Design of inset-fed quad-band circular microstrip antenna for 2.4/5 GHz WLAN, WiMAX and X-band satellite applications

摘要

An inset-fed circular shaped microstrip patch antenna and pair of inverted T-shaped slits for wireless communications is presented. In its basic form, a microstrip patch antenna consists of a dielectric substrate with radiating patch on one side and a ground plane on the other side. There are several advantages of this type of antennas such as planar, low cost, low profile, easy to fabricate, simple in structure with small in size, thus attractive for practical applications. The dimensions of proposed circular microstrip antennas which is fed by simple 50Ω inset-fed of length L_f=17.18 mm and W_f= 3.17 mm and radius R= 11.5 mm on the top surface of the FR4 substrate with thickness t=1.6 mm and bottom of the substrate a ground plane of size W=55.4 mm, L=44 mm is used. To obtain a quad-band operation, a pair of inverted T-shaped slits are inserted at the edges of the circular radiating patch with lengths of T_(11)=15 mm and T_(12)=4.4 mm. The proposed antenna is resonating for four particular frequency points at 2.33 GHz, 4.18 GHz, 5.04 GHz and 6.49 GHz with impedance bandwidths of 2.7%, 2%, 2.1% and 2.6%. The antenna shows a broadside radiation characteristic at desired frequency bands and covers the WLAN (2.4-2.48/4.97-5.12 GHz), X-band lower satellite communication (6.42-6.59 GHz) applications.