Skip to Main Content
A small-size microstrip-fed multi-band planar monopole antenna is presented. The base of the proposed antenna is a diamond-shaped-patch (DSP) that covers the ultrawideband (UWB) frequency range. To create a multi-band antenna, several narrow strips, acting as resonance paths, can be integrated with the DSP antenna. It is shown that by removing the centre part of the DSP antenna, without distorting the UWB behavior, quarter-wavelength strips can be added to the notched region. This will not affect the dimension of the base antenna. The designed quad-band antenna has a substrate size of 16 × 22 mm2 and covers the frequency bands 1.3, 1.8, 2.4 and 3.1-10.6 GHz which includes GPS, GSM, WLAN and UWB. Dual-, triple- and quad-band antennas are simulated and good results are obtained. The antennas have omnidirectional and stable radiation patterns across all the relevant bands. Moreover, relatively consistent group delays across the UWB frequencies are noticed for the base, dual- and triple-band antennas, and slightly distorted for the quad-band antenna. A prototype of the quad-band antenna is fabricated and measured results are compared with simulated results.