Frequency tunable antennas for mobile phone for terrestrial digital TV broadcasting reception

In this paper, two types of loop antenna and a broadband T-shaped antenna with a switch mounted on one end of its conductor are proposed. A RF switch such as single port multi throw (SPMT) is chosen rather than variable capacitors for these proposed antennas. Variable capacitors such as a diode, however, are influenced by the radiation power of cellular phones. Moreover, a bias voltage should be controlled continuously to change its resonance frequency. Tunable antennas can be designed as a built-in antenna with the full frequency coverage. Simulations and experiments are conducted to clarify its operation