Development of electrically small planar antennas with transmission line based impedance matching circuit for a 2.4 GHz band

We designed an electrically small antenna (ESA) with the impedance matching circuit on the thin patterned circuit board. Matching circuit is realized by using interdigital gap and transmission line which is composed of coplanar waveguide (CPW). By using our new impedance matching circuit, we can reduce the total antenna size much smaller than one-wavelength. Moreover, we design some ESAs with impedance matching circuit, which have various gains, and discuss about the relations between peak realized gains and S-parameters. Also, we fabricated and measured the ESAs, and compared experimental results of S-parameters and simulated gains.