Signal reception circuit and communication device having the same

摘要

A signal reception circuit includes a main antenna which receives signals in at least two predetermined reception frequency bands. A sub-antenna receives a signal in one of the reception frequency bands of the main antenna. A filter for interrupting a signal in the same frequency band as the reception frequency band of the sub-antenna is provided on a transmission line of a reception signal of the main antenna. A filter reflection signal in the same frequency band as the reception frequency band of the sub-antenna is induced in the sub-antenna, due to the antenna coupling thereof. The phase of the filter reflection signal is adjusted by a phase shifter between the main antenna and the filter, so that the induced signal of the sub-antenna is in phase with the reception signal of the sub-antenna. As a result, the level of the composed signal of the induced signal and the reception signal and is to be transmitted from the sub-antenna to a signal processing unit is greatly improved.