A Novel Slot Antenna on Metal Box and Its Equivalent Circuit Derivation

Abstract

A novel compact slot antenna etched on a metal box is proposed for specified flammable environment. Its equivalent circuit is derived to illustrate its working principle. The antenna is incorporated on a hollow metal box. Two slots are carved on the box for radiation and feeding. The excitation port is set on the shorter slot. An L-shaped branch is mounted inside the box to excite the larger slot. The antenna resonates at the desired frequency by adjusting the size of the larger slot and the L-shaped branch. A prototype working at 2.4-GHz has been fabricated for validation. A formula to estimate the input impedance is proposed., and the equivalent circuit of the proposed antenna is drawn based on the formula. The results from the equivalent circuit are in good agreement with the full wave simulation.