A combiner filter to allow multiple BTSs operating in a common frequency band to share a common antenna

摘要

The invention addresses the problem of allowing a first operators base transceiver station (BTS) to share an antenna with a second operators BTS when both operators are using the same frequency band, but different sub-bands of the frequency band. This is achieved by interposing a first filtering means between the antenna and the BTS of the first operator, and a second filtering means between the antenna and the BTS of the second operator. Each filtering means includes two bandpass filters (41, 43 or 45, 47) connected in parallel. Each filtering means passes two non-contiguous portions of the frequency band. For example the first filtering means could pass 33 the lowest frequency receive sub-band and a first transmit sub-band which lies above another receive sub-band blocked by the first filtering means.