Miniaturizing the axial mode helical antenna

The helical antenna can be made significantly smaller with little sacrifice in its most desirable properties. We propose here a method for reducing the size of helical antennas, and demonstrate its efficacy on a fairly typical antenna with a low number of turns (N = 6). After investigating several methods, we demonstrate that by introducing a periodic sinusoidal pattern along the helix and reducing the radius, height and pitch, the volume of the antenna can be reduced by more than 6 times. A surprising effect, pitch desensitization, which aids in miniaturization is also demonstrated and studied. Further, it is demonstrated that the dependence of some antenna characteristics on pitch can be replaced by a dependence on patterning parameters, allowing for more design space when choosing the geometric dimensions of the antenna.