Monopole-like antenna for GSM, UMTS, and WLAN applications

The microstrip planar monopole-like antenna, MPM, capable of multiband operation is proposed. The MPM antenna constructed as microstrip 50-Omega line loaded by the two planar resonant strips. The strips and the microstripline are photo-etched on microwave laminate Rogers TMM4. The inner loaded strips resonating as a quarter-wavelength structure and the outer folded strip resonating as both a quarter-wavelength and a half-wavelength structure. The flat (similar to 0.002 A) MPM antenna, 12 mm (<0.1 lambda) in height and 30 mm in width has been constructed, and the obtained bandwidths cover the four bands of three digital communication systems, centered: at 900 MHz and at 1800 MHz for the GSM, at 1900 MHz for PCS, and at 2050 MHz for UNITS, respectively. Results of design, simulations, and experiments are presented. (C) 2007 Wiley Periodicals, Inc.