NOVEL MINIATURIZED BROADBAND QUASI-YAGI ANTENNAS BASED ON MODIFIED BOWTIES DRIVER FOR WIRELESS TECHNOLOGY APPLICATIONS

This paper presents two novel miniaturized broadband Quasi-Yagi antennas which adopt compact layouts and two different modified bowties as driven dipoles. In these antennas, the microstrip feed and λ/4 impedance transformer are placed horizontally and rearranged in a same horizontal line with balun to reduce the vertical size. The horizontal size is reduced by loading the vertical metallic strips at the sides of bowtie driven dipole and ground patch. Compared with the conventional QuasiYagi antenna, the sizes of the two proposed antennas are decreased to approximately 50%. The experiment results exhibit that they have wide bandwidths of 2.27–3.35 GHz and 2.14–3.3 GHz for reflection coefficient below −10 dB. Their gains reach 4 dBi over the operation frequency band, which indicate that they can be applied conveniently in wireless communications and recognition fields like WLAN, RFID, WiMAX and LTE frequency bands.