A Low-Profile Monopole-Like Small Antenna with Embedded Metamaterial Spiral-Based Matching Network

A low-profile, monopole-like, electrically small antenna is reported in this paper. The major radiating elements of the proposed antenna are two low-profile posts that are located close to each other and above a common ground plane. These posts are connected though a spiral-based, fully printed, metamaterial matching network that sets the phase of the flowing currents so that the radiated fields of the two closely located posts do not cancel each other in the far field. The resulting electrically small antenna radiates vertically polarized fields over a fractional bandwidth of 1 %, exhibiting a relatively high radiation resistance.