Design and Analysis of Microstrip Bi-Yagi and Quad-Yagi Antenna Arrays for WLAN Applications

In this letter, the design of a microstrip bi-Yagi and microstrip quad-Yagi array antenna is presented. These designs are a derivative of the original microstrip Yagi antenna array and can achieve a high gain and a high front-to-back (F/B) ratio in comparison to the conventional microstrip Yagi structure first proposed by Huang in 1989. The proposed Bi-Yagi and quad-Yagi antenna arrays can also achieve a higher gain (3-6 dB) than the conventional microstrip Yagi array. Simple fabrication techniques can be used with these designs due to the placement of the feeding network on the same layer with the antenna elements. Furthermore, simulations and measurements demonstrate with very good agreement that the proposed arrays can achieve a gain as high as 15.6 dBi (compared to a gain of 10.7 dBi that is achieved by the microstrip Yagi antenna array) while maintaining an F/B ratio that is relatively high.