In this paper, we present the simulation and experimental validation of an ultra-thin planar metamaterial absorber, which is composed of Jerusalem crosses loaded by interdigital capacitors. By increasing the coupling capacitance between adjacent unit cells, we are able to significantly lower the operating frequency of the absorber. The measured results indicate that the metamaterial absorber achieves a peak absorption of 88.48% at 1.58 GHz. The total thickness and the unit cell size of the absorber are 2 mm and 11 mm, which are approximately 1/95 and 1/17 of the working wavelength, respectively. Additionally, the Jerusalem crosses and the metallic ground plane are connected by vias, which makes the metamaterial absorber achieve wide-angle absorption for both transverse electric and transverse magnetic polarizations electromagnetic wave. The absorptivity is still large even at the incident angle of 60°, and the frequency of the absorption peak almost has no deviation, which makes the absorber more practical.