVIS antenna system on-board an electrically small UAV. Using the CMs of the UAV platform, near-vertical incident skywave (NVIS) are realized using pre-specified locations for antenna mounting. The appropriate excitation level of each monopole feed can be computed in a systematic manner using the CMs of the composite UAV + monopole antenna system. Discussions on pattern and bandwidth of this approach as a function of feeding element number will be presented, as well as discussions on further optimization approaches that can be effectively utilized from a characteristic modes perspective.