Design of a simple antenna for mobile communications in the L-band

It is expected that second-generation mobile-communications in the L-band will be introduced to the market in the immediate future. A cellular system of mini- or micro-cells will be used to relieve the traffic congestion. Similar to the CT-2 system currently used in Hong Kong and Singapore, the new system will encompass thousands or tens of thousands of micro-cells inter-connected by the public-switch-telephone-network. Instead of the high power monopole used in the base-station of a UHF mobile-communications system, a low-power and low-cost directional antenna should be used. The capacity of the cellular system can be further enhanced by better utilization of the frequency spectrum by using various multiple-access techniques. Moreover, the communication should be more secure from eavesdropping and the spread spectrum technique may be used. To implement the aforementioned characteristics, the new antenna must be broadband. It is expected that the dumbbell-shaped wire antenna presented here will satisfy nearly all requirements previously cited. The dumbbell antenna can be used as an isolated antenna at the base-station or on top of a vehicle. Of course, it can also be treated as an element in a Yagi-Uda array installed at the base-station.<>