Increasing Reliability of Frequency-Reconfigurable Antennas

In this letter, the new frequency-reconfigurable patch antennas are proposed. A teaching-learning-based optimization is applied for determination of slot shape and diode(s) location(s) in the ground plane of the antennas in order to increase reliability. For this purpose, a reliability formulation obtained from the graph model is added as a constraint to the optimization problem. As examples, several different antennas with different numbers of diodes are designed including structures with single diode and a structure with three diodes. In the first category, the OFF-state switch is allocated to a frequency with higher priority. Reliability will be 100% in the more important frequency. In the second category, an antenna is proposed for switching among four bands. In order to have four bands, the minimum required number of diodes is two. In this design, in order for creation of equivalent configurations and consequently improvement of reliability, three diodes are considered. A prototype of the optimized antenna with three diodes is fabricated, and the simulation and measurement results agree suitably.