AM-FM-cellular mobile telephone tri-band antenna with double sleeves

An AM-FM cellular mobile telephone (MT) triband antenna with double sleeves has been designed and measured. The radiation patterns and the VSWR (voltage standing wave ratio) of the triband antenna were good at the transmitting frequency of the MT. At the receiving frequency of the MT, the radiation patterns were similar to those for a lambda /4 monopole antenna, and the VSWR was good (2.0 or less) in the 883-890 MHz range. The antenna has such a length as to make the radiation efficiency sufficient. As a sleeve can be made precisely, the antenna with sleeves is suitable for mass production. A sleeve can be used to realize a triband antenna effectively.<>