A novel printed monopole antenna with folded-line SIR loading

A novel printed monopole antenna with simple, low-profile and convenient design is presented in this paper. The antenna composes of a printed monopole antenna and a folded-line stepped impedance resonator (SIR) loaded on the bottom of the substrate. The resonant frequency is decreased by the coupling between the folded-line SIR as the near-field resonant parasitic (NFRP) element and radiation patch of the monopole antenna. The stronger the coupling, the lower the frequency. At the same time, the introduction of the NFRP element does not require an additional circuit for impedance matching, a novel the printed monopole antenna can be achieved. After analyzing the principle of the proposed antenna, a sample antenna has been manufactured and measured to prove the estimated performance of the proposed antenna. The measured results of the proposed antenna are consistent with the simulation, which shows that the design method in this paper is accurate and effective.