US Patent 7230579 Directional dual frequency antenna arrangement

Consistent with an example embodiment, using two simple antennas with different frequencies of operation combined into an antenna arrangement a directional radiation pattern is obtained for both frequencies of operation. This is achieved by placing the antennas such that the first antenna acts as a director for the second antenna at the frequency of operation of the second antenna and the second antenna acts as a reflector for the first antenna at the frequency of operation of the first antenna. In another example embodiment, in the case of a monopole antenna the first antenna is shorter than the second antenna and can thus operate as a director while the second antenna is longer than the first antenna and can thus act as a reflector.