Compact Microstrip Antenna With Enhanced Bandwidth by Loading Magneto-Electro-Dielectric Planar Waveguided Metamaterials

A new concept of planar magneto-electro-dielectric waveguided metamaterials (MED-WG-MTM) is proposed to manipulate the effective permeability μ_eff and the effective permittivity ε_eff. The MEDWG-MTM cell consists of an electric complementary spiral ring resonator (CSR) in the upper metallic plane and a magnetic embedded Hilbert-line (EHL) in the ground plane. The characterizations and working mechanisms are investigated in depth through eletromagnetic (EM) simulation, circuit model calculation and effective material parameters analysis. Numerical results show that the MED-WG-MTM can be manipulated with a larger refractive index for miniaturization and a larger wave impedance for bandwidth (BW) enhancement. For demonstration and potential applications, a microstrip patch antenna working at 3.5 GHz and occupying an area of only 0.20λ₀ × 0.20λ₀ is designed by using the derived flexible three-step frequency tuning method. A good agreement of results between the simulations and measurements suggests that the designed antenna advances in many aspects such as compact dimensions with a 42.53% miniaturization, broad operation band with a 207% impedance BW enhancement, and comparable radiation performances relative to its conventional counterparts.