What is reconfigurable-antenna?

This repository contains the design and simulation files for a microstrip patch antenna built for vehicle-to-vehicle (V2V) communication. The antenna targets 5.9 GHz, which is the frequency band reserved for short-range vehicle safety communication (called DSRC) in many countries. The word "reconfigurable" in the name means the antenna can switch between two operating frequencies. This is achieved using a PIN diode, a small electronic component that acts like a switch. When the diode is off, the antenna operates at 5.9 GHz. When the diode is on, a slot cut into the antenna patch changes the effective shape of the radiating surface, shifting operation to a second frequency. The diode is modeled in the simulation as a simplified lumped element rather than a full physical component. The simulation was carried out in CST Studio Suite 2025, a professional electromagnetic simulation tool. The simulation reports include return loss plots (which show how much signal is reflected back rather than transmitted), radiation pattern data showing which directions the antenna radiates energy, and gain and VSWR figures that characterize antenna efficiency and match quality. The antenna is fabricated on FR-4, a common fiberglass circuit board material with defined electrical properties. The design choices are straightforward for this class of antenna: standard patch geometry on a substrate with known permittivity and thickness. The README is brief and describes this as an academic or research design exercise aimed at smart vehicle systems that need to adapt their radio frequency for safety and reliability. No build instructions or software dependencies are listed beyond the commercial simulation tool.