Probe-fed multi-band microstrip single-patch antennas

The property of multi-band operation has been studied and investigated analytically through the design of a number of rectangular patch microstrip antennas. Two techniques for introducing multi-band operation are adopted in this paper. They are: the probe-fed square patch antenna with three shorting pins at one of the patch´s radiating edges, and the probe-fed rectangular patch antenna with different numbers of wide slots arranged at both of the radiating edges. It is shown with the first technique, the patch can resonate at three different frequencies of 1.83 GHz, 2.16 GHz and 2.74 GHz with adequate radiation characteristics to meet the requirements of wireless communication systems. It is also shown that with the second technique, a patch with three slots has a multi-band feature with four resonant frequencies at 1.6 GHz, 1.8 GHz, 2.65 GHz, and 4.83 GHz and adequate values of return loss and gain.