Controllable antenna with a radiation-pattern diversity reflector for DTV applications

This work presents a controllable antenna with a radiation-pattern diversity reflector for applications of Digital TV (DTV) terrestrial broadcasting systems. The design of the monopole antenna using a CPW-fed mechanism is adopted for achieving wideband characteristics. By properly choosing the feed line and the gap, the monopole antenna can have impedance matching in the whole UHF band. Furthermore, in order to enhance the receiving performance and control the radiation direction, three monopole antennas form a triangular array antenna. Particularly, the distance between the angle and edge of this triangular array antenna is adequately determined to yield good impedance matching. Additionally, which edge of the proposed triangular array antenna having the best receiving performance is acquired by sequentially switching on three monopole antennas. Experimental results demonstrate that the proposed triangular array antenna can operate at a frequency band from 470 MHz to 860 MHz in which the return loss is below -10 dB. The measured radiation patterns show the property of diversity where their beam directions can be effectively controlled to track the source location. Particularly, the proposed antenna has a gain ranging from 2.60 to 4.03 dBi. The experimental results reveal that the proposed antenna exhibits good characteristics suitable for various DTV applications.