Generally, increasing the electrical size of an antenna will increase the directivity of the antenna. In the case of an array of identical antennas with uniform spacing, the electrical size can be increased by increasing the number of elements. However, directivity can be further increased by performing signal processing on the signals received by elements of an antenna array. This thesis focuses primarily on reproducing and expanding upon a method to increase the directivity of a two-element array using non-linear transmission lines periodically loaded with varactor diodes, which act as harmonic multipliers. Simulation and circuit design is performed using Keysight Advanced Design System, a microwave circuit simulation software package. Furthermore, a hardware implementation is discussed and recommendations are made for construction of the hardware array. Finally, possible expansion of the two-element array to a four or more element array is discussed, and preliminary simulations are examined.