A circularly polarized printed elliptical wide-slot antenna with high bandwidth-dimension-ratio for wireless applications

Abstract

This paper outlines a simple design of a compact wideband microstrip-line fed antenna having two rotated elliptical wide-slots (EWSs). Here, both the elliptical wide-slots are placed perpendicular to each other which shows the measured 10 dB return loss bandwidth (RLBW) of about 7.78 GHz (4.94–12.72 GHz; 88.11%). The circular polarization (CP) is achieved by varying either the semi-major axis of any of the elliptical wide-slot or angle between the EWSs. The proposed antenna radiates left-handed circularly polarized (LHCP) and shows the measured axial ratio bandwidth (ARBW) of about 2.05 GHz (5.4–7.45 GHz; 31.91%) which falls completely inside the operating frequency band and hence relevant for wireless applications including an upper-frequency band of WLAN, WiMAX and several standards of IEEE 802.11 including a/h/j/n/ac/ax. The proposed antenna also achieves a high bandwidth dimension ratio (BDR) of about 1062 which along with the ARBW is the highest among the recently reported antenna structures. A peak gain of about 4.39 dBi is reported within the entire operating band while the overall size of the antenna is only $$18\,\times \,17\,{\text {mm}}^2$$ (or $$0.29\lambda _o \times 0.28\lambda _o$$ ; where $$\lambda _o$$ is the wavelength corresponding to the lowest operating frequency, i.e., 4.94 GHz). The performance of the proposed antenna in terms of RLBW, ARBW, gain, and efficiency are validated experimentally which are in concordance with the simulated results.