This work investigates the frequency response of a microstrip antenna that is optically reconfigurable when exposed to laser light. The reconfiguration is executed provided by a silicon photoresistor. Without illumination the photoresistor has a resistance of 833 Ω and the antenna operates at the frequency of 395 MHz. When exposed to the intensity of 200 mW of the laser light the photoresistor shows a resistance of 0.165 Ω and the antenna can operate at 395 MHz and 630 MHz working as an optical switch.