This paper presents the design and realization of a compact, frequency-reconfigurable circular monopole microstrip antenna tailored for dual-band wireless communication. The antenna incorporates a circular radiating patch with integrated radial slots and a single PIN diode placed at their junction to facilitate dynamic switching between 2.3 GHz and 5.7 GHz, aligning with Wi-Fi and WLAN operating bands. The proposed structure is modeled and analyzed using HFSS, demonstrating strong impedance matching with return loss values reaching up to –20 dB and a stable VSWR below 1.7 in both reconfigurable states. Analysis of surface current distribution and radiation patterns confirms effective current steering enabled by diode switching, yielding desirable radiation behavior and directional gain. With its compact geometry, simple configuration, and reliable frequency agility, the antenna is an excellent candidate for integration into modern reconfigurable wireless devices and IoT applications.