A small tunable multiband antenna with parasitic elements for mobile applications

We propose a novel tunable multiband antenna with parasitic elements for mobile applications. The proposed antenna covers LTE/WWAN (703-960 MHz, 1447-1510MHz, 1710-2170 MHz, and 2496-2690 MHz) with a small size of 60 mm × 8 mm × 2.3 mm Our proposed antenna's configuration consists of two branched 1/4λ monopoles, a parasitic 1/4λ monopole, a parasitic 1/2λ dipole, a dielectric material (ε r = 5.4), and a tunable capacitor. This parasitic 1/2λ dipole technique is a particularly effective method that can increase the bands without reducing the efficiency of the other antenna elements. Also, it does not need a large ground plane compared with the monopole. Because the low band (703-960 MHz) is wideband, the tunable capacitor is used to change the resonance frequency and total efficiency at the low band. The simulated and measured results show a total efficiency more than -3dB in the operation frequencies. The proposed antenna will be a good candidate for mobile applications with the LTE/WWAN operation.