A Yagi-Uda Antenna With a Stepped-Width Reflector Shorter Than the Driven Element

A Yagi-Uda antenna with a stepped-width reflector is presented. Totally different than the traditional ones, the proposed reflector is shorter than the driven element as a result of the stepped-width structure. To further understand its working mechanics, an equivalent circuit to a dipole with a parasitic element is employed to explain the shortened length of the stepped-width reflector. Then, the proposed stepped-width reflector, shorter than the driven element, was applied to design, fabrication, and measurement of a Yagi-Uda antenna. Measured results show a good agreement with the simulated ones. In particular, the total length of the reflector employed in the Yagi-Uda antenna is 50 mm, and that of the driven element is 53 mm, which verifies the shorter length of the reflector and benefits achieving a smaller size.