Dual frequency resonant base station antennas for PDC systems in Japan

Cellular mobile communication systems are being successfully developed all over the world. To accommodate the increase in the number of mobile phone subscribers, multiple systems accessing different frequency bands are being employed. In 1993, PDC (Personal Digital Cellular) systems started operation in the frequency bands of 800 MHz and 1500 MHz in Japan. The PDC systems of NTTDoCoMo in Japan also use dual frequency bands. Accordingly, the base station antennas used in the PDC system must be dual frequency resonant to reduce the cost and space required for the antenna. This paper presents a commercial dual frequency resonant base station antenna and an operation mechanism for a remote controlled beam tilting system in the vertical plane.