N-Shaped Frequency Reconfigurable Antenna with Auto Switching Unit

These days the need for reconfigurable antenna is widely increased in the field of multi band wireless communication. The proposed new design of N-shaped antenna structure consists of two PIN diodes for switching purpose. They are switched automatically by a pre-programmed Arduino microcontroller unit to attain the reconfiguration of four-different bands without changing the physical dimension of the antenna. The four switching bands are 3.5 GHz (WiMAX), 2.46 GHz (WLAN), 1.2 GHz (GPS) and 2.1 GHz (UMTS). It has a center stub with two N-shaped stub carrying PIN diodes. The stubs are connected with a 50ohm microstrip feed line. The measured return loss closely follows the simulation results. Also it exhibits a good impedance matching during the four switching states. The simulation has been done through Ansoft HFSS and measured results are obtained from a Vector Network Analyzer (VNA). The obtained VSWR value lies beneath 2 for all obtained bands. The radiation pattern of the antenna is bidirectional for all the four-switching states.