Miniaturized printed monopole antenna with applying the modified conductor-backed plane and three embedded strips based on CPW for multi-band telecommunication devices

Abstract

In this article, a new construction of a small planar dual-band fed printed monopole antenna based on coplanar waveguide is suggested. Impedance matching for dual-band operations is obtained by embedding three vertical strips with different sizes in the U-shaped conductor-backed plane. The main problem of the designed antenna is the measuring of the specifications with the Agilent 8722ES Vector Network Analyzer, when the coaxial cable is connected to the antenna. Hence, in this paper a new method for decoupling the cable from the antenna is presented. This method is based on using the ferrite bead. The ferrite bead reduces the cable radiation, so that its position plays the important part in the antenna radiation characteristics. The fabricated antenna includes the benefits of the miniaturized size and dual-band operating specifications, so that the mentioned properties have been achieved without modifying the coplanar-waveguide-ground surface or radiator patch. The antenna has the small size of 15 × 15 × 0.8 mm3and bandwidths with S11 < −10 dB about 2.2 GHz (5.05–7.25 GHz) for WLAN-band or IEEE 802.11a-band and 5.2GHz (7.6–12.8 GHz) for X-band, which correspond to 36 and 51% practical bandwidths, respectively. The antenna measured peak gains are about 1.8 dBi at WLAN-band and 4.3 dBi at X-band.