An inset-fed dual-frequency circular microstrip antenna with a rectangular slot for application in wireless communication

An inset-microstrip line-fed circular microstrip antenna with a rectangular slot on the radiation element for the dual-frequency operation is proposed. The circular microstrip antenna resonates at 1.58 GHz and 2.43 GHz, which enables it´s usage in the wireless communication domain such as in Wireless Local Area Network (WLAN). The two excited modes, which are responsible for the dual-band operation for the proposed antenna, are the TM₁₁ and TM₀₁. TM₁₁ is the fundamental as well as the dominant mode for this proposed antenna. The two modes have the similar broadside radiation characteristics and same polarization planes. By varying the lengths of the rectangular slot, the proposed antenna can provide a tunable frequency ratio of 1.50 to 1.62 for the two operating frequency bands.