Frequency scanning antennas for aeronautical communications

A key element in frequency scanning antennas is the delay line. Low volume, lightweight delay lines for use at Ka-band frequencies can be constructed using periodically loaded waveguides which exhibit reasonably low loss. Proprietry software available at ERA has been used to synthesise these structures and this has been validated by the construction of a prototype delay line. Once slot characterisation is complete, a number of linear frequency scanning arrays may be manufactured and used to feed a cylindrical offset reflector. Using this technique, an angular sector of 3.2° by 7.2° will be covered, at a minimum level of 40 dBi, using just four beam ports and a 500 MHz bandwidth