When a dielectric meta-atom is placed into a subwavelength metallic aperture, 20-fold enhanced electromagnetic transmission through the aperture is realized at the meta-atom’s resonant frequency. Additionally, when the incident electromagnetic power increases, thermal energy gathered by the meta-atom, which is converted from electromagnetic losses, can cause the meta-atom’s temperature to increase. Because of the high temperature coefficient of the meta-atom’s resonant frequency, this temperature increase causes a blueshift in the transmission peak. Therefore, this frequency-dependent enhanced electromagnetic transmission even produces a nonlinear effect at low incident powers. Over an incident power range from 0 to 20 dBm, measured and simulated spectra near the meta-atom’s resonant frequency show distinctly nonlinear transmission.