Wideband internal dipole–loop antenna with switchable and tunable frequency operation for ultra-high-definition television

This study presents the implementation of an internal antenna for ultra-high-definition televisions (UHD TVs), which has encountered challenges such as inherently narrow impedance bandwidths, limited space, and the effect of material properties of the TV to the antenna performance. The proposed antenna consists of a pair of rectangular arms (the dipole mode), which are fed by the coaxial cable, these arms are also connected to the ground plane (the loop mode) through two shortings that excite an additional resonance mode. In addition, reconfigurable antennas also offer attractive potential solutions to solve the challenging antenna problems related to narrow bandwidth using the ability to switch and tune operation frequency. Herein, a frequency reconfigurable dipole–loop antenna which can cover the entire ultra-high-frequency band (UHF: 470–771 MHz, BW: 47.4%) is achieved using PIN diodes for switchable frequency and varactor diodes for tunable frequency. A 49-inch UHD TV is used for the practical implementation experiment. The TV bezel ( ԑ r  = 3.5, tan δ  = 0.005) is used as the substrate for the antenna design. The designed antenna for UHD TV applications achieves good impedance matching and stable radiation characteristics in the UHF band, considering S 11  = − 6 dB (VSWR 3:1) as the impedance matching criterion.