Circularly-polarized linear antenna array of non-identical radiating patch elements for WiFi/WLAN applications

Here we present a novel linear circularly polarized (CP) antenna array using non-identical CP elements, where the Chinese character-shaped patches are employed to form a linear array. Namely, the single-feed CP Zhong-, Guo-, and Meng-shaped patch antennas have collected to form a three-element antenna array. A one-to-three power splitter with equal amplitudes but unequal phase-shifts at its output ports was deliberated as the feed network for the linear array. The challenge of this antenna array design is the appropriate phase excitation to the non-identical radiating elements so that the CP gain and operating bandwidth can meet the requirements of the application(s), in which we undertook an in-depth investigation. A proof-of-concept design example for 2.4 GHz wireless local area network (WLAN, IEEE 802.11b/g/n) has demonstrated the effectiveness of the combination technique on the non-identical CP antenna elements. The simulation, in combination with experimental validation, obtained an on-axis 3-dB axial-ratio bandwidth from 2.28 to 2.59 GHz (12.7%), whereas a broadside gain of 9 dBic at 2.5 GHz and an overall efficiency of 82% were recorded within the bandwidth.