A compact, wideband array of coupled quarter-wavelength slot antennas for the 700 MHz band

In the United States, the UHF television broadcast switched from analog to digital in 2009. The spectrum efficiency of the digital broadcast has freed up about 108 MHz of bandwidth that is considered for wireless communication. This band is located between 698MHz to 806 MHz part of the spectrum and referred to as the 700 MHz band. Out of this spectrum, 70 MHz is allocated for commercial use, 34 MHz for public safety, and 4 MHz for guard band. It is expected that all mobile devices be capable of operating over the entire 700 MHz band. For this purpose, small antennas that can be incorporated into handheld devices are of interest. This poses a challenge to design small antennas that can provide the required bandwidth. It is also highly desirable to design such antennas to be compatible with PCB fabrication technology for cost requirements.