Broadband and low‐profile Yagi–Uda antenna composed of inverted‐F and inverted‐L shaped elements

A broadband Yagi–Uda antenna composed of an excited inverted-F element and two parasitic inverter-L elements, which is used for the antennas of the SSR (secondary surveillance radar) and equipped on an airplane, is proposed. By locating a director close to the excited inverted-F element, such as about 0.05λ0 for the array space between these elements, an antenna having a performance of the bandwidth of 18.8% and unidirectional pattern in this bandwidth is obtained with a total dimension of about 0.1λ0 (height) × 0.4λ0 (length). The validity of the calculated values is experimentally confirmed. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(1): 43–48, 2002