Design of a Monopole Antenna for WiFi-UWB Based on Characteristic Mode Theory

Abstract

In this paper, a WiFi-UWB multiband monopole antenna is designed, fabricated, and tested based on the characteristic mode theory, which mainly consists of an L-shaped metal, an "ok"-shaped metal radiator, and a T-shaped metal patch. The substrate dimensions are 40 × 43 × 1.6 mm 3 , featuring a rectangular ground plate at the substrate's bottom. The "ok"-shaped metal on the upper surface is composed of a metal ring and a curved finger-shaped metal. To improve impedance matching and broaden the bandwidth, strategic modifications are implemented. Specifically, a rectangular slot is introduced at the top of the L-shaped metal, and the T-shaped metal is rotated 90 • counterclockwise and positioned beneath the "ok"-shaped metal. The microstrip feed line, constructed from metal, incorporates a feed point. Simulation results indicate that the antenna effectively covers the frequency ranges of 2.30-2.50 GHz and 3.65-9.77 GHz. At the resonance point, the maximum return loss is below −40 dB, signifying superior directional radiation characteristics. The antenna design is characterized by a wide frequency band, simple structure, and holds significant practical value for multi-frequency communication.