Design and Experimental Optimization of a Canister Antenna for 18-GHz Operation

The design and experimental optimization of a canister antenna for point-to-point operation in the 17.7 to 19.7 GHz frequency band are described in this paper. The antenna, which has been briefly described earlier, 1 was designed for a digital radio system (DR 18A).2 The system will use a 274-Mb/s quaternary phase shift keying ( Q P S K ) modulation to provide eight radio channels (seven working, one protection). Each channel provides 4032 voice circuits. Anticipated typical repeater spacings will be 2.4 to 7.2 kilometers. 3 The canister is specifically designed to accommodate the antenna, transmitter and receiver units, and to be aesthetically innocuous in its environment. The initial antenna concept was first proposed by Crawford and Turrin 4 in 1969. Subsequently, the authors, drawing in part upon the603 Fig. 1--DR 18A repeater site located in Methuen, Massachusetts.