Mutual Coupling Reduction between Very Closely Spaced Microstrip Antennas Using CPW Structure

An efficient H-plane mutual coupling reduction method is introduced for very closely placed dual-element microstrip antennas operating at 2.4GHz. A simple coplanar waveguide (CPW) structure is introduced in the ground, energy from one element is guided to another element, artificially generating new kind of mutual coupling current. By optimizing size of CPW structure to achieve purpose that new mutual coupling current cancel out with original existing mutual coupling. More than 36dB isolation (vertical bar S-21 vertical bar) is achieved with dual-element broadside array that distance is less than 0.024 lambda(0) (lambda(0) is free space wavelength).