A Novel Dual-Band Printed Monopole Antenna With Modified SIR Loading

In this paper, a novel dual-band compact printed monopole antenna is presented. The antenna is composed of three spatially distributed layers: a modified folded-line stepped impedance resonator (SIR) on the upper layer, a printed monopole antenna on the middle layer, and another folded-line SIR on the lower layer. A pair of resonant frequencies can be introduced by loading two different modified folded-line SIRs as near-field resonant parasitic elements (NFRPs) in the near field of a printed monopole antenna. Simultaneously, the resonant frequencies of the two are lower than the fundamental mode frequency of a traditional printed monopole antenna, thereby enabling the realization of a compact antenna. Furthermore, the resonant frequency can be adjusted through the wide edge strong coupling between the folded-line SIR and the printed monopole antenna. After elaborating on the design principles, a sample antenna is fabricated and underwent measurements to validate the anticipated performance of the proposed antenna. The measured outcomes closely align with the predicted results, providing compelling evidence that the design methodology expounded in this paper is indeed precise and efficacious.