The design of the antenna starts from a loop antenna shown in Fig. 2 without the
short-bars, in which a meandering is applied for the miniaturization purpose and
a comb-like feeding for the effective excitation at multiple frequencies. Figure 3
compares the calculated and measured input characteristics of the loop antenna
where the calculation is based on a Poynting-MWR
software. Figure 4 shows the
current distributions on the loop antenna at several frequencies and it is shown that
resonances occur at different places for different frequencies.