An electronically scanned antenna array for TACAN bearing finding applications

This paper describes a unique method for obtaining the sinusoidal amplitude modulation of an RF carrier required for TACAN (tactical air navigation) bearing and direction finding applications using an electronically scanned antenna array. This is accomplished by using one central radiating element and six surrounding radiators. The phase of the RF current in the central radiator is varied linearly at the desired rotation frequency, while the phase of the currents in the surrounding elements is held constant (with respect to each other). This is unique in that it does not require a variable phase shift for all elements (only the central one).<>