A MULTI-PATTERN ANTENNA HAVING INDEPENDENTLY CONTROLLABLE ANTENNA PATTERN CHARACTERISTICS

摘要

An antenna for providing a first antenna pattern at a first frequency o f operation and a second antenna pattern at a second frequency of operation fr om first and second RF signals, respectively. The antenna included a horn which is dimensioned to generate the first antenna pattern from the first RF signal. A conduit is located within the horn and is configured to propagate the second RF sign al in a waveguide mode. A corrugated rod having a first and a second portion is associated with the conduit. The first portion of the rod is located inside the conduit and the second portion of the rod protrudes from the conduit into the horn. The rod is configured to be responsive to the second RF signal and is operative to transition the second RF signal from a waveguide mode to a surface wave mode and propagate the second RF signal in a surface wave mode along the rod. The rod is configured to generate a second antenna from the second RF signal propagatin g in a surface wave mode. The first antenna pattern has first antenna pattern characteristics and the second antenna pattern has second antenna pattern characteristics. Changes in the dimensions of the horn will alter the patter n characteristics of the first antenna pattern but will have substantially no effect on the characteristics of the second antenna pattern. Changes in the length of the first portion of the rod will alter the pattern characteristics of the second antenna pattern but have substantially no effect on the pattern characteristics of the first antenna pattern generated by the horn.