Reconfigurable frequency selective surfaces for remote sensing of chemical and biological agents

A process for detecting an analyte, the process comprising:

• providing an apparatus including a frequency selective surface (FSS), the FSS comprising a periodically replicated unit cell, the unit cell comprising a dielectric substrate and a chemoresistive material,
• the chemoresistive material having an electrical conductivity that changes on exposure to the analyte;
• determining an electromagnetic property of the apparatus, the electromagnetic property being correlated with the electrical conductivity of the chemoresistive material;
• and
• detecting the analyte using the electromagnetic property.

A frequency selective surface (FSS), the FSS comprising a periodically replicated unit cell,

• the unit cell including a chemoresistive material having an electrical conductivity that changes in a presence of an analyte,
• the FSS comprising:
• a dielectric substrate;
• an arrangement of conducting metal patches on the dielectric substrate;
• and
• at least one chemoresistive element comprising the chemoresistive material interconnecting a pair of conducting metal patches.

An apparatus comprising a periodic structure,

• the periodic structure including a pattern of metal patches and a pattern of chemoresistive material,
• the apparatus having a first electromagnetic property in a presence of an analyte, and a second electromagnetic property in an absence of the analyte,
• a difference between the first electromagnetic property and the second electromagnetic property at least in part arising from an electrical conductivity change of the chemoresistive material,
• the periodic structure being a frequency selective surface (FSS).