Single-feed square-ring patch antenna with dual-frequency operation

The paper presents the design of a dual-frequency patch antenna with different radiation patterns. The antenna structure is composed of a square-ring patch and two shorting walls. Two resonant modes, patch-loaded monopole mode and normal patch mode, can be simultaneously excited in the antenna structure by a coupling strip inide the square-ring patch. Therefore, the antenna can radiate monopole-like and broadside patterns at two operating frequencies, respectively. Several prototypes of the proposed dual-frequency patch antenna with the frequency ratios ranging from 1.18 to 1.73 are constructed, and the obtained experimental results are also shown. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 991–994, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22308