Transmission Coefficient Measurements Using a 2.48-4.7 GHz Lateral Multiband Microstrip Patch Antenna (MB-MPA)

Abstract

We designed a standard triple-wavelength multiband microstrip patch antenna (MB-MPA) by electromagnetic simulation and fabricated it using an FR-4 substrate. The fundamental resonant frequency f₁ was 2.48 GHz, the second-order resonant frequency f₂ was 3.7 GHz, and the third-order resonant frequency f₃ was 4.7 GHz. The f₂ signal resonated at 1/2 the length of the patch width W, and the electrical field intensities of E_φ and E_θ showed π/2 rotation polarization relative to the f₁ signal. The polarization angle of the f₃ signal was about 34 degrees as the f₃ signal resonated at a length of 1/2 of the oblique line of the right triangle consisting of the shortened length L and 1/2 of the width W of the patch. The 0.1 - 6 GHz frequency band reflection and transmission coefficients of S-parameters S₁₁ and S₂₁ measured at a spatial propagation distance of 0.1 - 0.3 m with MB-MPAs as the transmitting and receiving antenna were consistent with the transmission system simulation results. The simulated transmission coefficient S₂₁ at three wavelengths with a spatial propagation distance of 10 - 50 m with two-stage LNAs showed practical values. The lateral resonant MB-MPA can be practically designed by using 3D electromagnetic current density distribution, electric field intensity radiation, and evaluating the transmission coefficient S21.