| 摘要 |
PROBLEM TO BE SOLVED: To provide a high gain amplifier usable in a high frequency band. SOLUTION: Plural amplifier circuits are mutually connected, a housing containing these amplifier circuits is covered with a lid 31, and waveguides 41-43 having a cutoff frequency characteristics not to make nay mode propagate at the frequency of a usable frequency band are provided in a space 23 between the lid 31 and the amplifier circuits. In place of filling the said space with absorbers, these waveguides are formed in this space so that the extremely satisfactory radio wave insulation of output and input parts is attained for avoiding the reinjection of interference. Therefore, the limit of 45dB per housing could not be conventionally exceeded but now the maximum 90dB amplification is achieved in the same housing. |
