Multi-band modified fork-shaped microstrip monopole antenna with ground plane including dual-triangle portion

A modified fork-shaped microstrip monopole antenna with the ground plane including a dual-triangle portion is studied experimentally to obtain a large bandwidth and a multi-band characteristic. In this case, the ground plane including a dual-triangle portion leads to improving the impedance matching for a lower band. Although the use of a high relative permittivity (/spl epsiv//sub r/=4.3) substrate usually restricts the operation bandwidth, the radiation resistance also was a low value. The 2.0 VSWR impedance bandwidth is 29.8% (731-987 MHz) for a lower band, and 90.2% (1498-3080 MHz) for a higher band operation. This single-layer microstrip monopole antenna also retains a low and a thin profile characteristic.