Patent ID: 7653313

Claim:
A wireless remote access base station for converting a downstream optical signal to a downstream radio frequency (RF) signal and transmitting the converted downstream RF signal wirelessly, and converting a received upstream RF signal to an upstream optical signal and transmitting the upstream optical signal, comprising: an electro-absorption modulator (EAM) for converting the downstream optical signal to the downstream RF signal and the upstream RF signal to the upstream optical signal; an antenna for transmitting the downstream RF signal wirelessly and outputting the upstream RF signal received wirelessly to the EAM; and an amplifier, disposed between the EAM and the antenna, amplifies the downstream RF signal and outputs the amplified downstream RF signal to the antenna; a first circulator for outputting the downstream RF signal to the antenna and outputting the upstream RF signal input from the antenna to the EAM; a second circulator for outputting the downstream RF signal amplified by the amplifier to the antenna and outputting the upstream RF signal input from the antenna to the first circulator; and a filter disposed between the first circulator and the second circulator; wherein the filter comprises: a first port for inputting the downstream RF signal; a second port for outputting the downstream RF signal; first to third capacitors coupled in series between the first port and the second port; a first inductor, one electrode of which is coupled between the first capacitor and the second capacitor and the other electrode is grounded; and a second inductor, one electrode of which is coupled between the second capacitor and the third capacitor and the other electrode is grounded.