Huh, neat! Tips for adding a Yagi antenna to wifi routers and equipment.
It’s easy to make a small Yagi for a wireless router even if it lacks an antenna connector. The photo shows how I added two parasitic elements to the sleeve dipole of my Netgear WGR614.
With the AO 8.51 Antenna Optimizer I modeled a three-element Yagi at 2412, 2437, and 2462 MHz. These are center frequencies of the lowest, middle, and highest U.S. Wi-Fi channels. To model the sleeve dipole, I optimized the length of an isolated driven element for minimum SWR. Then I added the parasitics and optimized their lengths and positions for maximum forward gain, including mismatch loss for a 50Ω source impedance. All optimizations weighted the three frequencies equally. Finally, I rounded the dimensions. Below are calculated performance figures at the channel centers using 30 analysis segments per halfwave. Forward gain includes mismatch and conductor losses.