Pattern Reconfigurable Yagi Antenna Based on Active Corrugated Stripline

We present a method of designing pattern reconfigurable Yagi antenna based on the active corrugated strip line (ACSL) technology. A conventional dipole is used as a driven element, and a pair of ACSLs in different states is set on both sides of the dipole symmetrically. The ACSLs in different states have different average phase constants ( $\beta _{\mathrm {ave}}$ ), where the ACSL with a lower $\beta _{\mathrm {ave}}$ serves as a director, while the other serves as a reflector. By changing the $\beta _{\mathrm {ave}}$ of the ACSLs, a front-to-back pattern reconfigurable Yagi antenna is realized. A prototype of the proposed antenna working at the center frequency of 2.4 GHz was fabricated and measured to validate the predicted performance. The fabricated antenna has a compact size ( $0.42\lambda _{0}\times 0.42\lambda _{0}$ , $\lambda _{0}$ is the wavelength in space) and low profile ( $0.004\lambda _{0}$ ). The measured −10 dB impedance bandwidth and the gain of the antenna are 8.3% and 6.2 dBi (at 2.4 GHz), respectively.