A very small dipole (very short compared to the wavelength) is equivalent to a capacitance. C_eq is equal to the half length of the dipole divided by epsilon_0 and by the logarithm of the ratio length - diameter. But, in an array of such very small dipoles (all the sames), coupling effects will change this capacitance value. I suppose the equivalent capacitance of one dipole is put in parallel with other capacitances, whose values depend on the x and y periods of the array. Where can I find such formulas?