Bypass arrangement for low-noise amplifier

摘要

The invention relates in particular to an arrangement for bypassing a low-noise amplifier (LNA), intended especially to be used in base stations of mobile networks. For the bypass, a receiver antenna filter (210) has a second output (OUT2) parallel with a first output (OUT1) connected to the LNA. The antenna filter is of the resonator type, and there is a conductive element for each of its outputs in the resonator cavity. Selection between the LNA output signal and signal coming direct from the antenna filter is made by a changeover switch (SW). The noise figure of the receiver front stage (220) will improve as the series switch on the signal path, which most degrades the noise figure, is removed between the filter and LNA, and isolation on the LNA bypass path increases.