Square Ring Antenna With Reconfigurable Patch Using Shape Memory Alloy Actuation

• Published in: IEEE transactions on antennas and propagation 2012-12, Vol.60 (12), p.5627-5634
• Main Authors: Mazlouman, S. J., Mahanfar, A., Menon, C., Vaughan, R. G.
• Format: Article
• Language: English
• Subjects: Actuation; Actuators; Antenna measurements; Antennas; Applied sciences; Exact sciences and technology; Flaps; Impedance; Materials; Patch antennas; Plates (structural members); Prototypes; Radiocommunications; Reconfigurable antenna; shape memory alloy; Shape memory alloys; smart antenna; smart materials; Springs; square ring patch; Studies; Telecommunications; Telecommunications and information theory
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2012.2213053

A pattern reconfigurable ring-patch antenna is presented. It comprises a bendable parasitic plate located in the middle of a fixed square ring. The fixed ring supports the feed, and the plate is effectively a parasitic structure. The plate's bending action is from a bisecting hinge between the rectangular halves (flaps) that can be actuated separately. The actuation is by extending a shape memory alloy spring. The restoration is by decompressing the shape memory spring action using a parallel standard spring. The parasitic plate thus reconfigures with rectangular flaps which bend up, level, and down, relative to the ring plane. As a result of the reconfiguration, the pattern of the antenna is changed while the impedance match is maintained. Simulated and experimental results are presented for the pattern and impedance of a 100 mm × 100 mm square ring patch antenna prototype operating at 1.15 GHz. The effects of some geometric parameters on the pattern and impedance are investigated in order to analyze the pattern changing mechanism. A two-element array of the reconfigurable ring-patch antenna is presented that provides further de-correlation of the patterns.