Embodiments of the invention are directed to retrodirective radio-frequency systems wherein a transmit antenna array includes at least one row of N transmit elements and a receive antenna array includes at least one row of N receive elements that correspond one-to-one to the transmit elements and wherein the transmit and receive elements are located on spaced planes, and centered about a common axis and located at common transmit distance and a common receive distance, respectively. In some embodiments the one row of transmit and receive elements comprises “n” rows of elements, where “n” is an integer greater than one, thereby forming a two-dimensional array. In some embodiments the total transmit radiation pattern provides an azimuth coverage of 360 degrees. In other embodiments, it may provide less coverage but be operable as independent sectors. In some embodiments, the desired transmit wave form will be identical between all transmit elements of the array, one possible example being pseudo random noise imparted on a sinusoidal carrier.