Modeling the performance of electrically-large antennas is vital to many Department of Defense applications. However, this can be very computationally-demanding because of the enormous CPU time and memory required for high-fidelity analysis. For example, the finite-element discretization of large-scale electromagnetic problems, such as large finite antenna arrays, often results in a system of linear equations involving millions or even billions of unknowns. Their solution is very challenging, even with the most powerful high performance computers available today. A new parallel algorithm called Electromagnetic Finite Element Tearing and Interconnecting Method (FETI-EM) has been developed in the past few years to address the above challenges. In this paper, we describe the FETI-EM algorithm in some detail, and the work in progress to benchmark and develop this algorithm into a library of code routines that can be integrated into the CREATE-RF SENTRI code.