CPC H01P 5/18 (2013.01) [H01P 1/10 (2013.01); H03H 7/38 (2013.01)] | 14 Claims |
1. A directional coupler comprising:
a main line and a sub-line electromagnetically coupled to each other;
a variable termination circuit that is connected to a first end of the sub-line, the variable termination circuit having a variable impedance;
a variable matching circuit having a variable impedance or a variable attenuator having a variable attenuation, the variable matching circuit or the variable attenuator being connected to a second end of the sub-line; and
a control circuit configured to control the impedance of the variable termination circuit, and to control the impedance of the variable matching circuit or the attenuation of the variable attenuator,
wherein the control circuit comprises a non-volatile memory and is configured to control the impedance of the variable termination circuit in accordance with data stored in the memory, and
wherein the variable termination circuit further comprises a switch configured to vary the impedance of the variable termination circuit not based on the data stored in the memory.
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