The tunable application for mobile handset antenna

The design trend of mobile handset become slim and thin, and the handset has covered a lot of communication service bands including GPS, WiFi, and Bluetooth. Moreover, 4G communication service needs plural antennas and the handset has been supporting additional functions such as cameras, sensors, and u-USB. Because of these backgrounds, the antenna design condition is becoming worse and this causes poor radiation performance. Based on the limited antenna volume, controlling the antenna impedance by tuner is one of the good solutions for designing the antenna. Tuner can modify the impedance characteristics of antenna and it makes possible to have multiband in the low frequency range under 1 GHz. Even though there are very shrunk antenna volumes inside the phone, we can overcome the bandwidth problem in low band partly. Recently, the handset should support the CA service in LTE bands, this is becoming a big challenge for antenna designers.