covers the required bandwidth . Figure 3 studies the effects of the strip length L 2 of the C-shaped strip on the impedance matching of the proposed antenna. Measured results of the return loss for the case with various strip lengths of L 2 ϭ 5 to 7 mm are presented. It is seen that, by increasing the strip length L2, the antenna's lower band can be excited at lower frequencies. For the upper band, however, smaller effects of the strip length L 2 are seen. From the results obtained, the strip length L 2 for the printed meander antenna is selected to be 7 mm.The radiation patterns in the orthogonal x-y, y-z planes at 2.45, 5.25, and 5.8 GHz are shown in Figure 4, respectively. The measured results show good similar omnidirectional radiation in the azimuth plane (x-y plane), especially in the higher band, and conical radiation in the elevation plane (y-z plane). Figure 5 presents the measured peak gains of the proposed compact monopole antenna across two operating bands. The measured peak antenna gains for the operating frequencies across 2.4/5-GHz bands are measured to be 2.7 and 3.1 dBi, respectively. Gain variations of 2.2-2.7 dBi in the 2.4-GHz band and 2.0 -3.0 dBi in 5-GHz band are obtained.
CONCLUSIONA novel multiband printed monopole antenna for WLAN communication has been proposed. By using a simple configuration, the prototype of the antenna has achieved satisfactory multiband performances, which obtains impedance bandwidths of 2.39 -2.52 and 5.12-7.12 GHz, the measured gains of 2.0 and 3.1 dBi, respectively. Also good similar omnidirectional radiation patterns in the azimuth plane in higher band are achieved. It is of low cost, light weight, and has a compact size of only 11.5 ϫ 8.5 mm 2 . These features are very suitable for multiband wireless applications.
ABSTRACT: This article presents the design and fabrication of a short-pin dual-band E-shaped microstrip patch antenna for applicationin a 2.630 -2.655 GHz band satellite-DMB with a 5.725-5.825 GHz band wireless LAN. The prototype consist of a short-pin and E-shaped patch. To obtain sufficient bandwidth in VSWR Ͻ 2, an air layer is inserted between the ground plane and the substrate. A small short-pin patch that has a dual-band characteristic is used. Important design parameters are the slot's existence, length, the air-gap's height, the feed point's position, and the short-pin's existence and point position. From these optimized parameters, an E-shaped antenna is fabricated and measured. The measured results of the fabricated antenna are obtained individually at 200 and 700 MHz bandwidths in VSWR Ͻ 2 referenced to the center frequency, and the individual gain at 8.79 and 10.26 dBi. The experimental 3 dB beam width is shown to be broad across the passFigure 5 Measured antenna gains for the proposed antenna: (a) 2.4-GHz band; (b) 5-GHz band. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com]