Frequency invariant interferometry

The authors discuss frequency-independent phase comparison interferometry as a method of direction finding. Theoretical relationships are derived that show the electrical phase between two elements of an array can remain approximately constant over frequency. The theory is developed for log-periodic dipole arrays. Design and fabrication of a two-element interferometer using log-periodic antennas are discussed. Experimental results are presented which show that this array remains frequency independent over a three-octave bandwidth