Folded Triple-Frequency Quasi-Yagi-Type Antenna with Modified CPW-to-Cps Transition

A novel side-feed quasi-Yagi type antenna capable of triple-frequency operation at about 1900, 2400 and 3600 MHz is presented in this paper. The antenna is composed of a folded quasi-Yagi element and a modified CPW-to-CPS transition. The proposed antenna can be mounted perpendicularly to the feed circuit board of an array antenna so that it offers a novel design with a free degree of feed point so as to save device space, and its folded quasi-Yagi element can result in a low profile to the system. The experimental results demonstrate that the proposed antenna can operate over three frequency bands, with -10 dB reflection coefficient bandwidths of 200 MHz, 200 MHz, and 400 MHz at the central frequencies of 1.9, 2.4, and 3.6 GHz, respectively. Moreover, in the whole working bands, the antenna basically keeps the same radiation pattern and the gain is over 2.6 dBi.