LAUSR

In this letter, we examine underwater wireless communications using electromagnetic waves in marine shallow waters. Due to the particular environment under study (low frequencies, short distances, and small loop antennas), a magnetoquasi-static approach is used instead of full-wave analysis. The electric field generated by a constant current circular loop placed on the interface between two conductors is analytically calculated. Using this electric field, the mutual coupling coefficient between the two loops is calculated, and a simple circuit model for transmitting energy from one loop to another is presented using a transformerlike element. Simulations using the circuit model and a commercial full-wave simulator are carried out, and their results are compared. Very good agreement is observed between both results.