The Profile Reduction of an Electronically-steerable Parasitic Array Radiator Based on Inductance Loaded Quarter Wavelength Dipole

Small-size and low-profile of the antenna play a key role in wireless mobile communication equipment. This paper designs a small-size and low-profile quarter-wave electronically-steerable parasitic array radiator (ESPAR) monopole antenna working in the WLAN band. The antenna is miniaturized by series inductors on the antenna, and capacitors are loaded on top of the antenna to adjust the impedance matching of the antenna. The simulation results show that the length of the proposed ESPR antenna is reduced to 16.7 mm, which is 46.6% lower than the length of the traditional quarter-wavelength monopole antenna. It is clear that this way can successfully reduce the size of ESPR antenna while ensuring a good impendence matching.