Optimization of an Innovative Type of Compact Frequency-Reconfigurable Antenna

This paper presents a novel patch antenna geometry that is well suited to frequency reconfigurability, achieved through the use of switches connecting metal portions to the ground plane. An optimization methodology is presented that allows operating without gaps in the 1.7–2.7 GHz band with sizes bounded by 0.17 wavelengths at the lowest frequency. The optimization procedure combines a global optimizer (genetic algorithm), and a local optimizer (1-bit neighborhood) for the geometry, and exhaustive search for the switching patterns. During optimization, performances are evaluated by method of moments simulation. The resulting structure has very attractive characteristics, such as small size, space filling, and good Return Loss (at 50 $\Omega$). A proof-of-concept prototype has been fabricated and measured, with switches simulated by soldering. Inclusion in simulation of the detailed behavior of commercial microelectromechanical systems devices is also reported.