Antenna Impedance Tuning Unit for DVB-H Front-End

When implementing wide band low frequency antennas in small devices, e.g., mobile phones using DVB-H, a large mismatch is inevitable. An impedance tuning unit (ITU) can then be introduced to reduce the reflection losses and noise and improve the gain. An ITU consisting of 6 switched capacitances and 2 fixed LTCC inductors is investigated. Both simulations and measurements show that the ITU reduces a V SWR = 10 mismatch to better than V SWR = 2. Furthermore, simulations show that it increases the power delivered by 2.9 dB to 4.2 dB for an antenna mismatch between V SWR = 4 and V SWR = 8. At the same time, the average noise figure for V SWR = 4 is reduced by 1.4 dB from 4.6 dB to 3.2 dB; and for V SWR = 8 it is reduced by 2.8 dB from 6.4 dB to 3.7 dB. The highest noise figure for V SWR = 8 is reduced by 4.2 dB from 9.1 dB to 4.9 dB.