In this paper, two asymmetric co-planar waveguide (ACPW) fed circularly polarized (CP) zeroth-order resonance (ZOR) antennas (Antenna I and II) are presented using a composite right and left-handed transmission line (CRLH-TL) approach. By adding a stub on the left side of the ACPW ground and adjusting its length, circularly polarization property has been achieved in Antenna I. The simulated 3 dB axial ratio bandwidth (ARBW) of Antenna I is 1750 MHz (3.50–5.25 GHz). Next, the left side ground plane of Antenna I is further defected by etching a quarter wavelength slit to introduce a notch band (Antenna II). Antenna II has an extended 10 dB return loss bandwidth of 2200 MHz (3.28–5.48 GHz) with a band notch from 4.18–4.65 GHz that isolates the WiMAX and 5.2 GHz WLAN bands. ARBWs of 1080 and 870 MHz are achieved in the first and second band of Antenna II. The overlapping 3 dB ARBW and 10 dB return loss bandwidths of Antenna II in these two bands are 770 and 830 MHz, respectively.
This article presents design and analysis of three wide band zeroth-order resonance antennas (antennas I, II, and III) using composite right and left-handed transmission line (CRLH-TL) approach. Coplanar waveguide technology, single layer via-less structures are used to have the design flexibility. The bandwidth characteristics are analyzed by using lumped parameters of CRLH-TL. By introducing a simple slot in the ground plane of antenna I both bandwidth enhancement and circularly polarization characteristics are achieved in antenna II. Another quarter wave L-shaped slot has been introduced in the ground plane of antenna II to introduce a notch band in the frequency response of antenna III. Achieved measured 10 dB return loss bandwidth of antenna I and antenna II are 960 (3.3-4.26 GHz) and 2890 MHz (2.77-5.66 GHz), respectively. Antenna III offers measured 10 dB return loss bandwidth of 3220 MHz (2.32-5.54 GHz) with a band notch from 2.39 to 2.99 GHz that isolates the 2.4 GHz WLAN and 3.5 GHz WiMAX band. Antenna II and antenna III have circular polarization property with measured axial ratio bandwidth of 440 MHz. The measured peak realized gain of antennas II and III is around 1.53-2.9 dBi. K E Y W O R D S CRLH-TL, circular polarization, metamaterial antenna, wide band
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