Triple-Frequency Antenna Design using Π-Shaped Triple-Frequency Impedance Matching Network

In this paper, a novel triple-frequency antenna (TFA) is presented by using a Π-shaped triple-frequency impedance matching network (Π-TFIMN), which is constructed with a transmission line and two-side triple-frequency susceptance (TFS) blocks. Each TFS block is realized with two parallel short or open stubs, providing the required susceptance at the working frequencies. To address the challenge of extracting the Π-TFIMN's circuit parameters, the genetic algorithm is used to determine the stub type, characteristic impedances, and electrical lengths. A triple-frequency monopole antenna that can concurrently work at 2.6 GHz, 3.5 GHz, and 5.2 GHz is designed and simulated. At all working frequencies, the resulting antenna has reflection coefficients lower than −20 dB and good peak gain performance.