A dual-port antenna for GPS and UWB operations

A dual-port antenna is proposed to operate in the two frequency bands of global positioning system (GPS) and ultrawideband (UWB). First, the shorted ring-slot antenna is etched on the top surface of the FR4 substrate to radiate circularly polarized (CP) waves in the GPS band. Second, a monopole antenna, which is responsible for operation in UWB, is constructed on the bottom surface. In order to reduce the coupling coefficient, the monopole antenna is located in the center region of the bottom surface and the microstip line is placed in the specific region, whose reverse side is grounded. The measured data for impedance and axial ratio (AR) bandwidths in the GPS band are 320 MHz (21.1%) and 80 MHz (5.0%), respectively. As for UWB, experimental results show that the reflection coefficient is below - 10 dB between 2.93 GHz and 10.7 GHz. The antenna gain in GPS is 4.74 dBic and those in UWB are between 4.4 and 5.8 dBi. Moreover, the measured coupling coefficient is below -14 dB between 1.5 GHz and 10 GHz, which implies that the proposed antenna can operate independently in the bands of GPS and UWB.