Analysis and design of broadside-coupled striplines-fed bow-tie antennas

Abstract

The design of a bow-tie antenna fed by broadside-coupled striplines (BCS) for the 2.4-GHz ISM band is described in this letter. The two fins of the bow tie are, respectively, on the two sides of the substrate. The feeding balanced lines adopted are the BCS. A quarter-wave transformer Is used to transform the microtrip line input to the BCS feed. Analysis method based on the mixed-potential integral equation method is used to characterize the input characteristics of the bow-tie antenna. Obtained numerical results are in good agreement with experimental data. Through experiments with bow-tie antennas of various extended angles, the bow-tie antenna with a 90 degrees extended angle exhibits the widest bandwidth in the desired frequency band, which has a bandwidth of 19% for VSWR < 1.5:1.