Indoor guidance system for the blind and the visually impaired

The authors describe the design of a suitable antenna and receiver for navigation between doors in order to help the blind or the visually impaired moving inside buildings. The proposed antenna must have an extremely narrow radiation pattern. The reason behind this specification is related to the way the receiver would let the user know that a door entrance is approaching; in other words, the identification of a door is made through the search of the maximum of the radiation pattern. Once the maximum value of power is found, the person knows that he or she is correctly positioned to enter or exit the room with the help of an adequate receiver to process the signal.