Modeling of U-shaped dual band patch antenna using 3D TLM method

A modeling of dual-frequency quarter-wave U-shaped patch antenna with two unequal arms on FR4 substrate, using TLM (transmission line matrix) method, is presented. The U-shaped patch antenna is fed electromagnetically by another coaxially-fed patch on the same layer, which operates at a higher frequency band. Wire conductor for patch excitation is modeled by using TLM wire node. In this paper, obtained TLM numerical results are compared with measured SWR for antenna operating at 900 and 2250 MHz bands. Good agreement between numerical and experimental results is observed, which indicates good modeling of antenna using TLM method. The antenna substrate thickness h = 5 mm corresponds to 0.015 free-space wavelength at 900 MHz. The modeled antenna is simple in structure compared with the regular stacked or coplanar parasitic patch antennas. It is highly suitable for indoor mobile communications.