A microstrip antenna including a first substrate, a ground plane disposed on a first side of the first substrate, a first conductive layer disposed on a second side of the first substrate, wherein the first conductive layer is configured to resonate at a first frequency, a second substrate disposed on the first conductive layer, a second conductive layer disposed on a side of the second substrate, wherein the second conductive layer is configured to resonate at a second frequency, a first feed portion extending through the first substrate, and configured to provide first excitation signals to the first conductive layer, a second feed portion extending through the second substrate, wherein the second feed portion is configured to provide second excitation signals to the second conductive layer, and a conductive strip disposed in the first conductive layer and electrically connecting the first feed portion and the second feed portion.