Electrically Small rectangular microstrip patch antenna loaded with metamaterial

This paper presents a new electrically small rectangular microstrip patch antenna loaded with metamaterial multiple split ring resonator (MSRR). The unloaded rectangular microstrip patch antenna resonates at 14.80 GHz, after loading it by MSRR its resonant frequency is lowered to 6.15 GHz with the impedance bandwidth of 217 MHz. This antenna has gain of 5 dBi in a small size with the directivity of 7.60 dBi. In loaded condition, according to Chu limit the size of proposed antenna comes to ka = 0.944 which satisfies the condition for electrically small antenna that is ka <;1. The estimated radiation Q-factor (Q_rad) is 28.14 which is much larger than the Q_chu minimum that is Q_chu=2.269.