Radio-over-fiber transponder with a dual-band patch antenna system

A radio-over-fiber (RoF) picocellular wireless system, comprising:

• a head-end station adapted to provide first and second downlink RF optical signals having respective first and second frequencies fA and fB, and adapted to receive and process first and second uplink RF optical signals having respective first and second frequencies fA and fB;
• an optical fiber cable optically coupled to the head-end station, the optical fiber cable having one or more optical fiber communication links adapted to carry the first and second downlink RF optical signals and the first and second uplink optical signals;
• one or more transponders respectively optically coupled to the corresponding one or more optical fiber communication links, with at least one transponder having a converter unit adapted to convert RF optical signals to RF electrical signals and vice versa;
• and
• wherein at least one transponder includes a micro-strip antenna system with first and second patch antenna elements adapted to respectively transmit and receive RF electromagnetic radiation at the first frequency fA over a first picocell, and a third patch antenna element adapted to transmit and receive RF electromagnetic radiation at the second frequency fB over a second picocell substantially co-located with the first picocell, and wherein picocells of adjacent transponders do not substantially interfere.

A method of generating first and second substantially co-located first and second picocells at respective first and second frequencies, comprising:

• providing first and second downlink RF optical signals of respective first and second frequencies fA and fBto a radio-over-fiber (RoF) transponder;
• at the transponder, converting the first and second downlink RF optical signals to corresponding first and second electrical signals;
• feeding the first electrical downlink signals to first and second patch antenna elements adapted to transmit at the first frequency fA so as to form a first picocell;
• and
• feeding the second electrical downlink signals to a third patch antenna element adapted to transmit at the second frequency fB so as to form a second picocell substantially co-located with the first picocell.