Microstrip Planar Monopole-Like Antenna for Mobile Handsets

The microstrip planar monopole-like antenna, MPM, capable of multiband operation is proposed. The MPM antenna constructed as microstrip 50-Omega line loaded by two the 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 (~0.002 lambda) 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 UMTS, respectively. Results of design, simulations, and experiments are presented.