Hi all! Currently designing an antenna to perform dual band frequencies of 890 - 960 MHz and 1710 MHz - 1880 MHz. However regardless of the changes I've made, the best I've gotten for s11 is only the first frequency band. The second frequency band is nowhere near my requirement.
The top side of the substrate is the balun feeding the 3 dipoles at the bottom side. dielectric constant at 4.4, thickness at 0.8mm. width of balun is 1.5mm.
this is the s11 result I got.
Hope to receive some advice on my design, it will help alot! thanks.
Modified planar quasi-Yagi antenna for wlan dual-band operations
Chang, Dau-Chyrh (Dept. of Electrical Engineering, Da-Yeh University, Datsuen-Shiang, Chang-Hua, Taiwan); Chang, Cheng-Bing; Liu, Ji-Chyun Source: Microwave and Optical Technology Letters, v 46, n 5, p 443-446, September 5, 2005
Right now, I have gotten the results but my prof had requested a smaller size of the antenna. Any suggestions? I've increased the permitivity of the substrate to 10.2, but it didn't reduce much. Gonna try meandering now.